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Renewable Energy and Case

Studies

13 December 2013

Presentation Outline

� Energy Overview

� Renewable Energy Application in Hong KongSolar Water Heating System

Solar Photovoltaic (PV) Panels System

Wind Turbine

� Considerations for On-grid or Off-grid RE System

� Case Study - Town Island

� Renewable Energy Application in Worldwide

Energy Overview

Energy Resources

�Fossil Fuel: Coal , Oil & Gas

�Nuclear

�Renewable Energy

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Fossil Fuel: Coal

� Anthracite (無煙煤) : 85% C, 5% volatile matter

� Bituminous

� Sub-bituminous

� Lignite (brown coal) : 30% C, 25% volatile matter

Fossil Fuel: Oil & Gas

� Petrol/gasoline/kerosene

� Diesel/Heavy Oil

� LPG, Natural Gas

� LNG

Nuclear

� Fission : Uranium 235, Plutonium 239

� Fusion (under research)

� E = mc2

Renewable Energy

� Solar, Wind, Hydropower, Geothermal (地熱), Biomass (生物質能), Ocean (海洋能 : wave, tidal, current), biofuels (e.g. biodiesel, ethanol), …

� Derived from natural processes that are replenished constantly

� Derives directly or indirectly from the Sun or heat generated deep within the Earth

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World Total Primary Energy Supply

Remark:o Information from International Energy Agency (IEA)o Mtoe = Million Tonnes of Oil Equivalent

RE12.5% ~ 764 Mtoe

RE13.3% ~ 1744 Mtoe

World Electricity Production

Remark:o Information from International Energy Agency (IEA)

RE21.6% ~1321 TWh

RE20.3% ~ 4492 TWh

Observations from Energy Statistics

� Fossil fuels ~ 80% worldwide TPES

� WEP, RE electricity = 20.3% of total

� By far, hydropower is the major RE

Fossil Fuels ?

� Emission of Green House Gas (GHG)

� Global Climate Change

� Local/Regional Pollution

� Air Quality Problem

� Depletion of Reserves

���� Stone Age?

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Renewable Energy ?

� Climate friendly: GHG free or neutral

� Clean: low or no pollutant for certain RE

� Unlimited resources

� Remote/off-grid

� Education/Tourism

� Local jobs

� Life style

Solar Energy

Sun & Earth

109 x D D = 12742km

S = 149.6 x 106 km

Time Travel by Light Speed ~ 8’19”

Solar Intensity = 1361 W/sqm

Surface Temp = 5505 deg.C

Sunlight at outer atmosphere = 1.366 kW/m2

(the Solar Constant)

Solar energy incepted by the Earth ~ 4.15 x 1015 kWh/day

World electricity production in 2011 = 2.21 x 1013 kWh (0.5% of 4.15 x 1015 kWh)

Variation of Solar Energy

� Time of the day

� Day of the year

� Latitude at the observing point

� Angle between normal of the surface and the Sun

� Atmospheric conditions

� Shading from nearby structures

Wind Energy

� Air flow: uneven heating by the Sun, self-rotation of the

Earth

� Prevailing: Trade Wind, Monsoon

� Local: sea/land breeze, mountain wind, …

� Energy density ∝ air density x (wind speed)3

� Wind turbine: “wind flow” to “generator rotation”

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Variation of Wind Energy

� Seasonal prevailing wind

� Local/regional weather

� Height above ground/sea level

� Topology & surface roughness

Renewable Energy in Hong Kong

RE Application in HKResources

� Type available

� Solar, Wind?

� Others?

� Quality

� Power density:

solar radiation ~ 10 – 20 MJ/m2/day

wind (HK Observatory) ~ 485 W/m2

� stability, reliability, predictability

Solar Resources in HK

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MJ/m2

EMSD Report: A typical horizontally mounted flat PV system is expected to generate about 121 kWh/year per m2 of PV panel

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Wind Power Density in HK

Solar Water Heating System

Flat-plate solar

collector

Evacuated tube solar

collector

Heat transferred from absorber plate to flow tubes

Heat transferred from absorber coating in evacuated tube to U-circulating pipes

Comparison between the solar collectors

Flat-plate type Evacuated-tube type

Equipment cost

($/m² collector surface)1000 - 1500 2600 – 3000

Efficiency* (%) 30 - 40 40 - 45

Functional life 15 - 20 15 - 20

Note :

* Efficiency defined as system thermal energy output over the horizontal solar radiation

Example – A Service ApartmentFlat-plate Solar Collector

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Example – A local universityEvacuated Tube Solar Collector

Solar Thermal System (HKUST)Example – A local University

Evacuated Tube Solar Collector

Solar Thermal System (HKUST)Solar Photovoltaic (PV) Panels System

Mono-crystalline Poly-crystalline Amorphous silicon

Made from a single Made from a single Made from a single Made from a single continuous crystal lattice continuous crystal lattice continuous crystal lattice continuous crystal lattice structurestructurestructurestructure Silicon wafers are Silicon wafers are Silicon wafers are Silicon wafers are produced by casting and produced by casting and produced by casting and produced by casting and sawing or by forming sawing or by forming sawing or by forming sawing or by forming thin ribbons directly from thin ribbons directly from thin ribbons directly from thin ribbons directly from the silicon meltthe silicon meltthe silicon meltthe silicon melt Use a homogeneous Use a homogeneous Use a homogeneous Use a homogeneous layer of silicon rather layer of silicon rather layer of silicon rather layer of silicon rather than a crystal structurethan a crystal structurethan a crystal structurethan a crystal structureSolar Thermal System (HKUST)Solar Photovoltaic (PV) Panels System

Mono-crystalline Poly-crystalline Amorphous silicon

Cell efficiency (%) 15 – 18 13 – 16 5 – 8

Advantages Highest efficiency

• Cheaper than mono-crystalline cells;

•Simpler and less energy intensive to manufacture than mono-crystalline cells

•Cheaper than crystalline cells;

•Can use on curved and flexible surfaces;

•Light weight

Disadvantages

•Complicated and relatively expensive to manufacture;

•Heavy weight compared to thin-film installation

•Less efficient than mono-crystalline cells;

•Heavy weight compared to thin-film installation

Less efficient than crystalline cells

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Solar Thermal System (HKUST)Availability of solar insolation in Hong Kong

Orientation of modules Annual average global solar insolation

(kWh/m2 of panel area)

Fixed, tilted 17o towards south 1321

Horizontal 1296

Vertical, south wall 752

Vertical, east or west wall 711

Two-axis tracking, flat plate 1594

Some Local Application Examples

Solar PV SystemA Commercial Complex in Tsuen Wan

Solar BIPV System

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7.2kW Solar Flexible PV SystemKadoorie Farm & Botanic Garden

Wind Turbines

Pole-mounted long blade type Circular-type wind turbines

Features:

•Heavy-weight—impose structural

load;

•Start-up wind speed of at least 3

m/s

Features:

•Light-weight;

•Rated power can vary depending

on modules used;

•Start-up wind speed down to 2 m/s

Wind Speed Evaluation

Using wind resource map at http://wind.emsd.gov.hk/Wind_Resource_Mapping.html

Kowloon Tong!

Calculation result

RE Application in HKCapture & Conversion

� Technology� Solar water heater (SWH), Photovoltaic (PV)� Wind turbine

� Efficiency� Solar water heater: ~ 20 – 30%� PV: ~ 10 – 20%� Wind turbine: 60% max

� Price� PV: ~ US$5 – 7/W� Mini/small wind turbine: ~ US$ 2 – 3/W� SWH: ~ US$1100 – 1800/unit (120 – 160 litre)

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Considerations for On-grid or Off-grid RE System

Standalone (Off-grid)

An example of off-grid PV system• Operate independent of grid

supply• No approval required• Batteries required for

continuous power supply• Capacity limited by batteries• Batteries may become

harmful waste on disposal

Grid-connected (On-Grid)

An example of on-grid PV system

• No battery required• Higher efficiency—effective use of

electricity once generated• Relevant authorities’ approval

required

Requirements on grid-connected RE system

EMSD CLP HK Electric

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Requirements on grid-connected RE system

Four major requirements:1. Safety2. Equipment protection3. Supply reliability4. Power quality

• Warning Labels• Lockable Switch• Anti-islanding Test

• Power Factor• Harmonic Distortion• Earth-loop Impedance• Under Voltage Protection• DC Fault protection

• DC Diode• DC Fuse• DC Isolator• MCCB

• Surge Arrestor• RCCB

• Utility Check Meter Provision

• Inverter c/w built-in transformer or external transformer

Simplify Schematic for Small PV System

Grid-connection Point

Lockable Isolating Switch

MCB / RCCB Provision

Utility Check Meter Provision

DC/AC Inverter for Grid-connection Application

Max DC Voltage and Current

Starting Voltage

MPP Voltage Range

Build-in / External Transformer

Positive / Negative Grounding Kits

String Fuse Rating

PV Cable Size

Surge Arrestor

DC Isolator

Anti-Islanding Function

Power Factor

Harmonic Distortion

Earth-loop Impedance

Under Voltage Protection

DC Fault protection

DC Link Box

PV Panel Array

String Voltage

String Current

System Current

Earthing Provision

Design Standard: NEC 690

Case Study - Town Island

Town Island Location

Town Island (伙頭墳洲):Drug rehabilitation centre operated by Operation Dawn [香港晨曦會]

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Background

� Customer: Operation Dawn Ltd., a non-profitmaking organization adopting Christiantreatment & rehabilitation for drug addicts ofdifferent nationalities on the Island

� Currently, there are 3 concrete buildings of intakehostels, a church and 2 water pumps

Supplying Electricity to a Remote Island

� Off-grid RE system powered by Sunlight and Wind + Battery Bank asbackup.

� Collected solar radiation and wind data from Hong Kong Observatory forthe design of PV, wind turbine and battery capacity to meet the customer’sload profile.

� In daytime, PV + wind turbines power the load and charge the battery.

� Battery system stores the energy to supply the customer when there is littlesunlight and wind.

� Battery capacity can supply 2 days consumption or longer with proactiveload curtailment by the customer, without any recharging by PV or windturbine.

� Customer’s generator will be switched on when the RE system reservedenergy drops to 20% and cuts off its output.

System Design Consideration

� Off-grid system for remote area. Powered by RE (solar + wind + battery).

� Intermittent nature of RE resources and limit of battery capacity, therefore, outage is possible.

� Extend the system availability by load control and demand side management e.g. cut off some loads by the customer when the energy reserve becomes low

Site Photo

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Standalone PV System Sizing

1. Estimating the user daily average energy consumption (kWh) and Critical loads (kW)

2. Calculating the required PV peak power (kWp) and the PV inverter nominal power (kW)

3. Calculating the battery capacity (Ah) and the bi-directional battery inverter power (kW)

Max. Power Point (MPP) tracking of PV

1. Estimating the user daily average energy consumption (kWh) and Critical loads (kW)

2. Calculating the required PV peak power (kWp) and the PV inverter nominal power (kW)

3. Calculating the battery capacity (Ah) and the bi-directional battery inverter power (kW)

Max. Power Point (MPP) tracking of PV

� Stronger irradiation increases the magnitude of current whilst the voltage remainsvirtually the same.

� Higher temperature in contrast lowers the voltage whilst the strength of current remainsvirtually the same.

� Inverter has the task to maintain the solar modules at the MPP constantly

� Through the changing of its internal resistance.

� MPP tracking and changing the internal resistance at regular time intervals andobserving the resulting power changes

Load Estimation and PV Sizing

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Major Equipment – PV Panels

Technology Output Efficiency Application and Market Trend

Monocrystallinesilicon

~14% Market share 35%

(up to 180W per panel 1.5m x 1m)

Polycrystalline silicon

~12% Market share 50%

(up to 270W per panel 2m x 1m)

(Selected for Town Island Project,

better cost/W/sq. m)

Thin Film ~8% Building integrated (BIPV)

(Half of output of crystalline panel)

Major Equipment – Wind Turbine 6kW

Major Equipment – Wind Turbine 6kW

PV System Installation Hits

� Shadow effect

� Site Orientation

� Buildings Department Submission

� Wind Load

� Roof Top Water Proof issues

� 3-Phase Balance

� Grid-connection Submission

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Maintenance

• Data Analysis- Power, Voltage, Current, Frequency

• Visual Inspection- Physical damages, dirt- Discoloration, Burnt Marks

• Site Measurement- Voltage across diodes, fuse- String Current- Thermal imaging- Power quality measure for overall system

Renewable Energy Application in Worldwide

Solar Thermal (1)Water Heater & Cooker

NREL, USA

Solar Thermal (2)Furnace & Power Generation

Gerhard Weinrebe

NREL, USA

Schlaich Bergermann & Partner

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Solar Thermal (3)Solar Chimney

Schlaich Bergermann & Partner

NREL, USA

Solar Thermal (4)Solar Pond

University of Texas

Photovoltaic (1)

NREL, USA

Photovoltaic (2)

NREL, USA

NREL, USA

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Photovoltaic (3)

NREL, USA

NASA & NREL, USA

Photovoltaic (4)

NREL, USA

7.4MWp, Gottelborn, German 4.6MWp, Springerville, USA

5MWp, Leipzig, German

4MWp, Saarland, German

Daylighting

NREL, USA

NREL, ORNL, Oikos

Wind Power (1)Windmill

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Wind Power (2)Small wind turbine

Wind Power (3)Commercial Wind Turbine

Wind Power (4)Alternative wind turbine

HydropowerWater Wheel & Small Hydro

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Biomass

NREL, USA

Geothermal

NREL, USAs

Ocean

Rance, FranceOcean Power

Delivery

Thank You