Solar

Solar

In spite of the long-term attention and interest paid towards solar energy production, it is still a minuscule percentage (approximately 1%) of domestic energy production. However, compared to other alternatives, it has the most potential for reducing our dependence on fossil fuels.

Key Points

  • In spite of the recent attention to solar power, solar electricity production is still very low and very expensive
    • Only approximately 0.03% of total power generated globally, corresponding to 4 GW in 2008 [5]
    • Even with fast growth, production expected to be only 12 GW by 2010 [5]
    • Compared to fossil fuels, solar tops the chart in terms of cost per unit energy produced [5]
    • Approximately 21 – 30 cents per KWh, compared to 1 – 4 cents per KWh for coal [5]
  • 500 times more energy incident upon US land from solar radiation than 1980-level domestic energy usage
  • Solar Photovoltaic Energy Research, Development, and Demonstration Act of 1978 (Public Law 95-590) had the following interesting points:
    • Objective was to achieve, by 1988, a peak power production of 2000 annual Megawatts peak (MWp) from photovoltaic (PV)
    • According to Ref. 3, US solar power production in 2007 was only 831 MWp
    • Bill also aimed to reduce average cost of installed PV systems to $1/Wp (peak Watt, 1980 dollars) (how does this compare to today?)
    • PV systems have only just recently approached ~$2/Wp, using cadmium telluride thin-film technology instead of crystalline silicon; conventional silicon PV systems are in the ~$4/Wp range [4]
  • Macroscale PV plants would not require significantly more space than existing energy production power plant systems
    • A 200-MW PV plant requires 4x less land area than an equivalent coal plant (including the coal mining area)
    • Similarly, the same PV plant requires 2–5x less land area than an equivalent nuclear plant (including the uranium mining area)
    • Macroscale PV plants could possible address the energy storage challenge more easily by storing hydrogen (generated from water splitting and other techniques) in large tanks, where it is more easy to compress
  • PV on local scale makes the most sense provided energy storage challenge can be addressed at the home/local level
  • Ref. 2 has interesting rule of thumb for solar energy
  • Any energy production techniques using solar have a difficult time matching the energy density of liquid, petroleum-based fuels. This means it is not ideally suited to mobile applications, such as auto transport, unless the energy storage issue can be solved. Solar seems more appropriate for fixed applications, such as homes, offices, or local-scale energy plants.

References

  1. "The Future of Solar Electricity; 1980 – 2000; Development in Photovoltaics", Monegon Report No. M101, Jan. 1980 (Gaithersburg, Maryland)
  2. Equivalent oil requirement for PV: 1 kWh of PV electricity generated at 30% efficiency is equivalent to 0.002 barrels of oil; thus each kWh generated with P-V avoids the use of 0.002 barrels of oil.
  3. "Photovoltaics," wikipedia, http://en.wikipedia.org/wiki/Photovoltaics
  4. "New Low Cost Solar Panels Ready for Mass Production," Industry Week, Sept. 10, 2007, http://www.industryweek.com/readarticle.aspx?articleid=14932
  5. "Photovoltaics Technology Trends," Displaybank Co. Ltd., Gyeonggi-do, South Korea.

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