advanced metering technology for embedded...

ADVANCED METERING TECHNOLOGY FOR

EMBEDDED GENERATION

CONTRACT NUMBER: K/EL/000345/00/00

URN NUMBER: 06/1892

The DTI drives our ambition of ‘prosperity for all’ by working to create the best environment for business success in the UK. We help people and companies become more productive by promoting enterprise, innovation and creativity.

We champion UK business at home and abroad. We invest heavily in world-class science and technology. We protect the rights of working people and consumers. And we stand up for fair and open markets in the UK, Europe and the world.

ADVANCED METERING TECHNOLOGY FOR ADVANCED METERING TECHNOLOGY FOR ADVANCED METERING TECHNOLOGY FOR ADVANCED METERING TECHNOLOGY FOR EMBEDDED GENERATIONEMBEDDED GENERATIONEMBEDDED GENERATIONEMBEDDED GENERATION

CONTRACT NUMBERCONTRACT NUMBERCONTRACT NUMBERCONTRACT NUMBER:::: K/EL/00345/00/00K/EL/00345/00/00K/EL/00345/00/00K/EL/00345/00/00 URN NUMBERURN NUMBERURN NUMBERURN NUMBER: 06/1892: 06/1892: 06/1892: 06/1892

ContractorsContractorsContractorsContractors

E.ON UK POWER TECHNOLOGY,E.ON UK POWER TECHNOLOGY,E.ON UK POWER TECHNOLOGY,E.ON UK POWER TECHNOLOGY, STARK SOFTWARE INTERNATIONAL, STARK SOFTWARE INTERNATIONAL, STARK SOFTWARE INTERNATIONAL, STARK SOFTWARE INTERNATIONAL,

BEAMABEAMABEAMABEAMA

The work described in this report was carried out under contract as part of the DTI Technology Programme: New and Renewable Energy, which is managed by Future Energy Solutions. The views and judgements expressed in this report

are those of the contractor and do not necessarily reflect those of the DTI or Future Energy Solutions.

First published 2006 E.ON UK POWER TECHNOLOGY Copyright 2006

SUMMARYSUMMARYSUMMARYSUMMARY

The application of Micro-CHP generation for domestic properties is an area of

growing interest with the potential to help meet future demands for electricity whilst reducing carbon emissions. Unfortunately the metering and settlements arrangements for typical domestic properties cannot easily accommodate the

change in energy flows caused by the embedded generation. This has two effects:

1. The data recorded in the Settlements system is incorrect. At relatively modest levels of micro-CHP installation the impact on Settlements will be

significant and consequently changes to metering profiles are already being considered

2. The customer does not receive the benefit of exporting electricity (or

offsetting consumption) at times of peak price. It has been suggested that metering the micro-CHP installations using half hourly,

bi-directional meters rather than quarterly read, single register meters will provide a solution to both these issues.

This report explores the options for applying half hourly metering to micro-CHP installations, reviewing the technologies and processes involved. Although the

costs of metering equipment, data communication and processing represent a barrier to the widespread application of half-hourly metering with automatic meter reading to all users, for micro-CHP units more sophisticated meters,

communicating over an ADSL broadband connection, represent a realistic solution. In the short to medium term, it is suggested that the energy recorded be reconciled outside, but in parallel to, the existing Settlements system. In order for

the financial benefit to be passed on to the customer, and therefore to promote the wider take up of these new micro-generation technologies, a number of enabling actions are required from the Government and / or the Regulator.

CONTENTSCONTENTSCONTENTSCONTENTS

PagePagePagePage

1 INTRODUCTION.................................................................................................................1

1.1 The Holy Grail for Micro Generation ............................................................................ 4 2 CONCLUSIONS ..................................................................................................................5

3 ELECTRICITY METERING.................................................................................................6 3.1 Metering Roles and Responsibilities............................................................................6

3.2 Hardware Standards & Certification.............................................................................8 3.3 What to Measure ...............................................................................................................9

3.4 Communication Protocols.............................................................................................12 4 COMMUNICATIONS .......................................................................................................14

4.1 WAN Options....................................................................................................................16 4.2 LAN Options .....................................................................................................................21 4.3 Data Communicated .......................................................................................................24

4.4 Data Retriever...................................................................................................................26 5 DATA COLLECTION ........................................................................................................27

5.1 Metrology and Data Requirements for DCHP ..........................................................27 5.2 CoP5 Metering Systems ................................................................................................27

5.3 Connectivity ......................................................................................................................27 5.4 Data Collection .................................................................................................................28 5.5 Scaling up for DCHP .......................................................................................................28

5.6 Integrating Metrology and Communications...........................................................30 5.7 Two Way Communications...........................................................................................31 5.8 Multi-Utility Reading.......................................................................................................32

5.9 Control Signals.................................................................................................................32 5.10 User Interface...................................................................................................................33

6 SETTLEMENTS.................................................................................................................35 6.1 Half Hourly Settlements.................................................................................................35

6.2 HHDC Appointment Process.........................................................................................35 6.3 Non Half Hourly Settlements .......................................................................................36 6.4 Change the Rules.............................................................................................................36

6.5 Profiling..............................................................................................................................36 6.6 The Cost of Settlements ................................................................................................41 6.7 Billing..................................................................................................................................43

7 STAKEHOLDERS..............................................................................................................45

7.1 Government and Regulatory Bodies..........................................................................45 7.2 Other Stakeholders .........................................................................................................47

8 THE WAY FORWARD......................................................................................................51 8.1 Short Term Solution .......................................................................................................51

8.2 Medium Term Solution..................................................................................................52 8.3 Timescales.........................................................................................................................54

8.4 Enabling Activities...........................................................................................................54 9 GLOSSARY........................................................................................................................56

APPENDICES

Appendix A: Summary of Emerging Micro-CHP Generation Technologies Appendix B: Summary of SVA Data Interfaces Appendix C: Load Profiles and Their Use in Settlement (separate file)

of 56

1111 INTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTION

The wide scale installation of micro-generation in domestic premises is expected to form an important part of the future generation mix in Britain as the electricity

industry changes from one of centralised generation and dispatch to a more diverse arrangement of generator sizes and locations, fuel types and system management techniques1. Embedded generation within the distribution

networks, typically in the range of 1MW to 50MW is already commonplace and considerable effort is being expended to allow further deployment of embedded generators, particularly where this offers environmental benefits through

improved efficiency or the use of renewable energy supplies. This activity covers areas such as the streamlining of the connection process, but also in understanding how network control and the dispatch of generation need to be

modified in order for the distribution, transmission and Settlements systems to cope with the new sources of energy.

Micro-generation is currently in its infancy. Photo voltaic schemes have been available for some time and a simplified process to allow their connection was

established in 20002. However, as the output from these schemes is typically less than 150kWh per year export meters are rarely fitted and not all suppliers will pay for the exported power 3.

More recently micro-CHP units have been developed for domestic installation. The first of these to be made generally available is the WhisperGen4 Stirling

engine being deployed by Powergen. This has an output of 1kW and offers a more significant opportunity for electricity to be sold back to the supplier. Other

energy suppliers and equipment manufacturers are also developing new

1 Potential for Microgeneration Potential for Microgeneration Potential for Microgeneration Potential for Microgeneration ---- Study and Analysis Study and Analysis Study and Analysis Study and Analysis. The Energy Saving Trust, in conjunction with

Element Energy Limited, E-Connect and Cambridge University Faculty of Economics, was

commissioned by the DTI to study the UK potential for microgeneration technologies. Published in

November 2005, this report suggests that 30-40% of UK's electricity generation, including 6% of

small wind generation, could come from microgeneration by 2050

2 Engineering Recommendation G77:2000 – ‘Recommendations for the connection of Single-Phase

Inverter-Connected Photovoltaic (PV) Generators up to 5kVA to Public Distribution Networks’

(Electricity Association, 2000). (Now superseded by Engineering Recommendation G83 – ‘The

connection of small-scale embedded generators (up to 16 a per phase) in parallel with public low

voltage distribution networks’)

3 www.solarcentury.co.uk

“Currently the trend amongst suppliers is not to install export meters but to pay a fixed amount

per kilowatt peak installed. This means that you will be rewarded for the electricity generated from

your system even when you use it in your home – potentially doubling its value. Most of the big

utilities will buy back the energy you generate for the same price as they sell it to you although, if

you do need to switch supplier it is not a complicated process.”

4 http://www.powergen.co.uk/pub/Dom/A/ui/Residential/TechnologyAndInitiative.aspx?id=30

of 56

generation equipment for the domestic market. These include alternative micro-CHP units5 and micro-wind generators, and as the ratings of these machines and

their take up by the general public increases the importance of being reimbursed for the excess generation will be increasingly important, becoming a major factor

in the financial case behind any equipment installation, with the potential environmental benefits becoming secondary.

Just how this energy is measured is still being decided. Previous studies have

highlighted the potential difficulties which will be experienced once a significant level of micro-generation take up is reached6; at this point the errors introduced into the Settlements Process will become significant. Work is being carried out in

parallel with this study on the development of new Settlement Profiles7. These profiles, if adopted, will be distinct from the arrangement between the owner of

the CHP unit and their electricity supplier and a separate export meter may still be required.

Alternatively the imported and exported energy could be metered at the customer’s connection to the distribution system on a half-hourly basis. This would allow payment to be made for the true energy transfer and would remove

any inaccuracy in the Settlements process. The deployment of ½ hourly metering in domestic premises is not without difficulties, which include the cost and availability of suitable metering equipment, the cost of collecting the meter data

and the process of entering this data into the Settlements process.

During the development of this report, considerable progress has been made to answer the first of these challenges. Several meter manufacturers have been developing ½ hourly meters suitable for the UK market aimed at use by SME’s

with a three phase electricity supply and using GSM mobile technology as the communications channel. Outside the UK, programmes are underway in a number of countries to replace all electricity meters with new equipment with the

capability for automated meter reading (AMR). These encompass projects in Italy, Scandinavia, Australia, USA and former Eastern Block countries where large scale

investment in metering is taking place to replace obsolete equipment and to tackle fraud. These systems use a range of communications technologies including GSM/SMS, power line carrier (PLC) and low power radio. It should be noted that

not all these systems record domestic energy flows on a ½ hourly basis. 5 A summary of emerging micro-CHP technologies is included in Appendix A

6 ILEX Report “Metering, Settlement and Export Reward Options for Micro-Generation” suggests

that approximate levels of penetration for the various micro generation technologies are: Micro

CHP - 33,000 installations; Micro Wind - 25,000 installations; Micro PV – 760,000 installations; and

Micro Hydro – 9,000 installations.

7 Metering and Monitoring of Domestic Embedded Generation, DTI reference number:

JDBD/023/00417C.

of 56

Further pressure to deploy “smart” meters in the UK is now coming from other directions including the European Commission8 and from Energy Watch9. The

emphasis is on improving energy efficiency and reducing electricity consumption by providing consumers with sufficient information on their energy usage to

influence behaviour. Should these initiatives drive suppliers or meter operators to install ½ hourly meters with AMR capabilities by default, the issues relating to the metering of export energy and the processing and Settlement of this data still

remain. During the period between the initial submission to the DTI for the funding of this work and the publication of the report there has been considerable activity around

smart metering. This covers some of the original goals and includes the Ofgem consultation on smart metering10 and the report produced by Sustainability First11. Whatever the outcome of this work, and there still remains considerable doubt

over the commercial viability of ½ hourly smart metering in the domestic market, it will take some time before ½ hourly meters are ubiquitous, and even then the

majority will measure imported energy only. The aim of this project remains to identify how suppliers may obtain financial advantage from the export of energy from embedded micro-generation, which may then be returned to the owner of

the generator and hence encourage further take up of these technologies. Beyond the fundamental requirement to collect the meter data, the establishment

of two-way communication with the customer’s meter offers the potential for additional applications and services. These will become increasingly important as embedded generation becomes more widespread and active control of the

distribution network becomes a necessity. One tool available to the distribution system control engineer could be the ability to call on the generation, or back it

off, in response to changes in voltage levels and system capacity. Further applications will certainly be developed and it is therefore important that the metering interface is considered in a wider context, rather than the pure

environment of measuring energy transfers.

8 Article 13 Metering and informative billing of energy consumption of the End Use Efficiency and Energy Savings Directive. Article 13 requires 'competitively priced individual meters' for

electricity and gas, and bills based on 'actual consumption' and 'actual time of use' that are 'clear'

and frequent enough to 'enable customers to regulate their own energy consumption'. The

Directive is still in the legislative process but Article 13 has so far proceeded relatively

unchallenged. Whilst it is generally interpreted as requiring smart meters, it is unclear exactly

what needs to be implemented.

9 “Bringing Meters into the 21st Century”. Energywatch publication, August 2005.

10 Domestic Metering Innovation – Next Steps. Decision Document Ref: 107/06. http://www.ofgem.gov.uk/temp/ofgem/cache/cmsattach/15591_Metering_Innovation_Decision_doc

ument_final.pdf

11 Smart Meters: Commercial, Policy and Regulatory Drivers. Gill Owen and Judith Ward of Sustainability First, Published March 2006

of 56

This report aims to present a comprehensive review of the options and requirements for half hourly metering on micro-generation installations. This

includes:

• Information required from the meter

• Options for profiling data and the implications for the Settlements system

• Options for collecting the meter data

• Requirements for processing the data

• The interaction with the electricity supplier systems for customer management and billing

• The interaction with the Settlements System under the British Electricity Trading and Transmission Arrangements (BETTA)

• Opportunities for providing enhanced functionality such as the remote management of the micro-generation unit

• Estimates of the costs of equipment and system implementation

• Proposals on how the export energy from micro-generation units may be rewarded.

It is evident from the changes that are already taking place in the metering systems available from the equipment manufacturers and the developments in

the requirements for metering outside the UK that the way in which electricity in Britain is metered is likely to change. The conclusions to the report identify the way in which these changes to metering technology and the associated data

processing and Settlement systems will need to be developed in order to support the widespread deployment of micro-generation systems. Where enabling actions are required from the Government or Regulatory authorities these are also

presented.

For the purpose of this report, all descriptions of equipment, standards, roles and responsibilities apply in the Supplier Volume Allocation (SVA) market. The roles and responsibilities within Central Volume Allocation (CVA) are different, but are

not relevant to the metering of domestic premises. 1.11.11.11.1 The The The The Holy Grail for Micro GenerationHoly Grail for Micro GenerationHoly Grail for Micro GenerationHoly Grail for Micro Generation

To allow the Supplier to obtain the full financial benefit from the installation of micro-CHP or other domestic micro-generation, with sufficient residual value

being available after overheads such as administration and processing have been recovered, to allow some of that benefit to be passed on to the customer. If sufficient benefit is passed on then further installations will be incentivised.

of 56

2222 CONCLUSIONSCONCLUSIONSCONCLUSIONSCONCLUSIONS

This report has drawn together a considerable amount of information relating to the metering of energy flows at the domestic level, the collection and processing

of this data and the way in the data is used in the Settlements System. As the take up of micro-generation units grows, and at the same time the energy

generated by a single micro generation unit increases, the requirement for exported energy to be adequately rewarded will become overwhelming. The report proposes a method by which the exported energy may be settled outside

the existing Settlements System, rewarding customers who install micro-generation equipment, promoting the deployment of these generation technologies and allowing new metrology and communications system to be

developed. In the longer term this approach will allow for an eventual seamless transfer from existing arrangements for profiling and estimation of meter data to

a world where energy is settled on actual energy flows, in near to real time. It is suggested that the meter data from the micro-CHP units will initially be

collected over ADSL broadband connections; other communications channels are currently prohibitively expensive and the existing demographics for micro-CHP ownership match with those for broadband adoption. It is anticipated much more

than just electricity data will be gathered from these installations, covering potentially multi-utility metering and status information / condition monitoring of the micro-CHP unit. Whether the meter forms the central data collection hub for

the house, or feeds data to a separate data collector station will be determined by the equipment manufacturers.

In order for the benefits of ½ hourly metering of micro-generation to be realised, there are a number of enabling actions which are required. These cover:

• the introduction of a “Micro Generation Obligation” whereby the imbalance between profiled energy flows and actual energy flows are settled outside the Settlements system

• The consideration of ways to enable a low cost, universal medium for communicating the meter data from all properties, such as universal power

line carrier or low power radio network.

• An ongoing review of the way that the Settlements System costs are distributed.

If these proposals are implemented they will make a considerable contribution to the deployment of micro-generation technologies in the short to medium term.

of 56

3333 ELECTRICITY METERINGELECTRICITY METERINGELECTRICITY METERINGELECTRICITY METERING

There are a wide range of issues that must be taken into account when considering any changes to current electricity metering practice. This section

gives an overview of the roles and responsibilities of each party involved in domestic and SME electricity metering as well as some of the standards which apply to metering hardware. A review of what is usually metered and what could

be metered in an “advanced” application is given.

3.13.13.13.1 Metering Roles and ResponsibilitiesMetering Roles and ResponsibilitiesMetering Roles and ResponsibilitiesMetering Roles and Responsibilities

Prior to privatisation, metering was a vertically integrated operation controlled by each Regional Electricity Company. Now, however, the industry has been divided into a number of separate roles which operate in a competitive market:

Meter Asset Providers (MAP’s)Meter Asset Providers (MAP’s)Meter Asset Providers (MAP’s)Meter Asset Providers (MAP’s) – companies who own meters and supply them to Meter Operators (MAM’s) at the request of Suppliers. Previously this function

was performed by the Distribution Network Operator (DNO) and some retain the function, albeit as a separate business unit. There are, however, some new

entrants/independents who act solely as MAP’s, working as asset managers, or as a function of their MOA activities.

Meter Operator Agent (MOA)Meter Operator Agent (MOA)Meter Operator Agent (MOA)Meter Operator Agent (MOA) – (also referred to as Meter Asset Maintainer of MAM). A company that is contracted to carry out this service primarily by the Supplier (but potentially by the end customer), to install and maintain metering

equipment. Data CollectorData CollectorData CollectorData Collector – A company that is contracted by the Supplier to read the meters,

providing meter data both to the Supplier for customer billing purposes and to Settlements in respect of the Balancing and Settlements Code 12 (BSC)

requirements/obligations. Visits have to be made once every three months but there is no requirement to gain access at each visit. If the meter is not read then other reading types may be utilised (conforming with BSC requirements), e.g. a

customer’s own read (COR), or an estimate is calculated for the customer (deemed meter reading, based on historical data). There is a statutory requirement to inspect every meter at least once every two years to ensure that

the meter is safe and has not been tampered with, however this guarantees that a real read is used at least every two years.

Data RetrieverData RetrieverData RetrieverData Retriever – An Elexon registered data retriever (DR) (this principally covers in-the-field activities) reads meters on behalf of an accredited Non Half Hourly

Data Collector. The DR passes the meter register readings to the NHHDC who validates the data and forwards it the Supplier and Settlements.

12 Balancing and Settlements Code, Elexon.

http://www.elexon.co.uk/bscrelateddocs/BSC/default.aspx

of 56

For example, acting as the DR, Stark retrieves the register data from the meter. Whilst the associated interval data may have no relevance to the Settlements

process, this data can be collected and processed on behalf of any other stakeholder.

Data AggregatorData AggregatorData AggregatorData Aggregator – A purely Settlement activity, a company providing DA services is contracted by the Supplier. However, it is more usually contracted for as part of

the overall Data Processing (DP) activities, i.e. joint DC and DA. The DA receives meter reading data from the Data Collector and aggregates this data for onward transmission to Settlement via the Supplier Volume Allocation Agent.

Supplier Supplier Supplier Supplier – An energy retailer, i.e. a company that the customer pays for the supply of their electricity.

The Supplier sorts out the complicated set of contracts on behalf of each

customer, ensuring that there is a meter operator and data collector in place. This is referred to as the ‘Supplier Hub Principle’. The Supplier is responsible for assigning a Meter Point Administration Number (MPAN). Normally there is a

single MPAN for each import meter. The meters will be purchased by the MAP. In theory the Supplier may specify

which meter should be used for a customer but, in practice, this would probably incur a higher cost. As a result Suppliers tend to leave meter specification to the MAP’s.

The Supplier is also bound to the conditions set out by Elexon as a signatory to

the BSC. Elexon is responsible for the Settlements process whereby electricity flows are measured and payments reconciled between Suppliers, Generators and Transmission and Distribution Systems.

Under the BSC a series of Codes of Practice have been developed that cover all aspects of metering. The key ones for the purposes of this report are:

• Code of Practice Eight – Metering of Import Active Energy via Low Voltage Circuits for NHH Settlement Purposes

• Code of Practice Nine – Metering of Import and Export Active Energy via Low Voltage Circuits for NHH Settlements Purposes.

These documents set out the metering arrangements for customer supplies falling within their remit. Specifically they set out what should be measured, what type of meter should be used and how it should be installed and sealed. Code of

Practice 9 is very similar to Code of Practice 8 except that it introduces a means of measuring the export energy. Both Codes cover Non-Half Hourly (NHH) metering, where there is only a single register for either import or export and no interval

data is stored on the meter.

of 56

3.23.23.23.2 Hardware Standards & CertificationHardware Standards & CertificationHardware Standards & CertificationHardware Standards & Certification

3.2.1 Statutory Regulations In the United Kingdom, electricity metering is covered overall by the Electricity Act

of 1989. Within this legislation, Schedule 7 lays out the requirements for metering. The Act specifies that the meter must be of an approved type and installed in an approved manner and that the meter should be certificated by a

competent person. The responsibility for this has fallen upon the ‘Director’, in practice, OFGEM.

The Act makes clear that it is the responsibility of the Supplier to provide meters and to keep them in good order. They are at liberty to contract some other party

to carry this out. This now involves a series of contracts as OFGEM has been driving the unbundling of the meter industry in the UK.

3.2.2 Metering Approvals

OFGEM has appointed the company SGS UK Limited to carry out approvals and

certify meters in the UK. This is done on the basis that meter designs are in conformance with appropriate standards, meters are tested by the manufacturers and the meters are inspected by SGS. When a meter is certified it is given a

certification life by OFGEM. This will either be a default 10 years or some other longer period based on life prediction software. Once the meters pass through this process they may be placed on the market.

3.2.3 The Measuring Instrument Directive

The current arrangements for meter approval are subject to change as the Measuring Instruments Directive13 (MID) will be implemented in the UK, and across Europe, during October 2006. This Directive introduces harmonised

standards for the metrology aspects of domestic and small commercial meters across the European Community. In future, meters will be tested against the accuracy requirements of the MID. Testing can be carried out by any competent

European Notified Body and a type approved meter will be given an MID mark. It will be illegal to prevent an MID marked meter being put on the market anywhere

in Europe on the grounds of local metrological requirements. Due to this, as from 2006, OFGEM will simply automatically issue a certificate for any appropriately type approved meters put on the market in the UK for the markets below 100kW

maximum supply. Meters approved prior to 2006 will be able to remain on the market for 10 years

without MID marking. To some extent the immediate impact of the MID will

13 The Measuring Instruments Directive (MID) EU Directive 2004/22/EC, published to the Official Journal of the European Union.

http://europa.eu.int/eur-lex/pri/en/oj/dat/2004/l_135/l_13520040430en00010080.pdf

of 56

depend on customer demand. The new arrangements were being put in place during 2005 and were published for consultation at the end of 2005. A new set of

IEC standards are being developed by CENELEC to cover meters approved under the MID.

A related issue that is also being reviewed are the provisions for In-service Testing of Meters. Suppliers have a statutory responsibility under the 1989 Electricity Act

to maintain their meters in ‘good order’. Primarily this relates to the accuracy of the meter, which must remain within specified limits. There is an industry process in place at present to demonstrate the overall accuracy of the meters in

service. This is overseen by OFGEM and has, if the performance of sampled meters has merited it, allowed OFGEM to extend meter certificates. In line with their withdrawal from initial certification of meters, OFGEM will cease to provide

this service in 2006 and has asked industry to establish a voluntary scheme to set out how Suppliers will sample and test their meter populations to demonstrate

that they are in good order. This scheme is being developed by industry under the guidance of the Industry Metering Advisory Group (IMAG)14.

3.33.33.33.3 What to Measure What to Measure What to Measure What to Measure

Figure 1 shows the typical micro-generation layout in a normal domestic property.

Figure 1: Figure 1: Figure 1: Figure 1: Typical Electrical Arrangement for a Domestic MicroTypical Electrical Arrangement for a Domestic MicroTypical Electrical Arrangement for a Domestic MicroTypical Electrical Arrangement for a Domestic Micro----GeneratorGeneratorGeneratorGenerator

The minimum requirement is for the electricity imported and exported to be metered, either using two separate meters or a single meter with two registers.

The generator is connected between the meter output and the consumer unit within the property.

14 The Industry Metering Advisory Group (IMAG)

http://www.elexon.co.uk/Publications/NewscastExtra/ArticleDetail.aspx?ArticleId=21

Import

Meter

Ge

n

House Load

Export

Meter

Distribution System

of 56

3.3.1 Currently Measured

Under Code of Practice 8 the only requirement for the quantities to be measured is the cumulative Active energy imported in kWh. The accuracy of the meter has

to be better than ±2% across its working range. The kWh value of energy imported has to be stored in a non-volatile register.

For Code of Practice 9 the requirement is that additionally the meter installation should also record the export cumulative Active energy in kWh. This can be done

with either a single import/export meter or two import meters connected in series with the second meter connected in reverse. Elexon has required that for Code of Practice 9 metering arrangements, both the import and export registers should

have separate MPAN’s, even when both registers are on one meter. In principal, import and export contracts could be entered into with different suppliers.

Whether this option is taken up by domestic users is yet to be determined. It should be noted that the meters measure the total flow of energy in both

directions. There is no netting of the power. This is more apparent with interval metering where the meters can record both import and export values during a single ½ hour period. This is a requirement imposed by an Ofgem consultation

document entitled “The regulatory implications of domestic scale micro generation” published April 200515. This required both import and export energy to be measure separately for all sizes of embedded generators.

3.3.2 Possible to Measure

Modern electronic (static) meters are capable of far more sophisticated measurements. These will include:

4 Quadran4 Quadran4 Quadran4 Quadrant Powert Powert Powert Power – this is active and reactive energy flowing in both directions. At present there is no value related to reactive power at the domestic level but,

given that embedded generators can import or export reactive power, there may be an option of either charging or paying embedded generators on the basis of their reactive power consumption or generation.

Interval dataInterval dataInterval dataInterval data – For larger sizes of generators under Code of Practice 5, it is required that the energy flows are recorded every half hour. This data is

downloaded every day but the meters typically can store time stamped data values for longer periods, in some cases holding data for over a year. Modern meters can readily capture this data, as it is largely a question of storage capacity,

which has become much cheaper recently.

15 “The regulatory implications of domestic-scale microgeneration.” Ofgem consultation document

123/05, April 2005.

of 56

Power factorPower factorPower factorPower factor – This can be measured directly or inferred from the 4 quadrant data.

VoltageVoltageVoltageVoltage – This can be measured by the meter. Although there is no financial value to the voltage level, it can be important to the microgenerator, especially where

the generator engine is directly connected to the grid, the generator terminal voltage thus being dictated by the mains voltage. In this case the engine characteristics (for instance piston stroke) are controlled by the voltage at the

generator terminals. Another facet of voltage monitoring is the ability of the meter to record outage periods.

FrequencyFrequencyFrequencyFrequency – There is little need to measure frequency because it is common across the whole network. However, some have argued that the frequency is directly related to the load on the system16. On this basis it would be possible to

link a demand response tariff (either increasing or decreasing load or output) to the system frequency.

HarmonicsHarmonicsHarmonicsHarmonics – It is possible to measure harmonics relatively easily with a static meter. Generators that use inverters to connect to the network can be the source

of high levels of harmonics that cause problems for other users of the network. The most likely solution to this issue would be the use of standards to set maximum allowed levels of harmonics. Meters could, however, record the

maximum level of harmonics. Additional power quality measurements could be used by the DNO to assist with the investigation of supply problems and customer complaints. Currently the DNO will typically install temporary monitoring

equipment to investigate a complaint, but this data could be provided by the meter, removing the need to visit the customer premises and speeding up the

response to the problem. TransientsTransientsTransientsTransients – Rapid voltage excursions are the most troublesome system effects,

however, the short period of these spikes mean that they are difficult to measure with a relatively simple static electricity meter.

TemperatureTemperatureTemperatureTemperature – A record of the ambient temperature could be used in advanced house control systems.

Revenue ProtectionRevenue ProtectionRevenue ProtectionRevenue Protection – Modern static meters are capable of sophisticated monitoring that allows them to detect a number of frauds. The introduction of

embedded generators will make this a more important area, as the generators create the possibility of more serious fraud. For instance, if generation is being paid for, a less scrupulous customer could connect up the generation meter to the

supply. Also, the presence of the generator makes some revenue protection measures less meaningful, for instance, reverse flow is no longer an automatic indicator of fraud.

16 www.dynamicdemand.co.uk

of 56

OnOnOnOn----BoardBoardBoardBoard ProcessingProcessingProcessingProcessing – Given the capability of modern electronics it is now feasible to envisage a degree of pre-processing being carried out by the meter.

For instance, the meter could report on the site’s average profile. This would be a step between NHH and HH metering. The meter could also monitor maximum

demand and link this to the time of the demand, if this had a financial value. This is an option that could be used to reconcile the needs of embedded generators for more sophisticated tariffs and the preference for Suppliers towards simple billing

processes. CommunicationsCommunicationsCommunicationsCommunications – The issue of communications is dealt with elsewhere in the

report in much more detail. It is worth noting here, though, that many of the parameters identified above could be made available to the DNO to provide them with a form of SCADA system, supplying them with information on the operation

of the low voltage network.

GenerationGenerationGenerationGeneration – At the present moment, it is not required to meter the power output of embedded generators. For embedded renewable generators this is a requirement if customers want to be rewarded by the Renewables Obligation

Certificates (ROC) scheme. However, at present there is no tariff or reward scheme within the BSC that depends on the output of the generator.

3.43.43.43.4 Communication Protocols Communication Protocols Communication Protocols Communication Protocols

A number of protocols exist to define how the measured data should be handled,

the most important of which are summarised below: 3.4.1 Device Language Message Specification (DLMS)

DLMS has been developed within the European metering industry to provide a common protocol for interrogating meters. The basic concept is that it should be

possible to interrogate the meter without having to know any details of its internal memory structure. Given the range of possible data types for all utility metering,

this has made it become somewhat verbose. It is an internationally recognised standard, however, and meters can readily be obtained that provide DLMS communications. The standard itself allows for a range of physical connections

and new ones are being developed as they become available. A common protocol was developed in the UK that is a subset of DLMS, however it never found popularity and has been abandoned.

3.4.2 Flag

The Flag protocol was developed to provide a means to access internal data in meters. It works with the optical port on meters and governs communication with and access to the meter. The protocol does not, however describe how or where

data is stored in the meter so, to communicate with a meter, it is necessary to

of 56

know where data values are stored and how they are formatted. This means that different software is required to communicate with each type of meter.

of 56

4444 COMMUNICATIONCOMMUNICATIONCOMMUNICATIONCOMMUNICATIONSSSS

The fact that smart meters are even being considered for wide scale deployment may be attributed, certainly in part, to recent developments in communications

technologies. Communications for utility meters is a wide subject covering a plethora of

options. This is complicated by the fact that the options are interdependent, so that there are not a small number of independent options, but rather a complex matrix of potential solutions.

To make sense of these options it is useful to divide them into

• Wide area networks (WAN):- communications between the central data collection point and the house.

• Local area networks (LAN):- communications between the house communications node and the meter (or, for multi utility metering, meters).

A summary of communication systems for WAN and LAN applications is

presented in Table 1. There are a number of other concepts that are also useful to understand when

assessing this range of options.

BandwidthBandwidthBandwidthBandwidth How much data is required to be transmitted and in which direction? For meters

this would typically be relatively low in both directions. For example, a daily upload of ½ hourly profile data should not require more than 10 kByte/day of data, depending on how well it is compressed. This should be compared with the

requirements of broadband internet communications streaming multi media, where the requirement is for > 1 Mbps.

When considering bandwidth it is important to examine the bandwidth at the various points through the system. At present the bandwidth between the meter

and the main network forms the bottleneck – limited by the capability of a person (the meter reader or customer) to physically read the meter register. In time, though, as meter communications gain access to the high capacity

communications channels such as GPRS or the broadband connections into houses, it can be expected that this situation will change and that it will be the ability of the Supplier billing system and the Settlements system to accept data

that may become the bottleneck for data transfer.

of 56

Packet Packet Packet Packet VVVVersus End to End ersus End to End ersus End to End ersus End to End CCCCommunicationsommunicationsommunicationsommunications

Traditionally, meter communications are established over an End to End connection. A good example of this is the leased line arrangement where there is

a physical wire between the meter and the caller. The concept can be contrasted with SMS text messages, where the data is sent as packets of data that the communications system ensures are passed from sender to receiver without there

ever being a connection between the two. Packet communications naturally lend themselves to multiplexing, where a number of communications sessions can share the same physical medium. Packet communication networks (such as the

Internet) can also be more robust, as there are multiple paths for the packets to follow and, if one link is broken, the packets can be redirected along another. This should be compared to end to end systems where, a loss of contact during a call

will terminate the data download and require the session to be restarted. Increasingly, the backbone of the main communications systems, such as the

public switched telecommunication network (PSTN) are moving from end to end to packet protocols, although this is transparent to users.

Network TopologyNetwork TopologyNetwork TopologyNetwork Topology There are a number of ways in which components in a network can be connected

with each other that are relevant to meter communications. This analysis assumes wireless communications although the topology applies equally to wired networks.

• Peer to Peer

This is the topology used in Bluetooth networks. Each component has a direct link to the component it is communicating with. These links are all one to one. This provides for simple networks with little flexibility but each

communications node has to have the same functionality.

• Star/Concentrator

In this arrangement, the meters within a single group all connect to a single concentrator node. This may or may not be a meter, it could be just a

communications node linking the meters to the WAN system. This network arrangement offers good economy and battery life, because the individual meters only need sufficient power to contact the base station. The

disadvantages are that the size of the network is limited by the range of the individual meter. Also, the local terrain can create radio black spots where meters cannot be located.

of 56

• Mesh

A relatively new topology, mesh networks allow communications between

all meters as well as with the concentrator. The network protocol is designed to establish itself automatically. When first turned on, the meters broadcast

and respond to the other meters in their area. In this way the meters establish which meters they can communicate with and work out paths to transmit and receive data from the concentrator. The network can extend

well beyond the range of individual meters because intermediate meters can act as relay stations. The network can also cope better with black spots because local meters can provide paths around obstructions. The limits of

such mesh networks are related to the number of steps that can be tolerated before communications become too slow.

These concepts form the basis of the following description of communications options.

4.14.14.14.1 WAN OptionsWAN OptionsWAN OptionsWAN Options

The options for communicating from the central base station to a node in the

house fall into the following categories. The features and merits of the different options are shown in Table 1:

Leased LineLeased LineLeased LineLeased Line

A leased line is a dedicated telephone line used to link two locations. This is a very reliable system but is correspondingly very expensive. For data transfer a modem is required at each end of the connection. A leased line provides far more

bandwidth than would be required of a domestic meter. Leased lines are rarely used for metering applications. Even for the high value ½

hourly metering such as that under Code of Practice 1, the norm is to use a PSTN telephone connection.

PSTNPSTNPSTNPSTN

A similar arrangement to the leased line except that the public telephone system is used to connect to the meter. Again a modem is required at both ends. For domestic applications it is likely that the phone line will be shared with the

customer and it is important to prevent data calls causing their phones to ring. There are a number of techniques that can be used to achieve this. One that works with the UK telephone system is Caller Line Identification (CLI). The

principle of this is that all phone calls are preceded by a data string that identifies the caller’s phone number. The CLI modem interrogates this string and, if it

matches any in its memory, it picks up the call before the phones ring. The modem is designed to drop the line if the customer tries to make a call so that it

of 56

never blocks emergency calls. A limitation is that only lines with fixed numbers can be used, although this is not a real problem for commercial systems. The

system can go wrong if the modem fails, as it cannot pick the line up and the other telephones will ring. This is often compounded by the fact that calls are

often made during the night to avoid contention with the customer’s use of the phone.

There are a number of other systems available. These tend to depend on particular features of the local telephone network and are specific to give countries.

WirelessWirelessWirelessWireless

There are a number of different ways in which wireless communications can be established with a house.

• GSM

This is the basis of the current mobile phone system. It can be used in a very similar way to the PSTN by the use of modems to enable data

communications. Calls can be of arbitrary length but their cost increases with their length as does the risk of a communications failure during the call.

Alternatively, GSM can be used to send SMS text messages. These require much less bandwidth and are a form of packet communication so there is no

need to establish an end to end link. SMS messages also require less power to transmit and are often used with battery systems. The disadvantage of SMS communications is the limit on data length (160 characters). Long

messages can be sent in multiple SMS messages but, where the objective is to limit battery usage, this can be unacceptable.

A significant difficulty with GSM communications is that network coverage of given areas cannot be guaranteed. Although national coverage is very good,

there are always areas where reception is poor locally because of hills and other obstructions or the network does not cover it. Meter operators typically expect some 10% of sites to have meter locations that are beyond

the reach of a given network. This can be over come in many cases with the use of an external high gain antenna, reducing the level of unreachable meter sites to about 3%. This increased cost to serve could be a barrier to

the use of GSM communications for meters and alternative arrangements still need to be made for the remaining 3%. One option is to make use of the fact that the different networks (Orange, Vodafone, etc) have different

coverage. Thus by using a different SIM card it can be possible to access a site that can’t be covered by an alternative network. The challenge here is

commercial, as, traditionally, cross network charges are very high although data collectors manage this by having multiple contracts with the different

of 56

GSM service providers. Ultimately, it might be possible to get SIM cards with roaming capability, so that they simply pick up the network with the

strongest signal. This is well beyond the current commercial thoughts of the network operators.

Although GSM may appear attractive due to the widespread usage of mobile phones, the cost of the GSM modems remain high when compared with the

basic cost of a single rate NHH meter (perhaps £50 for a GSM modem, typically less than £10 for a simple single rate meters as currently installed in a domestic property). There are also questions over the long term

availability of GSM, although it would be possible to migrate to 3G if GSM were to become obsolete. This is very important for metering applications where the equipment will be installed for a minimum of 10 years.

• GPRS

General Packet Radio Service (GPRS) is a mobile data service available to users of GSM mobile phones. It is often described as "2.5G", that is, a technology between the second and third (3G) generations of mobile

telephony. It provides moderate speed data transfer. Originally there was some thought to extend GPRS to cover other standards, but instead those networks are being converted to use the GSM standard. Usually, GPRS data

is billed per kilobyte of information transceived while circuit-switched data connections are billed per second. Generally, the connection speed drops logarithmically with distance from the base station. This is not an issue in

heavily populated areas with high cell density, but may become an issue in sparsely populated/rural areas.

• 3G

3G is the next generation version of GSM. One feature is that it allows

always on internet connections so that, in theory, meters could be contacted by using TCP/IP protocols.

• Satellite

Satellite is little used in the UK for domestic data communications but it is

possible to send messages via satellite. This does not allow direct two way communications but an asymmetrical loop can be set up using PSTN or similar for the return loop. The Sky satellite network has a return loop via a

telephone modem that has been suggested for use in a smart metering network. Future developments may see the speed of the up link being increased to broadband levels.

of 56

• Hand Held Unit

Hand held units are not complete end to end solutions, as they depend on

meter readers driving close to the property containing the meter. However, they do provide a connection into the house from outside and hence come

within the WAN category. The use of hand held or drive by units is very common in the US where there is a requirement for monthly meter reads. The principle is to have a low power transceiver on the meter that constantly

monitors for calls from a handheld unit. When the meter detects transmission from the hand held unit it sends out the data as requested. This can be done by walking past or driving past. It does not provide a

return loop and communications are only available when the meter is visited.

• WiMAX

Still being developed, WiMAX is a version of the IEEE17 standards that has been seen as a fixed wireless alternative to PSTN or cable broadband

networks. It requires a combination of protocols to give long and short range communications. Central stations can reach up to 15 miles with line of sight contact. To provide economic network coverage, WiMAX is competing

to gain access to the low frequency wave bands that operate over a long range. A target for the WiMAX grouping is to acquire the frequencies being given up by analogue television.

WiMAX is considered unlikely to take off in the UK as the ADSL and Cable

networks are now extending to most areas, so undercutting WiMAX’s market. It might be more applicable in developing countries with poorer infrastructures and also for temporary networks (for instance, to provide a

temporary communications link into an event such as Glastonbury).

• Low Power Radio

Low-power radio is the concept of broadcasting at very low power and low cost, to a small community area. Low power radio products offer rapid implementation of high-reliability, cable-free data links. Transmitter power

output is fully programmable up to a maximum of 10mW, allowing the modules to be used within any of the lower-power sub-bands within the overall 868-870MHz band. A line-of-site range of 250m is easily attainable.

All encoding and decoding functions can also be handled onboard.

17 IEEE 802.16

of 56

• Power Line Carrier (PLC)

Given that the meter is connected to a copper wire network, many groups

have had the idea of using the power network for communications and a number of different standards have been developed. Put simply, a data

concentrator is placed at the low voltage (LV) transformer and this modulates the mains signal to houses connected to it. The network can send and receive data from any individual house connected to it. This has been used

in Italy, amongst other examples, to enable remote meter reading. There are a number of competing standards, which has caused some delay in the adoption of PLC. Another significant issue is that, as the frequency of the

signal is increased to increase its bandwidth, the power cables are prone to radiating radio frequency signals (as the cables are not twisted pairs, as is the case for cables specifically used for communications). This is a real

nuisance to radio enthusiasts, as it interferes with the Short Range band. This has led to a number of keenly fought battles as new standards have

been developed. Generally, the PLC community seems to be prevailing and PLC trials are continuing with a number of DNO’s.

A more significant issue for WAN PLC is the cost of developing the infrastructure. To a large extent, the cost of building the base network of low voltage transceivers at the transformers is the same regardless of how many

homes make use of it. This means that it is only economic where the majority or all of the properties in the area are going to use it. In Italy this was not a barrier as the meter reading infrastructure was installed by the

monopoly electricity supplier (ENEL) who could bring all properties into the system. In the UK, however, where there are no monopoly companies, it

would be much more of a challenge to reach agreement to adopt PLC without a direct regulatory intervention to promote the establishment of a common system across all DNO’s.

• ADSL / Broadband

Broadband connections are growing at a very high rate, with over 8 million

customers in the UK already having some form of high speed internet access, predominantly an ADSL connection through the existing telephone

line. Further initiatives, such as the one recently announced in Nottingham18, are promoting even wider access to the internet. ADSL connections are subject to the owner (normally the householder) allowing the meter

application access to their system, however for micro-CHP applications this could easily be incorporated as a requirement of the supply tariff, with the customer automatically defaulting to a less generous tariff if the connection

is unavailable.

18 http://www.connectednottingham.org.uk/AboutUs.html

of 56

• Proprietary

There are a number of proprietary systems that have been developed to

provide wide area wireless coverage in the unlicensed frequency bands. An example is offered by Elster in the US. This utilises a mesh network to offer

extended range and immunity to local shadowing of radio signals. The system suffers the same drawback as the WAN PLC networks, in that it has a fixed cost for the base system regardless of the number of meters connected

to it. This means that it is most economic when total coverage of local meters is required and does not work well if small numbers are being connected. A further disadvantage in the UK is that the higher radio

frequencies that regulations require it to use offer shorter range than in the US and, hence, higher costs.

• PAKNET

Vodaphone offer the following PAKNET package:

“Vodafone Paknet delivers remote monitoring, payment, purchasing and management information services. Many industries including retail, gaming,

transport, logistics security and utilities rely on its fast, dependable and secure communications and capacity for two-way data transfer to reduce costs, optimise processes and improve Paknet is a 24/7 managed service

with network availability exceeding 99.8%. This delivers a highly efficient and resilient service. Paknet charges are based on data usage and the number of Radio-Pad units, although your business partner may incorporate

these charges into their quotation.”

4.24.24.24.2 LAN OptionsLAN OptionsLAN OptionsLAN Options

Likewise with the WAN options, the LAN options are listed below and expanded upon in

Table 1. These can have different levels of complexity depending on the requirement. For instance a single link into a meter can be provided by an integral outstation. However, if communications are being hosted via another

data link into the house (such as the internet) or if the electricity meter is being used to provide a communications link with gas and water meters, then a more

complex LAN is required. Integral Outstation (the meter contains the node)Integral Outstation (the meter contains the node)Integral Outstation (the meter contains the node)Integral Outstation (the meter contains the node)

Where there is only a single connection required to the meter, then a simple integral modem can be used to connect the meter to the PSTN or GSM networks.

of 56

WirelessWirelessWirelessWireless

• WiFi

This is an industry standard wireless protocol19 that is increasingly used to

connect electronic equipment around the home and office. It is feasible that this link could be used to connect the meter into the home network and thence to the internet via TCP/IP protocols. It has a very high bandwidth and

is suitable for streaming multi media around the home. This makes it expensive and power hungry for the needs of normal meter communications.

• Bluetooth

Bluetooth was introduced as a wireless link to replace the many cables used to link computer equipment, such as the pc and the printer. It has shorter range than WiFi but could be used to link meters to a household LAN. As

with WiFi, it has a higher bandwidth than might be needed for meter communications with corresponding issues of cost and power consumption.

• Zibgee

Zibgee 20 is a relatively new protocol that is being adopted within the Smart Homes and commercial/industrial sectors. It has a lower data rate than WiFi

and Bluetooth but uses a mesh network to provide a wide area of coverage. It can cope with 64,000 nodes, making it ideal for use in offices, and other large buildings. The protocol is simpler that either WiFi or Bluetooth

meaning that is cheaper, requires less powerful processors and less power. It is expected to be available in meters soon.

Zibgee is well suited to multi utility metering as the power demands are low. Thus, the gas and water meters can be linked to the electricity meter that, in

turn, can provide the power hungry link to the WAN.

• Z-Wave

Z-Wave21 has been developed from a commercial communications protocol. It sits below Zibgee with slower data rates and fewer nodes. However, its proponents argue that it is better suited than Zibgee for the domestic market

where fewer nodes are required and its lower cost should give it a clear advantage. Z-Wave chips are expected to cost a few dollars each and its

19 IEEE 802.11 20 Based on IEEE 802.15.4 standard. www.zigbee.org 21 www.z-wavealliance.org

of 56

advocates believe that it will become ubiquitous in the domestic sector, allowing economic control of all aspects of the house.

Z-Wave would be even better suited to the multi utility applications as it

shares the same advantages as Zibgee along with even lower power demand. It is claimed that two AAA batteries could provide a 10 year life.

• Proprietary Systems

Where the electricity meter is part of a unified communications system provided by a single equipment supplier there is no need for open standards

to be used. In this case a proprietary communications protocol can be used, based on one of the unlicensed wireless frequency ranges. Such systems can be more reliable as the entire system can be tested by the manufacturer.

However, it leaves the owner committed to the manufacturer’s equipment and support.

• Power Line Carrier

If the electricity meter is communicating with other devices that have a

mains supply it is now relatively simple to provide a communications link between them by fitting PLC transponders in to their power supplies. The cost of the chips to enable this is little more than a few euros at each end.

Meters are already available with in-built PLC and there are a number of systems available which already use PLC communications within the house

to send data between different devices22.

22 For example, www.digitalliving.uk.ltd

21 PT/06/BC1481/R

Page 21 of 56

Table 1.Table 1.Table 1.Table 1. Summary of Communications SystemsSummary of Communications SystemsSummary of Communications SystemsSummary of Communications Systems SystemSystemSystemSystem Data SpeedData SpeedData SpeedData Speed StandStandStandStandardsardsardsards Carrier Carrier Carrier Carrier

FrequencyFrequencyFrequencyFrequency

RangeRangeRangeRange TopologyTopologyTopologyTopology Number Number Number Number

of of of of

NodesNodesNodesNodes

Battery LifeBattery LifeBattery LifeBattery Life Capital Capital Capital Capital

CostCostCostCost

Running Running Running Running

CostCostCostCost

CommentsCommentsCommentsComments

3G 2Mbs fixed

installations /

.144Mbs for

mobile

communications23

3G n.a. Star n.a Few hours Modem

costs >

£50

SIM card

rental

GSM 9.6 kbps GSM 900MHz/

1800MHz

n.a. Star n.a Few hours

Transmitting

requires 1-2 A

Modem

costs >

£50

SIM card

rental

GPRS 0.144 Mbps GPRS n.a. Star n.a Few hours Modem

costs > £50

SIM card

rental

WiMax Broad-band

speeds

IEEE 802.16 License

exempt (5GHz)

Licensed band

(3.5GHz)

800MHz

(depending on

shut down of

analog TV

channels)

Up to 50

miles (line

of sight

rural)

Star n.a not appropriate Unknown Unknown

Mega-

Net

Licensed FCC

frequency

20 miles n.a None

Elster Frequency

Hopping

Spread

Spectrum

(FHSS) ILC1 900mHz

unregulated

radio (US) -

2.4GHz in

UK

900Mhz (US)

2.4 GHz (UK)

? Mesh None Uses

embedded

WAN linked

meters to pass

on data from simple meters.

Not used in

Europe

23 http://www.mindlogic.com/3G_CELLS.shtml

22 PT/06/BC1481/R

Page 22 of 56

SystemSystemSystemSystem Data SpeedData SpeedData SpeedData Speed StandStandStandStandardsardsardsards Carrier Carrier Carrier Carrier



of of of of



CostCostCostCost


CostCostCostCost


Version of

IEEE 802.11

Itron Wireless

Itron ERT

radio

952 - 957 MHz receive

(MAS)

910 - 920 MHz transmit

Peer to Peer

CLI

(PSTN)

9600 baud V23

DTMF

n.a. End to end n.a. Modem

>£75

Ethernet 10Mbps IEEE 802.3

Leased

Line

9600 baud Too expensive.

Power

Line

Carrier

(PLC)

Cenelec En

50065-1

Lonworks

n.a. Star not appropriate

Zibgee 10 - 115 kbps IEEE

802.15.4

898 kHz

(Europe)

10-75m Mesh 65,000 Years (at low

duty cycle)

Z-Wave 9.6 kbps Proprietory 900 MHz 30m

(indoors)

100m

(outdoors)

Mesh 232 10 years on

AAA battery (so

long as not used

as

communications

node)

Bluetooth 721 kbps IEEE

802.15.1

2.4 GHz 8m (Class

II, III) 100m

(Class I)

Peer to Peer 8 4-8 hours

WiFi 11 (b) to 54 (a,g)

Mbps

IEEE 802.11

FHSS

DSSS

OFDM (IEEE

802.11a)

2.4 GHz 100m Star 100+ 1-3 hours

23 PT/06/BC1481/R

Page 23 of 56

SystemSystemSystemSystem Data SpeedData SpeedData SpeedData Speed StandStandStandStandardsardsardsards Carrier Carrier Carrier Carrier



of of of of



CostCostCostCost


CostCostCostCost


HR-

DSSS(IEEE

802.11b,g)

Ethernet 10Mbps IEEE 802.3

Power

Line

Carrier

(PLC)

not appropriate

24 PT/06/BC1481/R

Page 24 of 56

4.34.34.34.3 Data CommunicatedData CommunicatedData CommunicatedData Communicated

Smart meters with two-way communications could transmit a large amount of data to the different parties involved in the supply and distribution of electricity, and to the suppliers and maintainers of the micro generation

equipment. The following tables summarise the information that would be provided in an ideal world.

Register Register Register Register Data Data Data Data ElectricitElectricitElectricitElectricity Importy Importy Importy Import

HH HH HH HH Interval Interval Interval Interval ElectricitElectricitElectricitElectricity Importy Importy Importy Import

Register Register Register Register Data Data Data Data EEEElectricitlectricitlectricitlectricity y y y ExportExportExportExport

HH HH HH HH Interval Interval Interval Interval ElectricitElectricitElectricitElectricity y y y ExportExportExportExport

HH HH HH HH Interval Interval Interval Interval GasGasGasGas GeneratioGeneratioGeneratioGenerationnnn

HH HH HH HH Interval Interval Interval Interval Electricity Electricity Electricity Electricity GeneratioGeneratioGeneratioGenerationnnn

Supplier Supplier Supplier Supplier � � � � � �

ConsumerConsumerConsumerConsumer � � � �

DCHP DCHP DCHP DCHP MaintenancMaintenancMaintenancMaintenanc

eeee

� �

SettlementsSettlementsSettlementsSettlements � �

NHHDC/DANHHDC/DANHHDC/DANHHDC/DA � �

Data Data Data Data RetrieverRetrieverRetrieverRetriever

� �

Table 2.Table 2.Table 2.Table 2. InfoInfoInfoInformation Required by the Key Stakeholdersrmation Required by the Key Stakeholdersrmation Required by the Key Stakeholdersrmation Required by the Key Stakeholders

RegisterRegisterRegisterRegister Data: Data: Data: Data: Electricity Electricity Electricity Electricity

ImportImportImportImport

HH HH HH HH Interval:Interval:Interval:Interval: Electricity Electricity Electricity Electricity


Register Register Register Register Data: Data: Data: Data: Electricity Electricity Electricity Electricity

ExportExportExportExport

HH HH HH HH Interval:Interval:Interval:Interval: Electricity Electricity Electricity Electricity


HH HH HH HH Interval: Interval: Interval: Interval: GasGasGasGas

GenerationGenerationGenerationGeneration

HH HH HH HH Interval: Interval: Interval: Interval: Electricity Electricity Electricity Electricity


SupplierSupplierSupplierSupplier Bill consumer for energy purchased. Introduce multi-part

TOU tariff with up to 8 tariff registers

Pay consumer for energy exported

Profile data to determine time (and real value) of

energy exported

EEC 3??

Table 3.Table 3.Table 3.Table 3. Information required by the SupplierInformation required by the SupplierInformation required by the SupplierInformation required by the Supplier

25 PT/06/BC1481/R

Page 25 of 56

RegiRegiRegiRegisterstersterster Data: Data: Data: Data:

ElectriciElectriciElectriciElectricity ty ty ty ImportImportImportImport

HH HH HH HH Interval:Interval:Interval:Interval:

Electricity Electricity Electricity Electricity ImportImportImportImport

Register Register Register Register Data: Data: Data: Data:

ElectriciElectriciElectriciElectricity ty ty ty ExportExportExportExport


Electricity Electricity Electricity Electricity ExportExportExportExport

HH HH HH HH Interval: Interval: Interval: Interval:

GasGasGasGas GeneratioGeneratioGeneratioGenerationnnn


Electricity Electricity Electricity Electricity GeneratioGeneratioGeneratioGenerationnnn

ConsumConsumConsumConsumerererer

Demand side management

Demand side management.

Performance monitoring of DCHP

Performance monitoring of DCHP

Table 4.Table 4.Table 4.Table 4. Information required by the ConsumerInformation required by the ConsumerInformation required by the ConsumerInformation required by the Consumer

RegisterRegisterRegisterRegister Data: Data: Data: Data:

Electricity Electricity Electricity Electricity


HH Interval:HH Interval:HH Interval:HH Interval: Electricity Electricity Electricity Electricity


Register Register Register Register Data: Data: Data: Data:







GasGasGasGas





DCHP DCHP DCHP DCHP MaintenanceMaintenanceMaintenanceMaintenance

Remote performance monitoring of DCHP

Remote performance monitoring of DCHP

The DCHP Maintenance provided would also benefit from status information such as running hours, machine temperatures and any alarms that may be registered.

Table 5.Table 5.Table 5.Table 5. Information required by DCHP Maintenance ProvidedInformation required by DCHP Maintenance ProvidedInformation required by DCHP Maintenance ProvidedInformation required by DCHP Maintenance Provided

RegisterRegisterRegisterRegister Data: Data: Data: Data:






Register Data: Register Data: Register Data: Register Data: Electricity Electricity Electricity Electricity





HH HH HH HH IntervIntervIntervInterval: al: al: al:

GasGasGasGas





SettlementsSettlementsSettlementsSettlements B&SC

requirement

B&SC

requirement

Table 6.Table 6.Table 6.Table 6. Information required for Settlements PurposesInformation required for Settlements PurposesInformation required for Settlements PurposesInformation required for Settlements Purposes

RegisterRegisterRegisterRegister

Data: Data: Data: Data: Electricity Electricity Electricity Electricity


HH HH HH HH

Interval:Interval:Interval:Interval: Electricity Electricity Electricity Electricity


Register Register Register Register

Data: Data: Data: Data: Electricity Electricity Electricity Electricity

ExExExExportportportport

HH HH HH HH

Interval:Interval:Interval:Interval: Electricity Electricity Electricity Electricity


HH HH HH HH

Interval: Interval: Interval: Interval: GasGasGasGas


HH HH HH HH

Interval: Interval: Interval: Interval: Electricity Electricity Electricity Electricity


NHDDCNHDDCNHDDCNHDDC Supplier Supplier

Table 7.Table 7.Table 7.Table 7. Information required by NonInformation required by NonInformation required by NonInformation required by Non----Half Hourly Data Processor / Half Hourly Data Processor / Half Hourly Data Processor / Half Hourly Data Processor /

AggregatorAggregatorAggregatorAggregator

26 PT/06/BC1481/R

Page 26 of 56

4.44.44.44.4 Data Retriever Data Retriever Data Retriever Data Retriever

An Elexon registered data retriever (DR) reads meters on behalf of an accredited Non Half Hourly Data Collector. The DR passes the register reads to the NHHDC who validates the data and forwards it the supplier.

RegisterRegisterRegisterRegister

Data: Data: Data: Data:


HH HH HH HH

Interval:Interval:Interval:Interval:


RegisRegisRegisRegister ter ter ter

Data: Data: Data: Data:


HH HH HH HH

Interval:Interval:Interval:Interval:


HH HH HH HH

Interval: Interval: Interval: Interval:

GasGasGasGas GenerationGenerationGenerationGeneration

HH HH HH HH

Interval: Interval: Interval: Interval:

Electricity Electricity Electricity Electricity GenerationGenerationGenerationGeneration

Data RetrieverData RetrieverData RetrieverData Retriever B&SC

requirement

� B&SC

requirement

� � �

Table 8.Table 8.Table 8.Table 8. Information required by Data RetrieverInformation required by Data RetrieverInformation required by Data RetrieverInformation required by Data Retriever

27 PT/06/BC1481/R

Page 27 of 56

5555 DATA COLLECTIONDATA COLLECTIONDATA COLLECTIONDATA COLLECTION

5.15.15.15.1 MetrolMetrolMetrolMetrology and Data Rogy and Data Rogy and Data Rogy and Data Requirements for DCHPequirements for DCHPequirements for DCHPequirements for DCHP

Assuming the supplier continues to trade in NHH market, the information

needs of all the stakeholders identified above can be met with a metering device that provides:

• Cumulative registers for both Import and Export kWh

• 30 minute interval data for both Import and Export kWh

• Up to 8 electricity TOU tariff registers, multiple seasons etc.

• At least two additional logging inputs; one to record gas consumed in generation and the other to measure kWh generated.

• To facilitate multi-utility billing, a third input may be desirable to log the gas consumption recorded at the revenue meter.

This is not a demanding specification for metering product. Some products

are already available that can deliver on this specification. 5.25.25.25.2 CoP5CoP5CoP5CoP5 M M M Metetetetering Sering Sering Sering Systemsystemsystemsystems

CoP5 metering is mandatory for all supplies where demand exceeds 100kW and for all supplies trading in the HH market. It is considered here to gain an

understanding of the data transfer and processing required should HH metering be applied more widely, for instance as a result of the wide scale take up of micro-CHP units. The hardware configuration typically comprises a

metrology device, the CoP5 meter, together with a separate communications device; a PAKNET PAD or a PSTN/GSM modem. The modem or PAD connects to the meter via an RS232 serial port. The use of separate metrology and

communications devices impacts heavily on the cost of the metering system and this has been a significant barrier in expanding the use of AMR into the NHH market.

5.35.35.35.3 ConnectivityConnectivityConnectivityConnectivity

The UK HH market is built around an outbound AMR architecture that uses a mixture of carriers; PSTN, PAKNET (X25 wireless) and GSM. This architecture relies on complex meter communications protocols (IEC61107, DLMS) initiated

by the central data collection system. Subject to the meter and carrier type, it can take up to two minutes to complete the collection cycle with a remote

electricity meter. In an outbound AMR system, there is a linear relationship between the number

of meters and the number of dedicated communications devices (modems) required to collect the data within the prescribed time period. This relationship makes it expensive to scale up and operate large outbound AMR systems.

28 PT/06/BC1481/R

Page 28 of 56

Communications costs are also a contributory factor in making outbound AMR expensive. PSTN rental charges are high relative to the call charges, similarly

for PAKNET. GSM is now the favoured carrier because SIM charges are low relative to PSTN line rental and connection charges. Unfortunately, Circuit

Switched Data (CSD) calls over GSM are high relative to both PSTN and GSM. 5.45.45.45.4 Data CollectionData CollectionData CollectionData Collection

As outlined above, outbound AMR using PSTN or GSM requires dedicated circuits, and employ complex communications protocols to interrogate the remote meter. It can take up to two minutes to complete a typical CoP5

communications session. In addition to synchronizing the meter’s clock, by the end of the session the net result in terms of data collected is as follows:

• 48 HH kWh readings

• 48 HH kVArh lag readings

• kWh cumulative register read

• Meter self-test status flags.

An outbound AMR architecture requires a complex mix of technologies to collect and store a relatively small data payload.

Notwithstanding the cost impact of needing to manage two MPANS per site, Import and Export, Settlements requirements dictate the operational performance of the data collector. Suppliers require HHDCs to submit 99%

actual data into Settlements by ‘SF’, the date of the first Settlements run. Because estimation has such a negative impact on the quality of billing, most suppliers require HHDCs to achieve this level of performance well before SF.

With high fixed operating costs, the cost to serve in the HH market quickly becomes inelastic.

5.55.55.55.5 Scaling up for DCHPScaling up for DCHPScaling up for DCHPScaling up for DCHP

Faced with the potential for 100,000’s of DCHP installations, an outbound AMR

based on a CoP5 type metering systems, is unlikely to deliver a cost effective solution. A radical change of direction is required. Fortunately, technology

has moved on, and there are a number of alternatives to evaluate.

5.5.1 Inbound AMR Inbound AMR reverses the flow of control between devices; no longer is it the

central software system that initiates the collection process. Instead the metering system kicks off the process. Of the many communication options

detailed in sections 4.1 and 4.2 the following are most suitable for advanced metering of embedded generation.

29 PT/06/BC1481/R

Page 29 of 56

5.5.1.1 Inbound Connectivity Options

PSTNPSTNPSTNPSTN – Modems have been designed but not commercially developed that can initiate the dial-up connection to the central software system. Data transmission costs are marginal – the cost of calls. However, as per outbound

PSTN, it is not scaleable. GSMGSMGSMGSM – Circuit switched data (CSD) calls – as per PSTN

SMSSMSSMSSMS – SMS is a highly scaleable technology but is restricted to 160 bytes per message. The potential data requirements (see above ‘Metrology and data

requirements for DCHP’) could require four or five SMS messages if information beyond the basic 48 half hourly readings are required making this

technology uneconomic for a DCHP installation. Two tier systemsTwo tier systemsTwo tier systemsTwo tier systems – Two tier systems can scale up to large volumes but require

the deployment of a dedicated infrastructure. The infrastructure requires a high population density of devices for it to be economical. DCHP will be a ‘distress’ purchase in the most part, that is, it is unplanned. This is

incompatible with the commercial needs of two-tier systems Power Line Carrier (PLC)Power Line Carrier (PLC)Power Line Carrier (PLC)Power Line Carrier (PLC) – The most commonly cited example is the ENEL

initiative that specified an Echelon PLC module in the meter that communicates with locally installed data concentrators. The data

concentrators link to a central collection system via broadband connections. At this time this system only delivers monthly register reads for billing. It does not deliver interval data.

In Scandinavia, PLC has been used to feed data to concentrators which then used GPRS to communicate the data to a central collection system.

WPAN (ZigBee)WPAN (ZigBee)WPAN (ZigBee)WPAN (ZigBee) – The infrastructure requires a high population density of

devices for it to be economical. GPRSGPRSGPRSGPRS – GPRS sets up a wireless TCP/IP session over the existing GSM

network. It needs fixed IP address and so requires a Virtual Private Network (VPN) set-up with the service provider. It can be set-up to operate in outbound or inbound mode. Inbound services are much more economical as GPRS can

deliver ‘long’ text messages. Broadband & WLAN (WiBroadband & WLAN (WiBroadband & WLAN (WiBroadband & WLAN (Wi----Fi)Fi)Fi)Fi)

• Market penetration of broadband

There are approximately 25.0 million households in the UK. Of these, 17 million have PCs and 15 million have internet access. Over 8 million

30 PT/06/BC1481/R

Page 30 of 56

households have broadband access to the internet. Broadband provision is either via cable or DSL of which cable has 35% market share and DSL

65%. An industry forecast suggests that broadband will have reached over 16 million households by 2010.

• Market penetration of Wi-Fi

In the USA 1 in 5 broadband users have a home network with WiFi

becoming the predominant technology24. In the latter part of 2005 and early 2006, the leading ISPs and PC retailers such as Dixon’s PC World were aggressively marketing WiFi.

The same USA report indicates that the adoption of Wi-Fi is in higher income households with more than one PC.

5.65.65.65.6 Integrating Metrology and CommunicationsIntegrating Metrology and CommunicationsIntegrating Metrology and CommunicationsIntegrating Metrology and Communications

We are now seeing European hardware manufacturers grasp the nettle of integration combined with a choice of connectivity solutions. Iskraemco are the first European manufacturer to integrate a GSM/GPRS communications

device into a meter, the MT423 and offer this to the market. When combined with SMS messaging, integration delivers significant cost benefits and makes

AMR viable in the UK’s NHH electricity market. A number of other manufacturers, such as PRI Limited now offer similar products.

Having demonstrated that GSM/GPRS/SMS technologies may be integrated into the basic meter design, it is reasonable to expect other communications systems to be similarly integrated. This means that PLC, Bluetooth or WiFi

enabled meters are entirely feasible and meters are already being developed with low power radio interfaces.

Should ½ hourly metering become the standard for all domestic properties then it may be that a combination of technologies are required. However for

the particular application being considered here, i.e. Domestic CHP, then WiFi presents the most attractive option.

Currently the majority of DCHP purchases are being made by more affluent households who may already have a PC and broadband connection. The incremental cost of providing a wireless router, or even providing the ADSL

connection as part of the DCHP package will be small when compared with the overall cost of the installation. In the medium to long term it is considered that DCHP will play a part in the fight against fuel poverty and we will start to see a

significant number of installations in households that do not fit the criteria described above. In this case the argument for wide scale wireless internet

24http://www.forrester.com/Research/Document/Excerpt/0,7211,35004,00.html

31 PT/06/BC1481/R

Page 31 of 56

developments such as those considered for Nottingham18 and Milton Keynes will be strengthened.

There are concerns amongst supply companies that the consumer may do

something that affects the flow of data from the DCHP and metering equipment. This is a valid concern, but again for the DCHP market this risk could be managed through a condition of supply which requires the

homeowner to maintain the availability of the communications link. Should the link fail then the meter supply would revert to the standard import only, quarterly read meter and the homeowner would lose all the benefits

associated with the installation of a more sophisticated meter.

5.75.75.75.7 Two Way CommunicationsTwo Way CommunicationsTwo Way CommunicationsTwo Way Communications

Two-way communications in advanced meters would allow the meters not only to send out their readings but also to receive instruction and hence be remotely programmable. These instructions may adjust the read schedules,

demand an instantaneous read or instruct a more advanced function such as remote disconnect.

This added functionality is likely to add significant value and feature in a minimum specification. The bandwidth required for these instructions is not

likely to exceed that for the out bound meter read communications, as the meter would have a predefined set of instructions which it can accept and will therefore only require the identification string and essential information. For

example an instruction to change the read schedule from 48 half hourly reads to 24 hourly reads may only require the identifier, a short string of characters and the new number of reads – 24.

There are some important security considerations which need to be taken into

account when receiving messages at a meter. If the communications solution is not end-to-end, i.e. there is not a direct one to one connection, then the meter must ensure that it is receiving information from an authorised source

and that it is of a readable form. It is likely that the numbers or IP addresses from which the meter can receive messages will need to be hard wired into the meter and messages will need to begin with a string that announces the

format of the message. If SMS messaging was to be used the system would be susceptible to “spam” messages which are often sent to randomly generated numbers. While advanced communications are expected to help

combat fraud through functions such as tamper alarms they also open up a new range of security weakness points which must be fully researched and the

identified risks mitigated. Meters with two way communications which have recently been placed on the

market include features to provide this additional security. For example, Iskraemeco are marketing an advanced meter which is programmable with

32 PT/06/BC1481/R

Page 32 of 56

two trusted SMS senders, these numbers could only be infiltrated if it were possible to clone the relevant SIM card or hack into the network. Again,

similar products have now been marketed by other manufactures such as PRI Ltd.

5.85.85.85.8 MultiMultiMultiMulti----Utility ReadingUtility ReadingUtility ReadingUtility Reading

There is a strong demand for multi-utility metering from Suppliers if they are

to invest in remote metering. As most suppliers offer both electricity and gas to their customers they will require a common solution for both products. In the future it may be possible to offer a complete utility package from one

company, including energy, water, and telecoms. There are a variety of communications channels available for all types of meter (electric/gas/water). A key aspect of gas and water metering is that there is no local power source

to support the communications channel. This is not the case for electricity meters, which can draw power from the mains. The option of providing a mains voltage supply to the gas and water meters is uneconomic so the only

practical option is to provide them with battery power. This imposes significant limits on the maximum power draw and long term operation of the

meters. These limitations can be accepted and some products are available that

provide GSM communications for gas or water meters. However, to achieve the required battery life the meters make a limited number of calls and use only the SMS text channel. The size of the battery supply results in the units

being expensive and limits their data transfer capability. They also require a visit at least once every 10 years to replace the battery.

As the power draw on the communications and battery is directly related to the range of the signal, it makes more sense to use the electricity meter as a

data concentrator and then the wireless communications from the water and gas meters will have much shorter range and lower power demands. A number of products are available that offer this functionality.

From a DCHP point of view it may be advantageous to offer a metering package that provides correlated data on gas consumption and electricity

generation/usage. Likewise, any solution for micro-renewables such as micro-wind and micro-solar could use the meter as a data concentrator for data such as wind speed or sunlight. This concept heads towards the provision of

Energy Services rather than simply fuel supply. This is being promoted by the government in the Energy Review and is seen as a way of enabling Suppliers

to market energy efficiency.

5.95.95.95.9 Control SignalsControl SignalsControl SignalsControl Signals

The capability of modern electronics and communications make it possible to include a large range of control signals in modern meters. Signals sent to the

33 PT/06/BC1481/R

Page 33 of 56

meter via any of the communications methods discussed, may remotely disconnect/reconnect supply in the case of change of tenancy or supplier. A

control signal may also limit the amount of energy consumed by a customer or encourage a reduction in consumption at times of high demand– a process

commonly referred to as Demand Side Management (DSM). These load control signals could activate a switch that cycles loads with inherent heat stores such as water heaters or air conditioners. These control facilities are

not restricted to sites with embedded generation but would enable the transmission and distribution systems to be operated more effectively to support embedded generation technology.

Two way communication also opens up the possibility of downloading new tariffs to prepayment meters, or to meters which display the consumption in £

and pence, or avoided carbon emissions as well as, or instead of, kWh.

An extension of the control signals concept, which would directly influence and add value to embedded generators, is the ability to remotely bring them on line – aggregating significant numbers of small generators could provide

important peak demand-matching capability. The level of reactive power consumed or exported could also be remotely controlled, providing further stability to the grid. If control features were to be included in any deployment

of advanced metering, half hourly metering would become essential to ensure that generation is fairly rewarded and to ensure that the requested generation / load modulation is actually delivered.

5.105.105.105.10 User InterfaceUser InterfaceUser InterfaceUser Interface

A user interface is not an essential requirement of an advanced meter but it may play an important role in modifying consumers’ behaviours, encouraging them to operate in a more efficient manner. This generally comes under the

heading of Smart Metering. Several trials of Smart Metering are currently underway which include work by Powergen to present information in the

customers’ bills in a way that drives down consumption to the planned deployment by EDF and National Energy Action of 3000 meters which include a remote display in the house 25.

A user interface could take many forms26 ranging from a standard cumulative register to a display unit in the house showing a wide range of data. Some of

the many features that may be included on a user interface are listed below:

• Real time usage and generation data

• Current energy usage in pence per minute

25 http://www.nea.org.uk/News_releases/?article_id=267 Cutting Energy Bills: Trial of Innovative

“Smart Meters” Starts 26 Design Council RED – Future Concepts

http://www.designcouncil.org.uk/futurecurrents/HM_home_monitoring.php and

http://www.designcouncil.org.uk/futurecurrents/HM_outline_tracker.php

34 PT/06/BC1481/R

Page 34 of 56

• Level of electricity being imported/exported per day or over any given period

• Daily usage/generation profile

• Net import/export profile

• Carbon emissions saved/emitted

• Control action currently in effect

• Control action due to take place

• Price signals, tariff rate currently high/medium/low

• Carbon credits received to date/for billing period

• Level of carbon quota used The above list is by no means exhaustive and many of the features mentioned

would equally apply to sites without micro-generation installed. It is not yet understood whether consumers’ behaviour can be modified by

providing them with information on their energy usage. Trials by npower and Powergen are addressing this by offering the Electrisave load monitor 27 to their

customers. The Electrisave device is a wireless monitor which displays how much electricity a customer is using at any given time and the resultant carbon dioxide emissions. A current sensor on the meter cable transmits the

information to the portable display unit, however if successful these features may be integrated into the meter itself. A modification in behaviour may result in the supplier being eligible for carbon credits or EEC (Energy Efficiency

Commitment) payments. Applying this concept to the advanced metering of embedded generation

could provide the user with an array of valuable information such as their import and export readings, and allow them to balance their usage against

their generation capacity. It is not difficult to imagine that users would quickly learn to stagger the use of their larger appliances in order to avoid importing electricity.

User interfaces may also be used as a gateway to the home, allowing customers to top up their pre-pay meters. This is an attractive proposition for

the retail companies, for which dated systems mean revenue is regularly lost where prepayment accounts are concerned. Value may also be added by using the display units to relay information of interest such as the local

weather forecast or as a marketing tool to display current offers and promotions. However, a prominent display in the home is not the only way to

reach the end user. With meters capable of gathering, storing and transmitting large amounts of data a wide range of display media are available; such as personal web pages, customised bills, digital TV interfaces and SMS text

messages.

27 http://www.npowermediacentre.co.uk/content/detail.asp?ReleaseID=404&NewsAreaID=2

npower Uses New Device To Save Energy And Inform Smart Metering Strategy

35 PT/06/BC1481/R

Page 35 of 56

6666 SETTLEMENTSSETTLEMENTSSETTLEMENTSSETTLEMENTS

6.16.16.16.1 Half Hourly SettlementsHalf Hourly SettlementsHalf Hourly SettlementsHalf Hourly Settlements

To register a new half hourly meter into Settlements is a complex process.

The SVA Data Catalogue details the data interfaces required by Supplier Volume Allocation under the BSC. The steps required to register a new MPAN are given below and the full list of data flows referred to is given in Appendix

B. It is important to note that Import and Export energy flows are assigned unique MPANs (Metering Point Administration Number) and each MPAN is separately registered.

6.26.26.26.2 HHDC Appointment ProcessHHDC Appointment ProcessHHDC Appointment ProcessHHDC Appointment Process

• Consumer contracts with a Supplier and a Meter Operator Agent (MOA)

• Supplier sends a D0155 to HHDC and another to the MOA

• Supplier sends a D0142 to the MOA instructing the MOA to install or change a meter

• HHDC and MOA respond to Supplier within 1 day with a D0011

• Supplier sends a D0148 to HHDC and MOA (indicating who the HHDC/HHDA/MOA is to each of the other parties)

• MOA sends HHDC a D0268 (Meter Technical Details).

HHDA AppointmentHHDA AppointmentHHDA AppointmentHHDA Appointment

This appointment process is similar to HHDC. The definitive instructions to Aggregate come from the 'MPAS' system within each Distribution area. These come in the form of a D0209 and are sent as a result of a D0205 sent to MPAS

by the Supplier.

At the end of the process an HHDC should hold:

• D0155 from Supplier



• D0209 from MPAS. In addition to the above the HHDC receives:

• D0289 - Notification of Estimated Annual Consumption for estimation purposes

• D0131 - Metering Point Address details

• D0302 - Notification of Customer Details.

36 PT/06/BC1481/R

Page 36 of 56

A HHDC sends the following flows indicating readiness to dial and with what frequency.

• D0012

• D0051.

Daily operations Daily operations Daily operations Daily operations

• D0275 and/or D0036 (HH Data) sent daily to Supplier, Aggregator and Distributor by HHDC

• D0001 - Faults are reported to MOA by HHDC and copied to Supplier

• D0002 - Replies to D0001s are received by HHDC

• D0005 - From MOA to HHDC to request a 'Proving Test' - where some technical data has changed

• D0003 - (HH Data sample) sent to MOA by HHDC in response to above

• D0214 - From MOP to confirm a 'Proving Test' is OK

• D0139 - Energisations/DeEnergisations are sent by the MOP to HHDC

• D0040/D0298 - Sent daily by HHDA to Supplier and to SVAA (organisation that determines what is owed by the Suppliers to the Generators).

6.36.36.36.3 Non Half Hourly SettlementsNon Half Hourly SettlementsNon Half Hourly SettlementsNon Half Hourly Settlements

The overall process is not that dissimilar to the half hourly market. However, the following differences are worth recording.

• The Meter Technical Details are contained in two flows, the D0149 and the D0150.

• Operationally, there is no daily requirement to process interval data, only a monthly requirement to collect and validate the meter register read(s) and issue them to the Supplier using a D0010 flow.

6.46.46.46.4 Change the RulesChange the RulesChange the RulesChange the Rules

The HH and NHH markets are discrete; one operates on daily interval date (HH), whilst the other on monthly register reads. There is no middle ground. Any significant changes will have a major impact on all market participants

who will need to revise their software systems. The timescales and likely costs suggest that any major modifications will have to be mandated by OFGEM.

6.56.56.56.5 ProfilingProfilingProfilingProfiling

In the NHH market, the allocation of energy between suppliers is achieved

through a sophisticated method of profiling. A detailed explanation of how the

37 PT/06/BC1481/R

Page 37 of 56

profiling process works in included in the appendices of this report28. The key features are:

• All energy entering the distribution system at the Grid Supply Point (GSP) is accurately metered and recorded for each ½ hour interval throughout

the day.

• Any HH metered loads are subtracted from this metered volume. Similarly, any embedded generation which operates in the ½ hourly

market is added to the metered volume. The value obtained represents all the energy consumed by sites with NHH meters.

• Each NHH meter is allocated to a particular Standard Settlement Class (SSC), effectively defining which profile to use – There are 8 profile classes covering domestic customers, economy 7 customers and non-

domestic customers.

• For each day, the meter advance for each customer is calculated – based either on actual meter readings or an estimate of what the meter reading

would be if were available.

• The standard profile consists of 48 half hourly values representing the

typical daily load shape for that class of customer.

• This profile is modified to take account of factors such as noon effective temperature, sunset and the day of the week. These factors are referred

to as regression coefficients.

• By multiplying the modified load profile by the calculated meter advance

it is possible to derive a half hourly energy flow for each half hour of the day.

• For each supplier, the total energy supplied to the company’s customers can then be calculated.

• Finally, any mismatch between the total calculated energy supplied to all the customers under the GSP and the actual energy metered at the GSP is

allocated across all the suppliers. This correction, the GSP Group Correction Factor is also used to monitor the accuracy of the overall

profiling process.

28 The information on profiling has been provided by John Lucas and Jon Spence of Elexon.

We are very grateful for their assistance in understanding how the profiling system operates.

38 PT/06/BC1481/R

Page 38 of 56

Although this process appears to be very complicated it has been in operation for many years, and there are no general calls for it to be overhauled or

replaced.

There are a number of key points that need to be emphasised when considering how the profiling system works:

There is a disconnect between the payments a Supplier makes for the energy There is a disconnect between the payments a Supplier makes for the energy There is a disconnect between the payments a Supplier makes for the energy There is a disconnect between the payments a Supplier makes for the energy they purchase, and the bills that thethey purchase, and the bills that thethey purchase, and the bills that thethey purchase, and the bills that the Supplier issues to their customer. Supplier issues to their customer. Supplier issues to their customer. Supplier issues to their customer.

Although the Supplier is in business to make a profit, during any half hour period the cost of the energy contracts is not translated into a variable half-hourly energy charge to the NHH metered customer. This means that the

Supplier is free to offer whatever tariff or incentives they feel is appropriate. The purpose of the BSC is to ensure that the Supplier is accurately charged for

the customers’ electricity and use of system. It is entirely up to the Suppliers how these costs are recovered from the customer.

There is no reason therefore, why DCHP units should be metered in the HH market – provided the Supplier and the owner of the DCHP unit are both happy with the commercial arrangement that they enter into, NHH metering would be

acceptable. However for wide scale deployment of DCHP units the owner of the unit will need to see a real financial benefit and this will only be apparent if the sort of data provided by interval metering is made available.

Embedded genEmbedded genEmbedded genEmbedded generation means that a domestic property no longer fits the eration means that a domestic property no longer fits the eration means that a domestic property no longer fits the eration means that a domestic property no longer fits the standard domestic profile classstandard domestic profile classstandard domestic profile classstandard domestic profile class When very few micro generation units are installed this does not really present a problem, however as more system are installed the error introduced will

eventually become significant. Ilex estimate that this point will be reached when 33,000 micro-CHP units are in service.

There are two key issues facing the owners of DCHP units:

1. Currently. the quantity of power exported is relatively small so that its value is outweighed by the fixed costs of metering, settling and billing it. Suppliers are free to make payments for exports but, unless they can

themselves gain a value from the exports, this will be unsustainable as the market grows. If the Suppliers are to use or sell the exported power they must pass it through the Settlements process. Unless they are going

to provide subsidies to DCHP customers, they can only pass on the value of the exports minus their costs. For small quantities of exports this

figure can be negative. The key to releasing this value is to reduce the costs of metering and processing the export flows.

39 PT/06/BC1481/R

Page 39 of 56

2. Normally DCHP generators are heat led, this means that they only operate when there is a heat demand. The nature of domestic energy

consumption patterns is such that they tend to follow the occupation pattern of the property. That is, heating is normally only turned on when

the house is occupied and most power loads are initiated by the occupiers, and hence fall within the occupation periods of the property. This means that, generally, there is a coincidence between the heat and

power demands of a domestic property. Added to this, the heat demand is seasonal and peaks during the winter when power is more expensive in the wholesale market. There are two major consequences of this:

• The import power profile for DCHP owners is significantly and predictable modified.

• On average, DCHP units tend to produce power at periods of higher power costs.

At present there is no recognition that the import profiles of DCHP customers are different and the power imports of these customers are settled in the same way as other domestic customers. This implies that there is a lost value to the

DCHP customer (and Supplier) due to their revised profile not being recognised. In actual fact this benefit appears as a correction and the value is shared between all the Suppliers with customers in that GSP area.

In response to the former issue, Elexon have instigated a change to the

profiling system which allows the profile for an embedded generator to be modified29. This is referred to as Modification P81. This only applies to exports from properties with any embedded generator. Prior to the

introduction of P81 in 2003, all exports of any size had been required to be settled via the HH metering process. This was clearly uneconomic for small DCHP generators and effectively barred exports from these customers. P81

allowed NHH, quarterly metering to be used with an upper limit for generators of 16A/phase. This was revised upwards in 2004 to a total nominal capacity of 30kW per property.

To support P81 Elexon introduced a series of SSC’s, one each for DCHP, wind,

hydro and photovoltaics. These SSC’s were based on a limited number of profiles for the different technologies supplied to Elexon. For DCHP the export is deemed to occur for two periods every day, morning and evening. The

SSC’s were produced by ‘chunking’ an existing profile, Class 8, which is effectively flat throughout the day. The DCHP SSC is adjusted for BST to keep it in line with actual occupation patterns. Wind and hydro are assumed to be

flat throughout the year whilst photovoltaics are assumed to export through the middle of the day.

29 Elexon Change Proposal P81 'Removal of the Requirement for Half Hourly Metering on Third

Party Generators at Domestic Premises' Implementation www.elexon.co.uk

40 PT/06/BC1481/R

Page 40 of 56

This chunking process is already used for customers on switched tariffs, such as Economy 7. Here the Standard Settlement Class contains data on the

switching times to apply. The Settlement System can theoretically accept any number of SSC’s and the SSC may be made up of several different profiles

with different switching times. Although this process sounds crude, it is expected to greatly improve the

overall quality of the data in Settlements. Work is currently underway to develop the best fit for the switching times for this arrangement based on monitoring of a much larger population of embedded generators.30 This work

is expected to yield more accurate SSC’s but will not affect the basic approach to P81. A new Code of Practice (CoP 9) was introduced to define the metering requirements to support P81.

It should be noted that this approach only applies to kWh export register. The

imported energy profile is unaffected by P81 and is assumed to be as for any other domestic property.

As the number of different microAs the number of different microAs the number of different microAs the number of different micro----generation technologies increases, so wgeneration technologies increases, so wgeneration technologies increases, so wgeneration technologies increases, so will ill ill ill the number of different Settlement System Classes that are required.the number of different Settlement System Classes that are required.the number of different Settlement System Classes that are required.the number of different Settlement System Classes that are required.

The proposed approach to profiling will work in the short term where there are a limited number of different embedded generation technologies and equipment ratings available. However, as more systems are marketed with

potentially different generation profiles and different ratings (See Appendix A), the number of SSC’s will need to be expanded. For renewable micro-

generation the profile is likely be heavily determined by the weather and is therefore different again. The behaviour of wind and photovoltaics can largely be assumed to be independent of the manufacturer of the generator. This may

affect the total output but this is dealt with by the NHH meter register value. For DCHP, however, the situation may be much more complicated. The behaviour of the system will depend on the manufacturer of the generator, the

control system adopted, whether the system is fitted with a heat store and whether the generation is remotely scheduled. It might be possible to produce a series of SSC’s for each case but this could become very complicated and it

would require a considerable effort to derive and justify the different SSC’s

It is not possible to separate out the energy exported by one micrIt is not possible to separate out the energy exported by one micrIt is not possible to separate out the energy exported by one micrIt is not possible to separate out the energy exported by one microooo----generator.generator.generator.generator. It can be quickly appreciated that any difference between the profile class and

the actual energy consumed or exported at one site is lost in the profiling process. Any effort to change consumer behaviour to reduce load / increase generation at peak times is therefore smeared across all the suppliers, so there

is no incentive on any one supplier to drive changes in customer behaviour.

30 http://www.energy4enterprise.org.uk/events/beama.asp

41 PT/06/BC1481/R

Page 41 of 56

The consumer and the energy supply company are not rewarded with the true The consumer and the energy supply company are not rewarded with the true The consumer and the energy supply company are not rewarded with the true The consumer and the energy supply company are not rewarded with the true value of the generation when it isvalue of the generation when it isvalue of the generation when it isvalue of the generation when it is produced. produced. produced. produced. At times of peak system load it would make sense for the embedded micro-

generation to be operating. If excess energy could be exported to the distribution system it would make sense for the supplier and the customer to be rewarded accordingly. It would also make sense for all embedded

generation to be called to operate at times of peak demand, reducing the need to run the less efficient primary generating plant. In the current Settlements arrangements there is no mechanism for the owner of the generator to receive

the true market value of the energy they produce.

6.66.66.66.6 The Cost of SettlementsThe Cost of SettlementsThe Cost of SettlementsThe Cost of Settlements

The most important point to make about Settlement costs is that (due to the market structure introduced with supply competition in 1998) they include two rather different things:

• Firstly there is the cost of central settlements i.e. the charges that Elexon levies (under the governance of the BSC) to recover the costs of central

settlement activities. Elexon routinely publishes details of these charges. The rules are open to change through the Modification process, so if it did prove to be the case (for example) that the charging rules were a barrier

to using HH metering for micro-generation, any BSC Party could suggest changing them.

• Secondly there is the cost of Data Collection and Data Aggregation. Under the rules of the 1998 market, it is the Suppliers who appoint Data Collectors and Data Aggregators, and the charges are therefore open to

negotiation between the two parties. There is therefore no transparent mechanism to identify what these charges are.

Although the actual charges are unclear the general consensus is that it is not cost effective to settle smart meters for domestic premises in the half hourly market; it is better to leave the meters in the NHH market, and then to use the

additional information provided by the meters within the Supplier’s proprietary billing systems.

Part of the problem lies with the way that the Data Collector recovers their fixed costs. There are only 100,000 HH meters (as apposed to 25 million NHH

meters). The cost per MPAN is therefore higher and as this is passed on to the Suppliers, acts as a barrier to using HH metering in applications where the volume of energy is low.

42 PT/06/BC1481/R

Page 42 of 56

6.6.1 Costs of Central Settlements

Elexon’s charges for central settlements represent only a part of the overall “settlement” cost.

Most central settlement costs are recovered from the BSC Parties in proportion to their total volume of metered energy i.e. regardless of what sort of meter

they use. However there are some specific charges, including in particular:

• A charge of £50 / month for each CVA Metering System

• A charge of £1.25 / month for each Half Hourly metering system in SVA.

Note that these two costs are not directly comparable as the CVA costs include data collection whilst the SVA costs do not.

There are no BSC charges for NHH metering; the charges are levied solely by the Supplier Agents such as the Data Collector and Data Aggregator.

If the meter is registered for HH Settlement in SVA, then the annual charge will be:

12 months x £1.25 / month = £15 / annum 6.6.2 Charges Levied by Data Collectors and Other Supplier Agents Half HourlyHalf HourlyHalf HourlyHalf Hourly

Typically, a supplier will charge a consumer a monthly fee for Half Hourly Data Collection and Data Aggregation. This fee is made up of various elements

including:

• Data Collection

• Data Aggregation

• Settlements

• Annual Site Safety Visit

• DTN Charges

• Agent Administration On a consumer’s bill the cost for this basket of services can vary from between £18 per month to £50 per month. Most suppliers’ charges are at the lower end

of the scale. Agent charges for the DC and DA elements fall within a relatively narrow band either side of £14 per month. The variations consumers may

observe on their bills are down to individual supplier pricing policies. A site with both an import and export MPAN will pay double the above.

43 PT/06/BC1481/R

Page 43 of 56

Non Half HourlyNon Half HourlyNon Half HourlyNon Half Hourly

The fee for NHH metering is made up of the following components:

• Data Collection

• Data Aggregation

• Meter Asset Provision

• Meter Operation

• Settlements

• Bi-Annual Site Safety Visit

• DTN Charges

• Agent Administration. In this market it is extremely difficult to identify what a consumer is paying for

these services. This is because the charges are rolled-up into the unit costs and so are not transparent.

The following set figures have been gleaned from discussions with Meter Operators, Non Half Hourly Data Collectors and Suppliers.

NHH Quarterly billed - £15 to £20 per annum NHH Monthly billed - £60 to £85 per annum.

6.76.76.76.7 BillingBillingBillingBilling

At the heart of any energy Supplier’s business is the billing and customer

management system. This will typically hold details of several million customers and will be expected to produce accurate bills based on actual and estimated meter readings. Considering the amount of data handled, great

store is placed on the accuracy of the information held and the processing of that data.

Unfortunately, there are many stories in the press of the problems that customers have with incorrect or missing bills, mislaid payments and

difficulties in changing suppliers. The Supply companies take these complaints extremely seriously and continue to work very hard to minimise them.

Considering the size and complexity of the billing systems and the sensitivity of any changes made to the systems, changes are not made unless there is a

compelling business case. A significant change may cost several million pounds to implement.

When the original billing systems were first developed, energy was not generated or exported by domestic customers. The systems therefore did not

have the functionality required to deal with energy exports and it is

44 PT/06/BC1481/R

Page 44 of 56

understood that this is part of the reason why very few Suppliers offer to pay homeowners for the energy exported from a DCHP unit.

45 PT/06/BC1481/R

Page 45 of 56

7777 STASTASTASTAKEHOLDERSKEHOLDERSKEHOLDERSKEHOLDERS

7.17.17.17.1 Government and Regulatory BodiesGovernment and Regulatory BodiesGovernment and Regulatory BodiesGovernment and Regulatory Bodies

7.1.1 DTI The Department of Trade an Industry has ultimate responsibility of the energy industry. Most governance of the energy industry is ultimately derived from

various Electricity, Gas and Energy Acts and associated Statutory Instruments. In general, these point towards detailed rules elsewhere. In particular, governance of utility electricity meters is based on the 1989 Electricity Act,

Schedule 7. This states that the Supplier shall provide an appropriate certified meter and that the Supplier is responsible for keeping the meter in good order

for registering the consumption of electricity by the customer.

7.1.2 Ofgem

Along with the privatisation of the energy industry, the DTI has devolved its management of the industry to the Gas and Electricity Markets Authority,

which in turn, delegates day to day operation to the Office of Gas and Electric Markets (Ofgem). The objectives of Ofgem are set by the government but, beyond this, the government has little direct control over the Industry.

The following extract from the Ofgem website explains the regulator’s role:31

“Protecting consumers is Ofgem’s first priority. We do this by:

• promoting effective competition, wherever appropriate, and

• regulating effectively the monopoly companies which run the gas pipes and the electricity wires.

We have other priorities too. We:

• help secure Britain’s energy supplies by promoting competitive gas and electricity markets - and regulating so that there is adequate

investment in the networks

• help gas and electricity markets and industry achieve environmental improvements as efficiently as possible

31 As stated on the Ofgem web site

http://www.ofgem.gov.uk/ofgem/shared/template1.jsp?assortment=/aboutofgem/ourwork (28th

Nov 2005):

46 PT/06/BC1481/R

Page 46 of 56

• take account of the needs of vulnerable customers, particularly older people, those with disabilities and on low incomes”.

Ofgem has a fundamental assumption, which is that the lowest costs for delivering any service are achieved by introducing effective competition. In

line with this, Ofgem has been driving the unbundling of metering services. It has broken the industry into a number of separate roles; meter ownership, meter operation and data collection. The intention of Ofgem is that these

should all be provided as separate services in a competitive market. In reality it has proven difficult to achieve the reality of competition, owing to the entrenched position of some of the market players.

Ofgem controls the industry via a series of Licences that all companies working in these controlled areas must sign and comply with. These take the

form of Supply, Generation, Transmission and Distribution Licenses. Any company wishing to work in these areas must get a Licence from the Authority

and, once gained, comply with its terms. It is by the terms of the Licence and changes to these that Ofgem manages the Industry. It should be noted that the small generators being considered in this report fall below the threshold

required for a generation Licence. Ofgem recognises that there are competitive and monopoly businesses within

the energy supply industry. It regulates the monopoly businesses and manages the market structure for the competitive areas. Where possible, Ofgem avoids regulation and prefers to allow industry to self regulate. Within

this project, the main roles are all considered to be competitive. Hence, Ofgem would expect to take little regulatory action in these areas. If it were

persuaded that the market was not working correctly, it could take action to deal with this. Additionally, if the government made changes to its terms of reference to add to or rebalance its objectives, it would then be empowered to

act to achieve this. 7.1.3 Elexon On privitisation of the Electricity Industry in 1989, it was necessary to create a commercial structure to support the transactions between all parties;

Suppliers, Generators, Distributors and Transmission companies. It was also necessary to decide which of the generators should be called up at each half

hour period. Initially the scheduling of generation was based on the CEGB’s old Pool arrangements. The principle behind this was that, at every half hour period, as the demand went up or down, the cheapest available plant would be

added or the most expensive withdrawn from the network. This arrangement was changed with the NETA (New Electricity Trading Arrangements) system. In this, Suppliers were permitted to make fixed contractual arrangements with

Generators for the purchase of power. To deal with differences between what Suppliers had contracted for and actual demand, a balancing market was set

47 PT/06/BC1481/R

Page 47 of 56

up where companies could buy or sell excess power to balance their load or output. This was recently revised as BETTA (British Electricity Trading and

Transmission Arrangements) when Scotland was brought into the same set of arrangements as England and Wales.

Ofgem delegated the management of these arrangements to Elexon. All parties to the trading arrangements agree to be governed by the Balancing and

Settlements Code (BSC). Part L of the BSC is devoted to metering. Cascading from the BSC are a number of Codes of Practice and Procedures (the Code Subsidiary Documents) that deal with the specific details of the working of the

industry. Elexon has a process for making changes to the BSC and the Subsidiary

Documents. This usually involves a signatory to the BSC proposing a modification. Agreement then has to be reached on funding the work required

to develop the proposal. Elexon is not able to launch its own modifications and there is a basic assumption that funding should be proportionate; i.e. the cost of developing a modification should bear some relationship to the

number of customers affected or its cost benefit. Once investigation of a modification is agreed an expert group is set up with

representation from all stakeholders. This group will develop a recommendation that is then reviewed by signatories to the BSC. If agreed this will then be adopted under the BSC.

Elexon would believe itself to be neutral with regard to modifications, as its

role is to facilitate the operation of the BSC in the interests of its members. It is worth noting that, both for Elexon and Ofgem (where it is acting in the competitive market), there is a desire to reach consensus across the industry.

Given the diversity of Stakeholders affected by some developments, this can be an ambitious target and can tend towards maintaining the status quo because one or a few stakeholders can effectively veto new proposals.

7.27.27.27.2 Other StakeholdersOther StakeholdersOther StakeholdersOther Stakeholders

7.2.1 The Electricity Supplier and micro-Generator Supplier

The electricity supplier and micro-generator supplier both have a vested interest in making sure that the end user is correctly charged, or reimbursed

for the electricity they use or generate. For example, Powergen Retail intends to install over 50,000 micro-CHP domestic generators over the next 5 years. In

order for the full benefit to be gained from these units the customer must be fairly rewarded for electricity generated. Powergen Retail’s main objectives are to support micro generation while fully exploring any wider possibilities.

There are many areas where advanced metering may add value outside of the micro-generation domain. Advanced metering would enable Powergen Retail

48 PT/06/BC1481/R

Page 48 of 56

and other supply companies to offer innovative tariffs, thereby encouraging customer loyalty and facilitating energy efficiency initiatives.

Supply businesses will also be considering the impact of the recent Ofgem

consultation. Introducing advanced metering, whether this is truly “smart” or just involves AMR, there are potentials to influence customer behaviour. Powergen Retail has recently trialled customer energy statements which detail

a customer’s usage over the period of a year. The statement gives total energy usage for each of the four annual billing quarters and compares the totals to those for the previous year. It is hoped that these statements will highlight the

consumers’ energy usage and consequently encourage them to conserve where possible. Advanced metering would allow an extension of this concept, where consumers would be provided with energy statements for each billing

period showing their typical daily profile, highest and lowest demands, night time base level and weekend usage, along with advice on how energy savings

may be made. As micro-generation is still at an early stage of development, it will be

important for the equipment manufacturer and supplier (whether that be the electricity company or a third party) to manage their fleet of appliances. This implies that some form of status or condition monitoring will be required.

There are obvious benefits if this can be integrated with the meter data as new metering will need to be installed along with the micro-generation equipment. Whether the meter acts as the central data collection hub, or just relays meter

data to a separate data collector is less important, as long as the data is available.

7.2.2 End Users

The end user will want to satisfy their heating and electricity demands from the most economic means, with minimum impact on the way they live. It is not necessarily so important for most customers that they are also operating in

the most environmentally efficient manner. This means that the micro-generation equipment needs to deliver the greatest financial benefit (i.e. exported energy is fully rewarded) and is reliable and being maintained when

it is needed. Both demands can be met with smart metering, although it is not strictly necessary for half-hourly metering to be installed.

According to a recent survey by Uswitch.com technical jargon on bills baffles customers. The survey found that customers who receive separate bills for

gas and electricity are more likely to be confused by their bills, and that over two thirds of those surveyed do not understand how the final tally is arrived at or even what a kWh is. Several issues were highlighted as being in need of

improvement, customers would like a clearer indication of the meter reading dates, how the price relates to use and where the bill has been estimated.

49 PT/06/BC1481/R

Page 49 of 56

A long-term trial of service aggregation by organisations associated with TAHI32 (The Application Home Initiative) entitled “Smart” reported to the DTI in

June 2005. The objective of the Smart trial was to observe the resultant effect on consumption of providing consumers with real-time data on their energy

usage. The trial utilised remote metering technology and standard digital television as the display medium. 1,500 households in the Leicester area were invited to participate in the trial, they were also offered free broadband internet

and a digital set-top box for taking part, however, only 50 responded and of these a mere 20 were deemed suitable for the trial. The trial successfully demonstrated the technology but also highlighted the high level of apathy

among consumers towards such products. Initial feedback indicates a suspicion of such technology and its “big brother” nature.

7.2.3 Meter Operators

There are several significant issues which affect the Meter Operators, the first of which is the roll out strategy. As the number of automatically read meters increases the density of dwellings requiring meter-reader visits in any given

area decreases, making it more difficult to plan routes and reading strategies in a cost effective way. Thus the cost of an automatic read will not only be higher, but it will also push up the cost of conventional reads.

However, some longstanding issues may be resolved by the introduction of wide scale Advanced Metering, primarily the struggle to attain read targets but

also the stress that monthly reads put on the cycle. As they must all be read within a five day period for accounting purposes monthly reads traditionally

put a severe strain on the system. However neither of these issues is likely to be affected by the installation of advanced meters on dwellings with domestic CHP.

There are also concerns in the industry about stranded assets. At present the low value of standard functionality meters means that customers changing

supplier do not create an issue, if however the customer has just had a sophisticated piece of metrology and communications hardware installed on their property free of charge the ownership of that asset becomes a real issue

if they choose to change supplier.

7.2.4 The Distribution System Operator

Half hourly, remotely read meters on embedded generation sites could allow the DNO (Distribution Network Operator) to operate their network more

efficiently. At present, the only permanent periodic system load measurements are half hourly load readings from Primary 11kV feeder

breakers and HH meters on large supplies. It is possible to install temporary equipment to measure loads at other sites as required, but the provision of

32 www.theapplicationhome.com

50 PT/06/BC1481/R

Page 50 of 56

load information from half hourly metering could be more useful. This is because the measuring techniques described cannot identify where

contributions from small scale generation exist, they appear merely as an absence of load. As the penetration of small scale generation increases this

will become more important, without this metering information their contribution will be overlooked. The value will depend on whether the information is available on demand or is only downloadable periodically (e.g.

monthly or daily). While historic HH load information will allow reinforcement schemes to be

more effectively planned, on demand information would facilitate temporary backfeeds for maintenance. If immediate pre-fault load information could also be retrieved following an outage it could be used to improve restoration

strategies. However, this would rely on an additional power source on site which may not be an advantage if it required maintenance (e.g. battery

replacement).

51 PT/06/BC1481/R

Page 51 of 56

8888 THE WAY FORWARDTHE WAY FORWARDTHE WAY FORWARDTHE WAY FORWARD

It is widely anticipated that all properties will eventually be fitted with ½ hourly meters. This ultimate aim remains some way in the future; even if the

economic case could be made now, it would take at least 10 years for the current stock of meters in service to be replaced.

Before ½ hourly meters are installed in the majority of domestic premises the costs of equipment, communication, data processing and Settlements will all need to reduce considerably.

In the meantime there is a need for interim solutions for the requirements of householders installing DCHP units.

Two issues need to be addressed, allowing exported power to be rewarded

and allowing customers to be rewarded for their modified import profile. Additionally it is worth considering the implications if microCHP is brought within the Energy Efficiency Certificates scheme, in which case it is likely that

there would be a need to meter the generation output. 8.18.18.18.1 Short Term SolutionShort Term SolutionShort Term SolutionShort Term Solution

Exported Energy

With regard to the export of power, the current situation is that it is too

expensive to meter and settle the exported power under P81, leaving no value for the Suppliers to return to the customer. It seems unlikely in the short term that this problem would be improved by extending HH metering to exports as

this could only increase costs at this time. Also, the current arrangement of profiling is a reasonably accurate reflection of the exported power (unlike the

imported power), so that there would be little additional value from HH metering of export.

Thus the need is to reduce costs. A number of ways of achieving this have been examined by the Suppliers. Currently the proposal favoured by some Suppliers is that the MPANs for the import and export registers on the meters

should be combined and governed by a single contract between the Supplier and the customer. This would have the benefit of reducing the transaction costs of servicing the customer account. Additionally, the Suppliers would be

able to absorb the extra costs into the whole income stream associated with the customer, increasing their value to the Supplier. To avoid charges of

forcing customers into such joint contract they could be left with the option of taking a split import/export contract but, given the higher costs of servicing such a customer, it can be assumed that there would be a lower payment to

the customer and they would be unlikely to opt for this choice.

52 PT/06/BC1481/R

Page 52 of 56

Imported Energy

With regard to realising the value of the modified import profile, in the short term, it is suggested that a system be set up which operates outside the

Settlements process, in a similar fashion to Renewables Obligation Certificates.

In this scenario, a ½ hourly, import / export meter with remote communications facilities is installed at the commercial boundary. The meter is registered as normal in the Settlements system, however half hourly import

and export data is then collected by the Supplier using their own systems. In order for the data collection charges to be minimised meter data would have to be collected through a system such as ADSL broadband – other systems

including PSTN, SMS, GPRS and GSM modems will all be prohibitively expensive. For example, service costs associated with providing ½ hourly

interval data for both import and export channels on a daily basis via SMS are likely to be in the order of £48 to £60 per annum.

It would then be possible to compare on a ½ hourly basis the actual energy flows, and the value of that energy, with that derived by the profiling system.

Any difference between the two values could then be settled separately – either as a correction to the suppliers’ payments, or more simply from a separate fund administered by Elexon or Ofgem. In future, as the size of the

micro-generator increases, so too will the value of the exported electricity. HH metering and Settlement of the exported energy, using the model described

above will then become viable. Suitable controls and audit trails would obviously need to be put in place, but

this solution offers a relatively simple and low cost method by which the true value of the embedded micro-generation can be realised.

The metering and communications arrangements provided in this situation could be readily extended to include for metering of the generator output, should the EEC3 33 measures include microCHP.

8.28.28.28.2 Medium Term SolutionMedium Term SolutionMedium Term SolutionMedium Term Solution

In the medium term, the value of the reconciliation payments described above will become significant and an alternative will be required. One of the greatest

obstacles to be overcome will be the quantity of data that needs to be transmitted and processed if every meter records ½ hourly energy flows. Rather than transmitting 48 half hourly values every day from the meter to a

central data collector, it may be more appropriate to carry out some of the processing on the meter. Options include:

33 Energy Efficiency Commitment. www.ofgem.gov.uk

53 PT/06/BC1481/R

Page 53 of 56

• The meter selecting which profile class to apply, choosing from perhaps 50 standard profiles, and then transmitting on a daily basis, the meter advance and profile.

• The meter providing switching times to obtain a best fit between the measured energy flow and the standard profiles.

• It may be possible to aggregate the outputs from a large number of DCHP units and combine them into a single ‘virtual’ power plant of much larger size. If the HH data from all of the generators could be collected and

assembled into a single HH profile, this might be settled via the HH Settlements process, the cost of this being shared amongst the

contributors. If it proved to be difficult to obtain the data with the daily time window an alternative HH settlement scheme that was introduced in 1989 could be used. This allowed for data to be provided outside of the

daily data deadlines and was supported by Code of Practice 6. It never achieved popularity and has not been used but could be revisited for this application.

54 PT/06/BC1481/R

Page 54 of 56

8.38.38.38.3 TimescalesTimescalesTimescalesTimescales

A timeline for the short, medium and long term solutions is suggested in the following figure.

Figure Figure Figure Figure 2222:::: PotenPotenPotenPotential Timeline for Metering Developmentstial Timeline for Metering Developmentstial Timeline for Metering Developmentstial Timeline for Metering Developments

8.48.48.48.4 Enabling Activ itiesEnabling Activ itiesEnabling Activ itiesEnabling Activ ities

8.4.1 Micro-Generation Obligation In order for the proposed solutions to be developed some level of intervention

will be required by the Government. Initially it is recommended that a new financial arrangement – the Micro-Generation Obligation – be put in place to

- 2

years

Now

2007

2010

2050

Quarterly Readings � Profiling � Standard Domestic Import Nett Generation

P81 � Quarterly Readings � Standard

Domestic Import Chunked Export Profile

Full local record of ½ hourly data + on-board storage

� Data provided to supplier directly or via a Data Collector

� Difference between the Settlements Profile ½ hour value and actual metered ½ hour value reconciled “outside” the

Settlements System � Possible Government incentive – cf. ROCs

Local Profile Generation � Each meter provides SSA with profile

class � EAC Advance x Profile passed to ½ hourly

SVA system

Or � Chunked profile used and meter provides

details of switching times to SSA

Wide scale introduction of “smart” metering on

rolling programme – creates

base level of

functionality

Potential Developments in Metering and Settlement Potential Developments in Metering and Settlement Potential Developments in Metering and Settlement Potential Developments in Metering and Settlement Process for Domestic MicroProcess for Domestic MicroProcess for Domestic MicroProcess for Domestic Micro----GenerationGenerationGenerationGeneration

Increasing communications bandwidth:

SMS GPRS Cheap Wireless BT VOIP

Power Line Carrier

55 PT/06/BC1481/R

Page 55 of 56

reward suppliers and homeowners who operate DCHP units. There is precedent for this arrangement in the existing arrangements under the

Renewables Obligation.

8.4.2 Communications Longer term take up of ½ hourly metering will depend on the costs of the

communications and Settlements systems being reduced. Power Line Carrier has the potential to provide cheap and universal communications medium, once the initial capital costs are overcome. PLC also has the advantage over

PSTN and ADSL technologies that it will not rely on the homeowner to maintain the communications channel. However, with the existing distribution system arrangements it is difficult to see how a national network will develop

without external intervention.

This intervention may be in the form of a light touch – agreeing communication standards, technologies and commercial frameworks for access to, and interoperability between, different DNO systems. At the other

extreme, an obligation could be placed on the DNO to provide a PLC network as a condition of their Licence.

8.4.3 Cost of Settlements The cost of the Settlement System for HH meter data is generally seen as an

impediment for NHH metering to be replaced with HH meters. It is not clear that there is a case for all NHH energy to be traded through the HH Settlements

System, however once there is a significant population of installed micro-generation units it may well be appropriate for these systems to be entered into HH Settlements. The Settlements charging arrangements will have to be

reviewed before this can take place.

56 PT/06/BC1481/R

Page 56 of 56

9999 GLOSSARYGLOSSARYGLOSSARYGLOSSARY

ADSL Asymmetric Digital Subscriber Line AMR Automatic Meter Reading

BETTA British Electricity Trading and Transmission Arrangements BSC Balancing and Settlements Code DNO Distribution Network Operator

DR Data Retriever EEC Energy Efficiency Commitment GSM Global System for Mobile communication

HH Half Hourly HV High Voltage kWh kilo-watt hour

LAN Local Area Network LV Low Voltage

MOA Meter Operator Agent MPAN Meter Point Administration Number NETA New Electricity Trading Arrangements

NHH Non-Half Hourly PLC Power Line Carrier PSTN Public Switched Telephone Network

SCADA Supervisory Control and Data Acquisition SIM Subscriber Identity Module SMS Short Message Service

GPRS General Packet Radio Service WAN Wide Area Network

HHDC Half Hourly Data Collector CSD Circuit Switched Device SSC Standard Settlement Class

TAHI The Application Home Initiative

PT/06/BC1481/R

Page 1 of 1

A-1

Appendix A Appendix A Appendix A Appendix A ---- Summary of Emerging Micro Summary of Emerging Micro Summary of Emerging Micro Summary of Emerging Micro----CHPCHPCHPCHP Generation Technologies Generation Technologies Generation Technologies Generation Technologies

Product NameProduct NameProduct NameProduct Name TypeTypeTypeType Electrical Electrical Electrical Electrical Output (kW)Output (kW)Output (kW)Output (kW)

Thermal Output Thermal Output Thermal Output Thermal Output (kW)(kW)(kW)(kW)

Potential Potential Potential Potential Launch DatLaunch DatLaunch DatLaunch Dateeee

Ecowill Gas Engine 1 3.25 2003

Baxi PEM Fuel Cells 1.5 2.75 2012

Ebara Ballard PEM Fuel Cell 1 1.7 2008

Vaillant PEM Fuel Cell 4.6 5.6 2012

Baxi Rankine Cycle 1 8 2008

Climate Energy Rankine Cycle 3 25.5 2010

Cogen Micro-systems

Rankine Cycle 2.5 11 2011

Otag Rankine Cycle 3 16 2009

Acumentrics Solid Oxide

Fuel Cell

2 1.3 2012

Ceramic Fuel Cells

Solid Oxide Fuel Cell

1 1 2010

Ceres Power Solid Oxide Fuel Cell

1 1.3 2011

BG MicroGen Stirling Engine 1.1 4 2007

Disenco Stirling Engine 3 9 2010

Enatec Stirling Engine 1 7 2008

Stirling Systems

Stirling Engine 1.2 5 2010

WhisperGen Stirling Engine 1 7.4 2005

PT/06/BC1481/R

Page 1 of 3

B-1

Appendix B Appendix B Appendix B Appendix B –––– Summary of SVA Da Summary of SVA Da Summary of SVA Da Summary of SVA Data Interfacesta Interfacesta Interfacesta Interfaces

PT/06/BC1481/R

Page 2 of 3

B-2

PT/06/BC1481/R

Page 3 of 3

B-3

PT/06/BC1481/R

Page 1 of 1

C-1

Appendix C Appendix C Appendix C Appendix C –––– Load Profiles and Their Use in SettlementLoad Profiles and Their Use in SettlementLoad Profiles and Their Use in SettlementLoad Profiles and Their Use in Settlement

Paper provided by Elexon, with thanks to John Lucas and Jon Spence. The original document is available in the FAQ section of the Elexon web site

(www.elexon.co.uk), under the Elexon Helpdesk pages.