Rectifying Myths Related to Solar Energy

1. Rectifying Myths Related to Solar Energy Joshua Pearce E Sci 497C The Pennsylvania State University

2. Myth 1: All Solar Cells are the same

3. GaAs and other III-V’s • Advantages: • Awesome efficiencies (30%+) • Disadvantage: They simply cost too much. (only good for NASA) • Material ---wafer----cost • c-Si 8” ~$100 • GaAs 4” ~$300 • InP 3” ~$800

4. CuInSe2 • Advantages: • High Efficiency in lab cells (~17%) • Disadvantages: • Instability in hot/wet environments • High temperature deposition • Un-established deposition technology • The availability of Indium (silver)

5. CdTe • Advantage: • High Efficiency in lab cells (~16%)- prototype • Disadvantage: • Toxic material

6. Dye sensitized TiO2 • It is “neat” (~10%) but…. • Potential instability • Limits on maximum operation temperature • Evaporation problems • Cost • Far from commercialization

7. Crystalline & Polycrystalline Silicon • Advantages: • High Efficiency (~25%) • Established technology (The leader) • Stable • Disadvantages: • Expensive production • Low absorption coefficient • Large amount of highly purified feedstock

8. Crystalline Silicon Amorphous Silicon

9. Amorphous Silicon • Advantages: • Cheaper than the glass, metal, or plastic you deposit it on • Established technology • Low-cost substrates • Excellent ecological balance sheet • Disadvantages: • Only moderate stabilized efficiency (~13%) • Instability- It degrades when light hits it :(

10. Abundance of all raw materials • The amorphous silicon cells manufactured from one ton of sand could produce as much electricity as burning 500,000 tons of coal.

11. Myth 2: Solar cells use more energy to produce than they generate over their lifetime

12. For cells in production now the energy payback is between 6 months and 3 years! (full system 2-5 years) • Solar cells produce enough energy to reproduce themselves ~40 times!! • For Built-In PV systems in which solar cells replace a buildings structure the energy payback can be measured in days!

13. Built in PV

14. Myth 3: There is not enough land

15. The total solar radiation falling on the earth is 1.2x1014kW, which is roughly 10,000 times current world consumption. • The fossil fuel production of the entire world could be replaced by hydrogen generated by photovoltaic arrays on 53 million hectares of arid land (less than 2% of the area of the world’s deserts).

16. Even brighter in the U.S. • Solar Cells covering 0.3% of the land in the U.S. (1/4 of the area currently occupied by railroads), could provide all of the U.S.'s electricity needs.

17. Distributed energy source • Located near the consumer in order to eliminate transmission losses (which can be higher than 50% on modern grids). • Panels could be placed on roofs, built into roofs, building facades, carports, highway sound barriers, etc. • Any surface which is exposed to sunlight is fair game.

18. Carports

19. Myth 4: Switching to solar cells as our primary energy source will cause considerable unemployment

20. A 1997 Pembina Institute report found that for every million dollars invested: • 36.3 jobs are created in the energy efficiency sector • 12.2 in the renewable energy sector In conventional energy, an average of only 7.3 jobs are created.

21. PV: net job producer! • Jobs created with every million dollars spent on: • oil and gas exploration: 1.5 • on coal mining: 4.4 • on producing solar water heaters: 14 • on photovoltaic panels: 17

22. Coal only employs 80,000 • It is predicted that by 2010, approximately 70,000 new jobs could be created as a result of the increased demand for photovoltaic, solar hot water, and related solar energy systems through the installation of only one million solar energy systems. (3%)

23. Myth 5: Solar cells will not make economic sense until the distant future.

24. Today it makes economic sense • Now it makes sense for remote sites that are too far from power, or where the power is too unreliable. • Costs for power lines range from $8000 to $75,000 per mile. • As a general rule, if you are more than 1/2 mile from a line, solar is probably the best alternative.

25. Where solar can’t be beat now • In areas that have grid power, where the cost of tearing up the streets and/or other construction are expensive.

26. Coast Guard Stations • 1400 U.S. Coast Guard stations redesigned

27. Bus stops and emergency phones

28. Street Lights and Phones

29. Department of Environmental ProtectionCambria Office – $ Payback time 5 years for PV

30. And costs continue to drop

31. Real World Economics • Price reduction of 7.5%/yr during which the average worldwide production of modules increased by 18%/yr. • Economy of scale -- direct competition with fossil fuel as an energy source it is generally agreed that 100MWp PV plants must be constructed

32. When will this happen? • For example, N. Mori, the executive managing director of the Photovoltaic Power Generation Technology Research Association, predicts that Japan will begin producing 100MWp/yr factories between 2003 and 2004. • The U.S. ~2005-7

33. 200,000+ homes in the U.S. use some type of photovoltaic solar technology-and the market expanded over 52% last year The Future is Solar