Solar Voltaic Energy. Associate Professor Mazen Abualtayef. Environmental Engineering Department. Islamic University of Gaza, Palestine

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1 Solar Voltaic Energy Associate Professor Mazen Abualtayef Environmental Engineering Department Islamic University of Gaza, Palestine

2 Adapted from a presentation by Professor S.R. Lawrence Leeds School of Business, Environmental Studies University of Colorado, Boulder, CO, USA

3 Outline Overview of Solar Power How Photo-voltaic (PV) Cells Work How Solar PV Cells are Made Solar PV Applications Efficiencies Economics Facts & Trends Research

4 Solar Power Overview Video Photo means light Voltaic means electricity Photovoltaic means getting electricity from light

5 The Sun provides 1,400 watts/m² at the distance of the Earth's orbit, but less at ground level

6 PV Solar Radiation

7 PV Solar Radiation Palestine Solar Radiation Map Gaza: >1900 kwh/m 2 /year

8 Photon Energy A photon is an elementary particle, the quantum of light and all other forms of electromagnetic radiation Visible light has a wavelength in the range of about 380 nanometres to about 740 nm

9 Light & the Photovoltaic Effect Certain semiconductor materials absorb certain wavelengths The shorter the wavelength the greater the energy Ultraviolet light has more energy than infrared light Crystalline silicon Utilizes all the visible spectrum plus some infrared radiation Heat vs. electrical energy Light frequencies, which is too high or too low for the semiconductor to absorb, turn into heat energy instead of electrical energy

10 How PV Cells Work

11 Florida Solar Energy Center

12 What are PV Cells? Si Si Si Si Si Si Si Si P Si Si n-type Si Si B Si Si p-type

13 Cross Section of PV Cell Video

14 How Solar Cells are Made Video

15 Solar Cell Construction Materials Crystalline Silicon الغاليوم زرنيخيد expensive) Gallium Arsenide (more Grown into large single-crystal ingots Sawed into thin wafers 2 wafers are bonded together (p-n junction) Wafers grouped into panels or arrays

16 Creating Silicon Wafers فحم الكوك فرن قوس التقطير بوليكريستال السيليكون رقائق السيليكون التلميع كريستال السيليكون

Growing Silicon Ingots http://en.wikipedia.

17 Growing Silicon Ingots سبائك السيليكون سيليكون منصهر قطع السيليكون Czochralski Process The Czochralski process is a method of crystal growth used to obtain single crystals of semiconductors (e.g. silicon, germanium and gallium arsenide), metals (e.g. palladium, platinum, silver, gold) and salts.

18 Drawing a Silicon Ingot

19 Silicon Ingots & Wafers Special high-speed saws slice the ingots into wafers about the thickness of a dime

20 Creating PV Cells

Computer Chips on Wafer http://d0server1.

21 Computer Chips on Wafer

22 Silicon Solar Cell

23 Florida Solar Energy Center PV Cells have efficiencies approaching 21.6%

24 Solar Modules and Arrays

Solar PV Systems Cells are the building block of PV systems Typically generate 1.

25 Solar PV Systems Cells are the building block of PV systems Typically generate watts of power Modules or panels are made up of multiple cells Arrays are made up of multiple modules A typical array costs about $1.2 $1.5/watt (Chinese) Still need lots of other components to make this work Typical systems cost about $5-$6/watt

26 Florida Solar Energy Center

27 Florida Solar Energy Center PV Modules have efficiencies approaching 17% الصفيحة Laminate:

28 Solar Panel Solar panel by BP Solar at a German autobahn bridge

29 Florida Solar Energy Center

30 Florida Solar Energy Center

31 Florida Solar Energy Center

32 Florida Solar Energy Center الفناء Patio:

33 Solar PV Applications

34 Spacecraft International Space Station Hubble Telescope Mars Rover

Recreational Use (Sailboat) In 1999-2000 two people sailed Rusalka Mist from the island of Jersey in the English Channel, via Tenerife to the Caribbean and back via

35 Recreational Use (Sailboat) In two people sailed Rusalka Mist from the island of Jersey in the English Channel, via Tenerife to the Caribbean and back via the Azores. The solar panels and a towed, water-power generator provided selfsufficiency in electrical energy during this trip, both at sea and at anchor during the year.

36 Remote Areas (Mexico) A solar panel in Marla, Cirque de Mafate, Réunion

37 Residential

38 Commercial Solar Centre at Baglan Energy Park in South Wales

39 Solar PV Efficiency

40 Efficiencies

41 Solar Cell Efficiencies Typical module efficiencies ~12% Efficiency range is 6-30% 6% for amorphous silicon-based PV cells 20% for best commercial cells 30% for multi-junction research cells Typical power of 120 W/m 2 Mar/Sep equinox in full sun at equator تساوي الليل والنهار Equinox:

42 Solar Panel Efficiency ~1 kw/m 2 reaches the ground (sunny day) ~20% efficiency 200W/m 2 electricity Daylight & weather in northern latitudes 100 W/m 2 in winter; 250 W/m 2 in summer Or 20 to 50 W/m 2 from solar cell Value of electricity generated at $0.1/kWh 1 km 2 would generate up to 50 MW Sahara desert is over 9 million km MW/km 2, or TW (Global power rate is 15 TW)

43 Solar PV Facts & Trends

44 World Solar Power Production

45 World Solar Power Production

46 Solar PV Components Inverter Converts DC power from solar array to AC for use in your home Wiring Connects the system components Batteries Used to store solarproduced electricity for nighttime or emergency use Mainly used for remote sites that aren t tied into the electrical grid Charge controller Prevents batteries from being over charged Disconnect switches Allows power from a PV system to be turned off Electrical meter Measures electrical production and use Often runs backward if system is attached to the electrical grid Total system cost = $3.00~$4.00 / watt

47 Stand Alone Solar PV System BATTERY

48 Grid Connected Solar PV System

49 Connecting PV to the Grid

50 Net Metering When your system produces more electricity than your home uses electricity flows backward out to the grid Meter runs backward and you get credit for the electricity you sell to the utility

51 Florida Solar Energy Center

52 Florida Solar Energy Center

53 Siting & Designing Solar PV

54 Solar PV Dependencies Location, Location, Location! خط عرض Latitude Lower latitudes better than higher latitudes Weather Clear sunny skies better than cloudy skies Temperature not important Direction solar arrays face South preferred, east and west acceptable Absence of shade Trees, Flatirons, etc.

55 Solar PV Design Key Factors Location How much solar radiation does the system receive? DC rating How big is the system

56 Solar PV Design Module Module Efficiency How efficiently does the solar system convert solar radiation into DC power Best retail systems approaching 17% DC to AC derate factor How efficient is the system converting DC to AC power

57 Solar PV Array Design Array Flat Panel Remains in a constant fixed position Array tilt (equal to latitude best) Increase solar radiation by 10-20% compared to 0% tilt Sunnier locations benefit more زاوية السمت best) Array azimuth (180 Directly south

58 Solar PV Array Tracking Array 1-axis tracking Tracks sun across the sky during each day Stays at a constant tilt Increase solar radiation by 25-30% compared to no tracking Sunnier locations benefit more Array 2-axis tracking Tracks sun across the sky during each day Adjusts tilt more in winter, less in summer Increase solar radiation by 33-38% Sunnier locations benefit more

63 Off grid solar system design 1. Load Calculation Room Load Quantity Working hours [hrs] Energy [Wh] Guest room 25W PL Living room 25W PL Master bedroom 25W PL Boys bedroom 25W PL Girls bedroom 25W PL Balcony 25W PL Bathroom 25W PL Corridors 25W PL Kitchen 25W PL Fridge Total Energy [Wh/day] 3500

64 Off grid solar system design 2. Solar System Sizing: PV sizing = Load / sunny hours / derate factor = 3500 / 5 / 0.70 = 1000 Wp System is used 250W / 24V panels 1 kw PV array (1000 DC watts) 1000/250 (watts per panel) = 4 panels 4 series strings of 1 panels = 4 modules with each string producing 24 volts

65 Off grid solar system design 3. Battery Bank Sizing: System is used GEL battery 12V/100 Ah C10 kwatts of PV array required = kwh / daily sun hours / derate factor 1 kwp = kwh / 5 / 0.7 kwh = 1k * 5 * 0.7 = 3.5 kwh

66 Off grid solar system design 3. Battery Bank Sizing: Battery Bank Capacity = kwh per day * Day of Autonomy / (losses * DOD * 24 (system voltage)) Battery Bank Capacity (1 day) = 3.5k * 1 / (0.85 * 50% * 24) = 343 Ah No. of Batteries 1 set to get 24V = 24/12 = 2 with 100Ah C10 No. of Batteries to get 686 Ah = (343/100) * 2 = 6

67 Off grid solar system design 4. Charge controller sizing: System is used MPPT Solar controller charger VT W / 24V = 40 A No. of MPPT = 1 5. Inverter Sizing: AC system watts = DC watt x derate factor = AC system watts= 1 kwp * 0.7 = 0.7 kw No. of inverter = 1 =1 kva

68 Off grid solar system design 6. Economics: Cost of PV system = US$ 3500 Annual electricity cost = 1456*0.125 = $182 Payback period = = 19 yrs Cost of Energy = ($3500)/(1456*25) = US$0.10 / kwh

69 PV Calculator A solar photovoltaic calculator was developed by Mazen Abualtayef and you can find it at

70 Solar PV Economics

71 Solar PV Energy Payback Expected lifetime of 40 years Payback of 1-30 years For 1.0 kw 2-Axis Tracking panels the Payback = $3,500 / (1,962 kwh/year $0.125) = 14 years For 1.0 kw fixed tilt panels the Payback = $3,500 / (1,456 kwh/year $0.125) = 19 years

72 Cost Analysis Module price = ~$ / W Installations costs = ~$0.50 / W Cost for a 1 kw system = ~US$3,500-4,000 Typical payback period is 25~30 years

73 Economic Example 1/ watt system $4,000 initial cost 1000 watt (1 kw) system is about 7.25 m 2 Assume 5.40 kwh/m 2 /day for fixed tilt Or 7.00 kwh/m 2 /day for 2-axis tracking 7.25 x 5.40 = DC kwh/day (solar radiation) hitting the solar modules Cost from

74 Economic Example 2/3 Module Efficiency = 15% kwh/day x 0.15 = 5.87 DC kwh/day Derate factor 76% Takes into account inefficiencies in the DC/AC conversion and internal module components 5.87 DC kwh/day x 0.76 = 4.46 AC kwh/day Output = 4.46 kwh/day 1640 kwh/year (fixed tilt) 5.65 kwh/day 2060 kwh/year (Tracking)

75 Economic Example 3/3 Pay $4,000, save $205/year 1640kWh/year x $0.125/kWh for fixed tilt Cost of Energy = ($4000)/(1640*25) = $0.10/kWh Compared to $0.125/kWh from PEC

76 Solar PV Cell Research

77 Emerging PV Techologies Cells made from gallium arsenide 35% efficiencies have been achieved Non-silicon panels using carbon nanotubes Quantum dots embedded in special plastics May achieve 30% efficiencies in time Polymer (organic plastics) solar cells Suffer rapid degradation to date

78 Thin Film Solar Cells Use less than 1% of silicon required for wafers Silicon vapor deposited on a glass slice Amorphous crystalline structure Many small crystals vs. one large crystal it is more efficient to absorb the visible part of the solar spectrum, but it fails to collect the infrared

79 Florida Solar Energy Center

80 Flexible PV Cells Gerrit Kroesen, Eindhoven University of Technology, the Netherlands

82 Benefits/Costs of Solar PV Reduces pollution Stabilizes electricity costs Lessens dependence on fossil fuels Increases self-reliance Can size for small, on-site installations Not grid dependent يقلل Lessens

83 Solar Thermal Energy

84 Solar Thermal Collectors Focus the sun to create heat: Concentrating Solar Power, CSP: Boil water Heat liquid Use heated fluid to turn a turbine Generate electricity

85 How does solar power station work?

Types of CSP: Parabolic Trough Capacity Range: 10-200MW. Thermal Cycle Efficiency: 30 40%, Land Use: 60 80 MW/km 2.

86 Types of CSP: Parabolic Trough Capacity Range: MW. Thermal Cycle Efficiency: 30 40%, Land Use: MW/km 2. Operating Temperature: 390 C; LEC ~$0.13 kwh. Thermal storage with oversized solar field allow plant to dispatch power during nonsolar times of day increase annual capacity factor ~ 50%.

90 Types of CSP: Linear Fresnel Reflector 177 MW Compact Linear Fresnel Reflector (LFR) proposed in California. LFR uses about MWe per km 2 of land. Current LEC $0.08~$0.10/kWh, operating temperature 265 C.

91 Linear Fresnel Reflector, AREVA North America us.arevablog.com

Types of CSP: Parabolic Dishes New solar-to-grid system conversion efficiency record of 31.25% set in Feb 2008. Capacity Range: 0.01-0.

92 Types of CSP: Parabolic Dishes New solar-to-grid system conversion efficiency record of 31.25% set in Feb Capacity Range: MW, Thermal Cycle Efficiency: 30~40%, Land Use: 80~120 MW/km 2 ; Engine Operating Temperature: 700 C; LEC ~$0.30/kWh

Types of CSP: Solar Towers Commercial 20 MWe PS-20 plant constructed in Spain. Capacity Range: 10-150 MW.

94 Types of CSP: Solar Towers Commercial 20 MWe PS-20 plant constructed in Spain. Capacity Range: MW. Thermal Cycle Efficiency: 30 40%, Land Use: MW/km 2 ; Operating Temperature: 567 C; LEC ~$0.30/kWh Efficient commercial-scale power towers are >>30 MW. Power Towers with molten salt thermal storage are expected to have annual capacity factor > 65% and LEC $0.07/kWh.

95 Solar Power Towers ps20 is the world first power tower plant, Spain

96 Examples of Solar Power Towers

100

101 CSP vs. PV Panels What is? CSP Mirrors are used to concentrate sunlight onto receivers that convert the solar energy to heat. Steam is created from that heat and goes through a turbine to generate electricity. PV A photovoltaic solar panel converts solar radiation into direct current electricity.

102 CSP vs. PV Panels Efficiency Differences CSP CSP efficiency increases with temperature (good for hot sunny places). Power Tower has reached a peak efficiency of 77%. The mean annual thermal collection efficiency for Solar Tres (Spain) is 41%. CSP is relatively new and improvement is still needed. PV Efficiency decreases with temperature (good for cold sunny places). At 0 c, maximum efficiency is 24-28% (depending what type of metal used. At room temperature, efficiency (for silicon) is 12%. Efficiency has been increasing over time.

103 CSP vs. PV Panels Efficiency Differences CSP Heat can be stored as thermal energy and converted to usable energy later. Can provide 24 hour/day electricity using energy storage. Uses a lot of water. PV Energy can be stored in batteries (not a sufficient amount). No energy produced without sunlight.

104 CSP vs. PV Panels Economic Considerations CSP Currently, it takes longer and is more expensive to build CSP plants... Cost estimates vary, but CSP is still not perfected. The price of CSP power production is expected to drop significantly in the next five years. PV which leaves photovoltaic as the leader in solar power. Photovoltaic has the advantage of being the more developed technology right now. Government subsidies for photovoltaic panels make it the current cheaper option.

105 CSP vs. PV Panels Economic Considerations CSP Current CSP projects are running around cents per kwh. PV A photovoltaic power plant would cost around 17 cents per kw. Technology for CSP is improving. It is still cheaper to use photovoltaic panels because their production time is lower and they cost less.

106 CSP vs. PV Panels Summary and Conclusion There are pros and cons to photovoltaic and concentrated solar power. Photovoltaic is cheaper to build and use, but CSP is newer and rapidly improving. CSP can store power for several hours and has an extremely high thermal efficiency.

107 CSP vs. PV Panels Summary and Conclusion Photovoltaic is the best choice for now. Research is still being done to continually improve efficiency. CSP is improving more rapidly and they will probably be equal competitors in the future. Location will play a large factor in the future of these two technologies. Photovoltaic and CSP technology may be combined for maximum efficiency in the future.

108 Next : Hydropower Power

ME 416/516 SOLAR ENERGY

ME 416/516 SOLAR ENERGY SOLAR ENERGY Introduction With the exception of nuclear power, all of the energy we use is solar in origin- wind and hydro are driven by solar heating. wood and other bio-fuels are solar energy converted