Renewable EnergyPhotovoltaic - Solar Cell

Daniel Pham

Solar SourceSolar Source

• The average solar power incident on Continental US is 1600 x 1012 W

This is 500x the power consumption in US (3.3 x 1012 W)

• If we cover 2% of the continental US with 10% efficient PV systems, we would make all the energy we need.

• FYI:• 1.5% of Continental US is covered by roads

Drivers for Solar powerDrivers for Solar power

• 2 billions people without electricity worldwide• Low cost for remote requirements

• Power line extension costs $10,000 to $30,000 per mile

• Reduce peaking loads• Government subsidies • Environmental friendly

How Photovoltaic Solar Cell WorkHow Photovoltaic Solar Cell Work

p-n junction

Light can be separated into different wavelengths Only photon has more energy required can generate electron-hole pair

High band gap PV cell provides higher voltageTypical efficiency of commercial PV is around 12%

Theoretical Efficiency of Photovoltaic Cell

Types of Photovoltaic CellTypes of Photovoltaic Cell First Generation PV Cell: First Generation PV Cell:

– Single crystalline siliconSingle crystalline silicon– Multi-junction cell (different band-gap materials)Multi-junction cell (different band-gap materials)

Second Generation PV Cell:Second Generation PV Cell:– Thin film silicon (amorphous silicon)Thin film silicon (amorphous silicon)– CdTe (Cadmium Telluride)CdTe (Cadmium Telluride)– CuInSeCuInSe2 2 (Copper Indium Diselenide)(Copper Indium Diselenide)

Third Generation PV CellThird Generation PV Cell– Ultra-High Efficiency concepts (>80%)Ultra-High Efficiency concepts (>80%)– Ultra-low Cost Ultra-low Cost

Polymer cells with quantum dots or nanostructuresPolymer cells with quantum dots or nanostructures

CdTe rods in polymer Carbon nanotube on Sifor more efficient solar power

Photovoltaic RoadmapPhotovoltaic Roadmap

1st Generation PV Crystalline Silicon

2nd Generation PV Thin Film

3rd Generation PV Ultra-High Efficiency

Ultra-Low Cost

Source: European Commission meeting Dec. 2004

Decline Price of PVDecline Price of PV

Where is the cost:

• Produce wafer (40%)• Fabricate cell (30%)• Interconnect and laminate (30%)

PV manufacturing cost

• Installation cost (same as cost of the module)

State, federal, utility and other subsidize combine paying half of the cost

Worldwide PV GrowthWorldwide PV Growth

Source: European Commission meeting Dec. 2004

Future Reality ?Future Reality ?

Within 50 years, photovoltaic will supply more than half of the world’s

supply energy

If the PV market growth continues at rate of 20% and panel lasts 50yrs, there will be 100 TW

of energy provide by PV cells on the ground

Government Policy For Solar EnergyGovernment Policy For Solar Energy National Energy Policy Act of 1992 National Energy Policy Act of 1992

– Using other alternative energy sources by 2010Using other alternative energy sources by 2010– Reduce green house gas emission by other alternative energy sourcesReduce green house gas emission by other alternative energy sources

Alternative Fuels Initiative (Summer 1998)Alternative Fuels Initiative (Summer 1998)– Energy Smart Schools, to cut energy bills in schools and reinvest the savings in Energy Smart Schools, to cut energy bills in schools and reinvest the savings in

educating the nation's most valuable resource - our children. (Solar power panel educating the nation's most valuable resource - our children. (Solar power panel started installing in schools)started installing in schools)

The Million Solar Roofs Initiative, announced in June, The Million Solar Roofs Initiative, announced in June, 1997, by President Clinton, 1997, by President Clinton, to install solar energy systems on one to install solar energy systems on one million rooftops by the year 2010. million rooftops by the year 2010.

The Energy Policy Act of 2005, the new national energy law signed by The Energy Policy Act of 2005, the new national energy law signed by President Bush on August 8, 2005, valuable federal tax creditsPresident Bush on August 8, 2005, valuable federal tax credits

Financial OpportunityFinancial Opportunity– Federal, State and subsidize for consumer Federal, State and subsidize for consumer – Grants, Federal funding for manufacturing and developmentGrants, Federal funding for manufacturing and development

ConclusionsConclusions Solar power source is abundant Solar power source is abundant Many types of PV cells are in development Many types of PV cells are in development

to meet to PV Roadmap for future needsto meet to PV Roadmap for future needs PV cells’ efficiency can be increased and PV cells’ efficiency can be increased and

underdevelopmentunderdevelopment Solar power from PV cell are safe and Solar power from PV cell are safe and

potentially growing potentially growing