SOLAR CELLS

ESW Sustainable Technology of the Month!

Presented by: Brad Gething

DISCLAIMER

I am not an expert in photovoltaics  This presentation is not a comprehensive review of the state of the art.

Not all of the information presented originates from peer reviewed sources.

BACKGROUND

1839 -

Photovoltaic effect was discovered by the French physicist Alexandre Edmond Becquerel.

1918 -

Polish scientist Jan Czochralski discovered a method for monocrystalline silicon production. The first silicon monocrystalline solar cell was constructed in

1941

.

1955 -

W. Western Electric put for sale commercial licenses for solar cells production (mainly for space exploration). Hoffman Electronics Semiconductor Division introduced a commercial photovoltaic product with 2 % efficiency for $25 per cell with 14 mW peak power. Cost - $1,785 per

1973 –

U. Delaware produced a photovoltaic-thermal hybrid system Solar one, one of the first photovoltaic systems for domestic application. Cost $30 per W

1984 -

1 MW photovoltaic power plant began to operate in Sacramento, California. ARCO Solar introduced the first amorphous modules.

1992 -

A silicon solar cell with 20 % efficiency was patented.

2002 -

MW Cumulative worldwide installed PV capacity expected to reach 2000

World Energy Demand GW-hr

2003

1.233

E 8

2030 (est.)

2.116

E 8 US Energy Demand GW-hr

2003

2.937

E 7

2030 (est.)

3.844

E 7

CONTEXT

AVERAGE SOLAR IRRADIANCE 1991-1993 W/m 2

Location, Desert

Africa, Sahara

CONTEXT

Desert Size km 2 Irradiation W/m 2 Area Required km 2

9,064,960 260 144,231 265 141,509 Australia, Great Sandy China, Takla Makan Middle-East, Arabian South America, Atacama U.S.A., Great Basin 388,500 271,950 2,589,910 139,860 492,100 210 270 275 220 178,571 138,889 136,364 170,455

Energy Output GW-hr

2.055

E 7

HOW THEY WORK

Si-P Si-B 1 Si-P 3 Si-B Si-P 2 Si-B

ECONOMICS

A 3 kW PV residential retrofit system in the US costs ~$25,000 Amortized over a 20 year mortgage, the cost of PV electricity is ~25 cents per kWh in most U.S. locations The average cost of utility/grid electricity is 8.2 cents per kWh in the U.S. and between 0.10 and 0.15 €per kWh in Europe.

Studies suggest an added hidden societal cost behind all fossil-fueled power plant ranging from 7 to 20 cents per kWh.

ECONOMICS

Although the production of electrical grade Si has increased, acquisition of raw Si has not.

DEMAND > SUPPLY

ECONOMICS

KEY POINT

Costs can be reduced by:  Alternative materials Reduced material cost Reduced processing cost Increased efficiencies  Alternative uses of Si Amorphous Si (non-crystalline) Si layered with glass

ALTERNATIVES

Materials

  

Cadmium Telluride Polymers Dye-sensitized solar cells Processing

  

Thin films Ribbon Printing Nano-crystalline materials

EFFICIENCIES

Amorphous silicon (Tandem) Cadmium Telluride (CdTe) thin film Multi (or Poly) crystalline silicon Mono-crystalline silicon (SiN) Saturn Mono-crystalline silicon 6 - 7% 8 - 10% 12 -15% 13 -16% 15 -18%

WANT TO LEARN MORE?

PSU Courses   EDSGN 497A: Sustainable Design and Engineering ENGR 097S: Solar Racers Center for Sustainability (www.engr.psu.edu/cfs)   Solar Decathlon www.solar.psu.edu

Powerlion- portable PV station  New 1750 W PV array Penn State Energy Institute – Sustainable Energy Research Faculty   Dr. Andy Lau – ASE Dr. Christopher Wronski – EE  Dr. John Asbury - Chemistry

REFERENCES

http://www.pvresources.com/en/history.php

http://en.wikipedia.org/wiki/Photovoltaics http://science.howstuffworks.com/solar-cell.htm

“Everything You Wanted to Know About Solar PhotovoltaicsBut Were Afraid to Ask”, BP Solar Publication International Energy Outlook 2006,

Energy Information Administration Annual Energy Outlook 2007

,

Energy Information Administration

Flin, David. “Thin films for fat profits”,

Modern Power Systems

, 26(2), 2006.

“I'd put my money on the sun and

solar

energy. What a source of power! I hope we don't have to wait till oil and coal run out before we tackle that.”

--Thomas Edison

LET’S CHAT!

QUESTIONS??

COMMENTS??

“If to do were as easy as to know what is good to do, then paupers would be princes and a poor man’s hovel, a rich man’s estate.” –

William Shakespeare