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Name: Jerry F.
Status: Other
Age: 50s
Location: N/A
Country: N/A
Date: July 2004


Question:
"The US Department of Energy estimates that a 10-mile by 10-mile square of solar panels located in a place such as Nevada would generate enough electricity to meet all current power needs of the US." In the past week I have seen or heard this quote twice, it intrigues me. Is this a true statement? If so, what report is this from, how can I acquire a copy of the report? If there is such a report, is there any plan to act on it?



Replies:
Jerry,

I am not familiar with the report to which you refer. It sounds encouraging. However, solar panels are not very efficient and it would indeed require quite a large array to generate that much electricity. Nevertheless, I am very keen on developing alternative ways to generate electricity -- solar, wind, geothermal, tidal, and others -- so that we might move toward a hydrogen-based energy economy derived from hydrogen produced via the electrolysis of water. Should that day ever arrive, we would have more than enough domestic oil to meet manufacturing needs and not have to waste it as a fuel to drive the wheels of industry. Now, how do we get the folks with the influence to allow it to happen?

Regards,
ProfHoff 883


This is only about 1% of annual U.S. consumption. Other factors render this option even less optimistic AS A NATIONAL SOLUTION.

1. The solar flux is total energy at all wavelengths. The atmosphere, clouds, and conversion to useable energy forms reduces the amount of energy that reaches the surface of the earth significantly less than the Solar flux.

2. No existing solar conversion technology can make use of all the incident wavelengths, and even then the conversion efficiency is small. This is a technological deficiency not a physical one, and there is a lot of research being done to improve existing conversion technologies, and find new ones.

3. There are significant losses in the distribution of power from the source to the user (electrical resistance in the electrical grid etc.)

4. The solar flux is an average. It can vary (even in Nevada) from cloudiness, season etc., so some sort of energy storage system has to be operating to take up the slack during low flux periods.

5. Building a 10 square mile solar panel is an engineering feat of the first magnitude. It also has to be fail-safe -- disruptions would cause major problems.

Having said all that I think that solar energy combined with wind technology could be very efficient on a limited basis -- say to supply a portion of power to a farm, industry, or even a shopping center. There is much energy "out there" to be tapped in addition to "fossil fuels". However, there are also the political problems. Oil producers and refiners are not all that enthusiastic about replacing their major product -- short sighted (yes) but real.

Vince Calder


That number is not right. Assuming 10% overall efficiency, and sited in the Nevada desert, one can calculate a panel area about 90 miles square would be required. Solar insolation is about 5kWhr/day and electric demand in 2000 was about 3.6 terawatt hours. The actual area covered by the installation would be several times larger.

Bob Erck


Yes. See http://www.eere.energy.gov/solar/myths.html

Tim Mooney



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