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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