蕭國瑞博士 Kuo-Jui Hsiao Ph.D.Assistant Professor

Institute of Electro-Optical Science and TechnologyNational Taiwan Normal University, Taipei 11677, Taiwan

Email: kjhsiao@ntnu.edu.tw

Current Status of Solar Energyin Taiwan and Its Prospect

2013.6.8

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

monocrystalline Si polycrystalline Si amorphous Si

•Inorganic: •Si-based:

•Compound: CdTe, CIGS, CZTS, etc.

•Oganic: dye-sensitized solar cell (DSSC), polymer thin film, hybrid

figure from several PV companies

•Quantum dot

Sun and Sunlight

figure from “Solar Cells” by Martin Green

•The Sun is 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

Theoretical analysis of the optimum bandgap for solar-cell application

T. Zdanowicz, T. Rodziewicz, M. Zabkowska-Waclawek, Volume 87, Issues 1–4, May 2005, Pages 757–769

Maximum efficiency of single junction solar cell versus absorber energy band gap of the calculated for solar spectra corresponding to various Air Mass factors.

• 1.4-eV bandgap is good for solar-cell application at different latitudes.

Solar Radiation in Taiwan

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

Rev. 03-2013

28.8

Best Module Efficiency

From Prog. Photovolt: Res. Appl.2013;21:1–11, Received 14 November 2012

16.1

Efficiency loss:• Uniformity: current and voltage mismatch• More resistance• Encapsulation• Aperture area to module area

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

time

failure rate

12

3

1. Infant mortality2. Working life3. Wearout

•Certification standards are designed for pre-screen.•eg. The testing sequence prescribed in IEC 61646

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.

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

without green tax

Solar Energy v.s. Nuclear Energy

　 第四核能發電廠 中華太陽能公司 中華太陽能公司 火力發電廠

能源形式 核能 太陽能 ( 再生能源 )

太陽能 ( 再生能源 ) -

地點 新北市 恆春 (13676 公頃 )

嘉義縣 (190400 公頃 )

-

年發電量 ( 度 ) 21.3 G 21.3 G 21.3 G -

額定發電量 (GW) 2.7 11.7 14.6 2.7

興建費用 ( 億台幣 )

2800 5832 7290 1053

場地面積 ( 公頃 ) 480 7716 9645 -

運作風險 核災 無 無 -

使用年限 ( 年 ) 40 > 25 > 25 -

定位 主要能源 替代性能源 替代性能源 -

•Solar energy is hard to be the major energy source due to its short uptime and small power-generation density.

表中汙染代價與社會觀感未被考慮。

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 (0.68-1 USD/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.”

Thank you for your attention.