nanogrids for home application in a power cloud framework

NanoGrids for Home Application in a Power Cloud Framework D. Menniti, A. Pinnarelli, N. Sorrentino, A. Burgio, G. Brusco, V. Frascà, L. Mendicino, and M. Mercuri

Department of Mechanical, Energy and Management Engineering (DIMEG)University of Calabria Via Bucci 42C, Arcavacata di Rende - CS, Italy

The paper shows the higher economic benefit a prosumer may reach when he adopts a nanogrid in a Power Cloud framework instead of in a stand alone framework.

Summary

A nanogrid for home applicationNanogrids are small dc microgrids (generally not over 5 kW) which typically serve a single building or a single home. The nanogrid interconnects generation units and plants (PV, micro-CHP Stirling-engine, gas micro-turbines, fuel cells, etc.) and electric storage systems. Micro-sources, storage systems and loads are connected to a common dc bus through appropriate power converters.

The Power Electronic Interface (PEI) is a bidirectional power converter that regulates the power flow between the nanogrid and the grid. The PEI allows the nanogrid to operate as a single system, providing ancillary services to the grid. IEC 61850-720 communication is available.

Power Cloud as a model

Power Cloud is a management and business model applicable to the Integrated Community Energy Systems (ICESs) that is locally and collectively organized energy systems.

Power Cloud is a feasible solution for put in practice the concept of sustainable energy communities, community energy systems, micro-grids community, and peer-to-peer energy.

Urban and rural areaA PV system on the rooftop is an easy and cost-effective way to independently fulfil a part of own electricity demand, reduce the electric bill, generate savings, contribute to the exploitation of renewable energy sources, and contribute to the environmental preservation by reducing the greenhouse gas emissions. Such an opportunity is evidently reserved to those users which have ample space for installing a PV system; on the contrary, it is denied to those users which, as an example, live in apartment building.

Local demand Remote demand

Local demand Remote demand

Power Cloud for social development

Citizens may produce energy and participate in the electricity market, selling energy to the formers. The electricity market is accessible to all citizens that become real market operators in aggregate form. Such a transformation would have an immediate economic return, relying on price margins that exist between the wholesale and retail prices.

Citizens in urban area and those in rural area are joined in a process of social development where exploiting RESs and self-consumption are two main pillars.

Citizens in rural area, which have large area, oversize their PV plants so to generate electricity for those living in the downtown and which cannot install a PV plant on rooftop.

Members of Power CloudMembers are:

Simple Generation Systems Power Cloud Consumers Power Cloud Prosumers

Members are managed by the aggregator, i.e. Community Energy Provider (CEP), which is a no-profit entity which legally represents the community. The CEP is the power dispatcher. The CEP interfaces the Power Cloud and the market /system operators. The CEP ensures the functionalities of the whole system.

Simulating the Power CloudNumerical experiment were carried out so to calculate a feasible Power Cloud. Below four fundamental rules which have been adopted for simulating power cloud.

1. The electricity not self-consumed by prosumers is given to power cloud for free (export price is zero);

2. The cost-free electricity provided by prosumers is sold to consumers at a discounted price (25% less than the PE i.e. price suggested by the authority each 3 months )

3. The cost-free electricity provided by prosumers and not sold to consumers is sold to the wholesale market (zonal price);

4. The electricity price paid to simple generation systems is 5% higher than the zonal price;

5. The electricity cost for the prosumers is the PE.

Prosumers Consumers Simple generation systems

The consumer/prosumer type

3kW contractual power5621 kWh/year

3kWp PV plant, 1400 €/kWp

3kW-3kWh EESS, DOD_lead 50%, DOD_lithium 30%, RTE 80%, tax deduction equal to 50% of the investment costs spread over 10 years

5kW nanogrid, …….

A consumer


A prosumer

How much it costs????

PV plant placed in Southern Italy (PVGIS)

Nanogrid cost: a prototypeA 3.3kW prototype of a 3-phases nanogrid has been designed and built in the laboratory of Electric Power Systems and Renewable Energy Sources (LASEER).The prototype to implements the innovative business/management model of Power Cloud. The prototype is able to move the user from “Consumer” to “Prosumer”, from “business as usual” to “power cloud”. For the real time control, the prototype adopts the dc bus signalling (DBS) control strategy. The DBS control strategy has been implemented in a prioritized fashion so to maximize the use of renewables and to maximize self-consumption.

The consumer/prosumer type


3kWp PV plant, 1400 €/kWp

3kW-3kWh EESS, DOD_lead 50%, DOD_lithium 30%, RTE 80%, tax deduction equal to 50% of the investment costs spread over 10 years

5kW nanogrid, 4300€_lead, 5000€_lithium

A consumer


A prosumer

PV plant placed in Southern Italy (PVGIS)

Two alternative frameworks

Power Cloud Framework

1) Can you go into debts?

2) Are you a credit worthy customer?

3) Will your income be so high in the next 10 years to release off tax

deduction?

Stand Alone Framework1. Contact the Power Cloud;2. Adhere to Power cloud;3. Enjoy the installation of your PV, EESS,

Nanogrid;4. Pay preferential tariff for electricity bill

and installment;5. Do not release any Tax deduction;6. Export your electricity at 0 €/MWh.

1. Go to Bank and ask for a loan (9 %, 20 years);2. Complete administrative procedures;3. Install PV, EESS, Nanogrid;4. Pay bill and installment;5. Release Tax deduction for 10 Years;6. Export your electricity at 39 €/MWh.

1

2

3

No

Yes

Yes

No

No

??

Yes

Time interval Cost/year [€] Cost [€] Saving [€]

Business as usual 0-20 1392,67 27853,40 0,00

Lead EESS without tax deduction

0-10 1773,60 22546,00 5307,4010-20 481,60

Lead EESS with tax deduction *

0-10 1348,69 18296,90 9556,5010-20 481,60

Lithium EESS without tax deduction

0-101829,9 22618,50 5234,90

10-20 431,95

Lithium EESS with tax deduction *

0-10 1369,95 18019,00 9834,4010-20 431,95

Stand alone framework

* tax deduction equal to 50% of the investment costs spread over 10 years.

Choice 0

Choice 1

Choice 2

Choice 3

Choice 4

Time interval Cost/year [€] Cost [€] Saving [€]Bussiness as usual 0-20 1392,67 27853,40 0,00

Stand alone and Power cloud framework

For all those users which cannot chose the stand alone framework Power cloud allows them to achieve almost equal saving. Cost/Year is obtained as sum of:

• Bussiness as usual: 1392,67 = 1138,47 + 254,20• Stand alone: 1369,95 = 412,10 + 60,70 + 1398,50 – 460,00 – 41,35• Power Cloud: 1323,00 = 412,10 + 60,70 + 850,20 – 0,00 – 0,00

Installment in Power Cloud reduces because 1) the price for a nanogrid reduces from 5000 € to 3000 € due to economies of scale 2) the loan lenght reduces from 9% to 2% when Power Cloud is put in practice by Public Administration.

(EG) (Tax) (Inst) (Deduc.) (ExP)

Lithium EESS with deduction

0-10 1369,9518019,00 9834,40

10-20 431,95

Lithium EESS without deduction

0-10 1323,0017958,20 9895,20

10-20 472,82

A feasible Power cloud

Gestore dei Mercati Energetici (GME): costs due to the access for the exchange energy platform and energy trading fees; b) Terna (TSO): costs due to guarantees, dispatching and real time power imbalances; c) Distribution System Operator (DSO): energy transport and system charges; d) Agenzia delle Dogane e Monopoli (ADeM): excise duty; e) Aggregator: daily operations of PC management such as the billing system, measurement, software, personnel and general expenses.

A Power Cloud of 4037 members has revenues from the energy sale to the 1011 users and to the whosale market; these revenues are 300 000€ and they balance the costs.

A feasible Power Cloud as 4037 members. Among members, 1011 of them have not a nanogrid, any PV plant, any EESS; they buy electricity from Power Cloud and benefit of a discount of 25% on electricity price. Among them, 3025 of them have a nanogrid, a PV plant and an EESS; they buy and sell electricity inside the power cloud to members and outside to the whosale market. It remains 1 member with an equivalent 9 MW PV plant.Why a Power Cloud of 4037 members?

The Power Cloud is a no-profit organization. A Power Cloud of 4037 members has costs; these costs are estimated being 300 000 € (about 75 € member/year.

ConclusionThe paper demonstrated the higher economic benefit a prosumer may reach when he adopts a nanogrid in a Power Cloud framework instead of in a stand alone framework.

A Power Cloud framework also:- allows a wider spread of electricity storage systems – so to maximize the self consumption – preventing incentive policies from Governments.

A Power Cloud also favorites:- the exploitation of renewables sources;- the economic growth of less-affluent Regions;- the participation and the involvement of citizens;- the reinforcement of schemes of mutual support.

Thank you for your attention

D. Menniti, A. Pinnarelli, N. Sorrentino, A. Burgio, G. Brusco, V. Frascà, L. Mendicino, and M. Mercuri

Department of Mechanical, Energy and Management Engineering (DIMEG)University of Calabria Via Bucci 42C, Arcavacata di Rende - CS, Italy