1. SOLAR PV The conversion of solar energy directly into electricity in a solid state device

2. How does it work? Stream of photons hit panels at a suitable wave length Hits P-N junction and transfers energy to some electrons creating higher energy level Produces voltage of 0.5 V and delivers current proportional to sunlight intensity with a max of 3A

3. Materials Used Most made out of crystalline silicon –Monocrystalline- until recently always used, expensive –Polycrystalline- easier and cheaper than mono, but less efficient Others include: CIS- copper Indium diselenide CIGS- copper gallium diselenide CdTe- Cadmium telluride ( highest lab efficiency at 17%)

4. Different Technologies Thin Film- much cheaper but much less efficient (12%) than crystalline silicon Multi junction- 2+ PV junctions stacked together Concentrating systems- using mirrors and lenses to concentrate solar radiation Silicon spheres- tiny polycrystalline spheres, cheap & low grade Photoelectrochemical cells- not PV b/c its liquids- manufactured on small scale

5. Remote vs Grid Connected Remote –Runs with a battery for storage –Good for developing countries  fridges, water, pumping, lights Grid Connected –Transforms DC power from PV to AC at a voltage frequency that can be accepted by grid –Debt/ credit meters measure amounts bought and sold to utility

7. More… Large, grid connected PV power plants –Multi megawatt scale, optimal sunlight sites (africa, cali etc), distributed by grid Satellite solar power –In space, receive more sunlight, use microwaves to send to earth- too much capital needed Non- domestic PV systems –Roof top, used on site

8. Costs of Energy High capital costs, low running costs Still too expensive Smaller systems more expensive p/ watt 1982- 27$/wp VS 2006- $4/wp 2003- residential system would be approx $8-12,000 per kwp installed (usually 1.5-2kwp) USA US$/ Watt Feb 2007 4.88 Jan 2007 4.88 Jan 2006 4.71 Jan 2005 4.43 Jan 2004 4.45 Jan 2003 4.87

9. What the future holds… Growing at a rapid rate No green house emissions Must become more efficient (leading is 17%) Mass production is needed- market isn’t there yet

10. Future Table 45. Annual Photovolataic Domestic Shipments, 1996-2005 Year Photovoltaic Cells and Modules a (Peak Kilowatts) 199613,016 199712,561 199815,069 199921,225 200019,838 200136,310 200245,313 200348,664 200478,346 2005 p 134,465 Total424,807 a Total shipments minus export shipments. P = Preliminary. Notes: Totals may not equal sum of components due to independent rounding. Total shipments include those made in or shipped to U.S. Territories. Sources: Energy Information Administration, Form EIA-63B, "Annual Photovoltaic Module/Cell Manufacturers