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Current Status of Solar Energy in Taiwan and Its Prospect 2013.6.8. 蕭國瑞博士 Kuo-Jui Hsiao Ph.D. Assistant Professor Institute of Electro-Optical Science and Technology National Taiwan Normal University, Taipei 11677, Taiwan Email: kjhsiao@ntnu.edu.tw. Electricity Use.
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Current Status of Solar Energy in Taiwan and Its Prospect 2013.6.8 蕭國瑞博士Kuo-Jui Hsiao Ph.D. Assistant Professor Institute of Electro-Optical Science and Technology National Taiwan Normal University, Taipei 11677, Taiwan Email: kjhsiao@ntnu.edu.tw
Electricity Use • Electricity use increases with human development. Benka S,Physics Today38, 39 (2002); adapted from Pasternak A, Lawrence Livermore Natl. Lab report UCRL-ID-140773(October 2000).
Why Renewable Energy • Energy: heat, electricity, light, kinetic energy, potential energy, etc. • Renewable energy: energy which comes from natural resources and can be naturally replenished. • Type: sunlight, wind, tides, waves and geothermal heat. • Environmentally, renewable energy is a good energy source. • fossil feul: gas → CO2 → green house • nuclear energy: waste, irreversible damage figure from zmescience.com
Why Solar Energy • Photovoltaics: A method to generate electrical power by converting solar radiation to direct-current electricity. • Solar cell: A device to convert solar radiation to direct-current electricity. • Advantage: • Environmentally-benign • Infinite • Solar energy / power comsumption ~ 10000 • The sun will shine for the next 6 x 109 years. • Accessible: satellite, lighthouse • Income • Operator free • Solar module target: • high efficiency, low cost, good reliability • A laptop power supply ~ 65 W • ~(0.9 sun) x (60 cm x 120 cm) x (Eff = 10%)
Solar Modules • Inorganic: • Si-based: polycrystalline Si amorphous Si monocrystalline Si • Compound: CdTe, CIGS, CZTS, etc. • Quantum dot • Oganic: dye-sensitized solar cell (DSSC), polymer thinfilm, hybrid figure from several PV companies
Sun and Sunlight • The Sunis a sphere of gas with a temperature of 6000 K on the surface. • Air mass (AM) = 1/cos θ, θ: angle to overhead, AM0: in the space ~ 1.35 kW/m2. • STC: AM1.5, θ ~ 48 °, power density ~ 1 kW/m2. • Attenuation through the atmosphere: 1. Rayleigh scattering ~ 1/ λ4, • 2. scattering by particles, 3. absorption. • Diffuse sunlight (indirect): blue rich • Solar simulator is classified by spectral mismatch, uniformity, and stability. θ figure from “Solar Cells” by Martin Green
Theoretical analysis of the optimum bandgap for solar-cell application • 1.4-eV bandgap is good for solar-cell application at different latitudes. Maximum efficiency of single junction solar cell versus absorber energy band gap of the calculated for solar spectra corresponding to various Air Mass factors. T. Zdanowicz, T. Rodziewicz, M. Zabkowska-Waclawek, Volume 87, Issues 1–4, May 2005, Pages 757–769
Solar Power in Taiwan • Example: • In Taichung, 3.5 kWh/kWp/day. • A 12% module (120W/1m2 )can generate 0.42 kWh/m2/day. • For a system in Taichung: • A 1-kWp solar system, including 8 modules and 3-ping space, can generate 1226 kWh/year. • < 24528 kWh for a 20-year lifetime, and cost ~ 75 kNTD + 3-ping land cost. • Current status: • For an investor, interest < 4.2%/year – 8.7%/year, excluding land cost. • For government, cost/watt (> 3.06 NTD/kWh) is high, excluding land cost. • 台灣經濟部公告 • 太陽光電發電設備電能躉購費率: 財團法人中華民國核能協會 我國主要發電方式內部成本
Cost/Watt for a System • Cells → Modules → System: Current match and voltage match • Cost/watt for a system depends on: • Module properties • Module efficiency • Cost for a module • Reliability • Environment • Solar radiation • Temperature • Low light • Other cost • Balance of System (BOS), including land, inverter, engineering, construction, etc. • Maintenance
Best Research-Cell Efficiency 28.8 Rev. 03-2013
Best Module Efficiency • Efficiency loss: • Uniformity: current and voltage mismatch • More resistance • Encapsulation • Aperture area to module area 16.1 From Prog. Photovolt: Res. Appl.2013;21:1–11, Received 14 November 2012
Efficiency/Bankability-Adjusted Supply Stack 2013 http://www.greentechmedia.com/channel/solar
Module Data Sheet Datasheet of First Solar module
Module Data Sheet Datasheet of First Solar module
Certification for Reliability and Safety • Certification standards are designed for pre-screen. • eg. The testing sequence prescribed in IEC 61646 failure rate 3 1 2 • Infant mortality • Working life • Wearout time
Cost/Wp for a System • Cost/Wp for a system depends on: • Module properties • Module efficiency: 10% - 22% • Cost for a module: > 0.68 USD/Wp, price ~ 0.8 USD/Wp • Reliability: 90% for 10 years and 80% for 25 year • Environment • Solar radiation: 2 – 5 kWh/kWp/day • Temperature: 25 – 60 ∘C ~ -10% • Low light: 0 ~ - 10% • Other cost • Balance of System (BOS), including land, inverter, engineering, construction, etc. • Maintenance: remote monitor
Ideal Solar Power in Taiwan • Assumption: • In southern Taiwan , 5 kWh/kWp/day. • A 1-kWp solar system on 2-ping space, can generate 1825 kWh/year. • < 42888 kWh with warranty of 0.9 for 10 year and 0.8 for 25 year, and cost ~ 54 kNTD + 2-ping land cost. • Ideal solar power in Taiwan • For government, cost/watt will be reduced from “> 3.06 NTD/kWh +land cost” to “> 1.28 NTD/kWh + 2/3 land cost”. • The cost of solar energy in Taiwan could be very competitive to other energy sources with the best we can have today or in the near future. without green tax 財團法人中華民國核能協會 我國主要發電方式內部成本 1.28 NTD/kWh
Solar Energy v.s. Nuclear Energy 表中汙染代價與社會觀感未被考慮。 • Solar energy is hard to be the major energy source due to its short uptime and small power-generation density.
Summary • Environmentally and economically, solar energy is a good energy source. • The cost of solar energy in Taiwan could be very competitive to other energy sources with the best we can have today or in the near future. • Solar energy is hard to be the major energy source due to its short uptime and small power-generation density. • Cost/Wp depends on: • module properties (0.68-1USD/Wp, 80% for 25 years, -0.25%/K, LIP = 90%, material) • solar radiation (2 – 5 kWh/kWp) • BOS • maintenance
Thomas Edison Quotes “I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait until oil and coal run out before we tackle that. I wish I had more years left.”