1. Solar Energy Robert Kinzler

2. History of Solar Technologies
1830’s – Solar thermal collector box
1954 – First Photovoltaic Cell
Late 1950’s – Power for satellites
Small consumer electronics
Off-grid power
Government incentives in 1990’s
More recently?

3. Background Information
World’s electricity demand: 20 *109 MWh/yr
US electricity demand: 4.7*109 MWh/yr
Sun supplies ~1000W/m2 to atmosphere
Which roughly becomes 4±2 kWh/m2/day at the surface for most places in the world
This means we would need to recover all the energy that hits km2

4. Basics of Solar Solar energy can be converted into heat or electricity
Air and water heating
Direct electricity and steam generation

5. Pros and Cons Operation produces no pollution
Can have minimal impact on environment
Potentially hazardous fluids
Can kill birds and insects
May require water

6. Limitations of Solar Amount of sunlight is not constant
Varies with location, time of day, time of year, and weather
Large surface area required for useful amounts of energy

7. Solar Thermal Collectors
Heating water
Storage tank

8. Solar Thermal Collectors
Heating Air
Active or
passive

9. Concentrating Solar Power
Parabolic Troughs
Solar Dish
Solar Power Tower

10. Parabolic Trough Looks like what it sounds like
Focuses sunlight on an absorber pipe of transfer fluid
Can focus times normal sun intensity
Reaches temperatures higher than 750oF
Solar Energy Generating Systems (SEGS) in Mojave Desert, CA (354 MW)

11. SEGS

12. Solar Dish Reflects light to a point rather than a line
Tracks sun as in passes
Higher focus than trough
Fluid temperatures higher than 1380oF

13. Solar Power Tower Idea similar to Solar Dish
Thousands of sun-tracking mirrors
Concentrates sun’s energy up to 1500 times normal
Energy losses minimized
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Right:

14. Ivanpah Solar Plant (392 MW)

15. Photovoltaic (PV) Cells
Convert sunlight directly to electricity
4% of the world’s desert could meet all our needs
Generate DC current
Three Generations

17. First Generation PV Cells
Silicon or Germanium
Doped with Phosphorus and Boron
P and N layers
10-15% efficiency commercially
Close to 30% efficient in research

18. Electrical Current
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Right:

19. Band Gap of Silicon (1.11eV)
Shockley-Queisser Limit

20. Second Generation Thin-film solar cells
Amorphous silicon, CIGS, and CdTe
99% absorption in first μm
Can be flexible

21. Second Generation Efficiency of 10-15% Lower material costs
Consumes lots of energy
Scarce resources

22. Band Gaps of Materials Silicon (1.11eV) GaAs (1.43eV) and
CdTe (1.44eV)
CIS(1.0 eV)
CGS(1.7 eV)

23. Cadmium Telluride

24. Third Generation Many kinds
Organic materials
High performance multi-layer solar cells
Quantum Dot (QD) solar cells
Focus on breaking efficiency barrier as well as cheaper, abundant materials

25. Organic Solar Cells Polymer materials Simple, quick and inexpensive
Readily available materials
Roll-to-roll fabrication
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Right:

26. Roll-to-Roll Fabrication
Similar to printing newspapers
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27. Multi-junction Solar Cells
Each layer can absorb light at different wavelengths
Surpasses the 33.7% efficiency limit
Currently up to ~45% efficiency
Expensive materials

28. Quantum Dot Solar Cells
Doped onto a nanostructure which is then connected to transparent electrode
Very thin
Cascade of electrons

29. https://betterarchitecture. files. wordpress

30. Three Generations Overview

31. Photovoltaic Economics

32. Questions?

33. References
"Solar." EIA Energy Kids -. Web. 18 Mar
Madsen, Morten. "Solar- The Three Generations." Web. 18 Mar
Lund, H. et al. "Solar Cells." Web. 20 Mar
Streetman, Ben G.; Sanjay Banerjee (2000). Solid State electronic Devices (5th ed.). New Jersey: Prentice Hall. p. 524.
"Part 2: Solar Energy Reaching The Earth's Surface." ITACA RSS. Web. 21 Mar