Go Solar Power For Homes

2 Comments so far »

1. by Sam Deane, on March 9 2010 @ 3:37 am

   

   There are a number of factors here that you have to keep in mind. Solar photovoltaic panels are about the lowest efficiency for making solar generated electricity with an efficiency of about 14 to 18%. They would take up more area.

   Parabolic dish solar thermal concentrators are about the most efficient with the max at about 31% however this is measured from received light and not land area. 1

   Parabolic trough collectors are less efficient but their tracking mechanism simpler than the parabolic dish or the power tower reflectors as it only needs to be in one plane. For required area see below: 2

   The power tower may have the greatest potential as it is easily adapted to a hybrid co generation facility with natural gas providing heat to steam boilers when the sun doesn't shine.3

   And the solar chimney design may allow for several different usages of the same land. These are conceived on the most massive scale. 4

   All solar thermal installations have several options to store heat for times when the sun doesn't shine.

2. by Sam Deane, on March 9 2010 @ 3:37 am

   

   Depends how sunny the area is. California solar power plants can produce about twice what German ones do, for example.

   Using Californian solar power output (~2200kWh/yr-kWp) and UK average household electricity consumption (4400kWh/yr), you need approximately 2kWp of solar power in the Californian desert to produce enough annual power for a UK house. Of course, this doesn't make electricity during the night, so you need some kind of backup, but let's run with this for now.

   A residential city may contain 50,000 households. To power just the households, you'd need approximately 100MWp of solar power, or 2.5 times the area of Waldpolenz solar park in Germany:
   http://renewableenergydev.com/red/solar-…
   Which is about 2km x 1km and electricity costs about $0.40 per kWh. Very expensive, but it would be about half the price in California and prices are falling.

   So land area would be about 5 sq km or 5 million sq metres – about 100sq m per household. You could fit the majority of it on people's roofs.

   I used FirstSolar CdTe solar panels as an example because they are currently the cheapest, but they are not as efficient as CIGS or silicon panels. You could reduce the land area used by about 40% by switching to more efficient panels, but then you'd approximately double the cost. Prices are continuing to fall, and I believe the FirstSolar Sempra project in California has been calculated at 7.5cents per kWh which isn't too bad – a few more years of falling prices and solar will be competitive.

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