Matthew Miller wrote: > On Wed, Apr 26, 2006 at 04:55:02PM -0700, Bob Axtell wrote: > >> 1. We have calculated that a solar plant that can capture 5 square miles >> of desert sunlight will generate enough electricity to >> meet the electrical needs of the USA even as the needs expand for the >> next 50 years. >> > > This is very old data, published in the 80s. I am quite certain that it is correct. Lets see... ya know, I think I misspoke, I think it is 5 miles square, not 5 square miles. That is then a square, 5mi by 5mi, or 25 square miles. My calculator says that 25sq miles contains 2,589,998.5 square meters. At 740 watts per square meter, that is 1,926,598 KW or 1926.6 MW. Barely enough for Greater LA, methinks... Doesn't look like enough to me, either... Looks like it needs to be maybe 10 times that... I need to go dig this outa my old paper files. > I have to take issue with this number of square miles. It seems hopelessly > optimistic. > > >From the total > 2004 generating capacity was 963E9 Watts. > has the best case value of 1020 > W/m^2 of solar energy reaching the ground. > > So. Arizona averages yearly 740 W/meter^2. In summer it probably gets close to 1020. But its major advantage is that there are very few overcast days, the reason why So Arizona has 5 observatories within 50 miles of Tucson. > Using this info, at least 365 mi^2 would be needed to power the U.S., and > this is assuming 100% efficiency. A power generation faculty at 50% > efficiency would be 40x40 miles. This would be the greatest engineering > project mankind ever attempted! I'm all for this, but I'm skeptical whether > solar on this scale will beat nuclear on economics alone. > Nuclear power has no economics. Nuclear power is never paid for,; we will pay for it generation after generation in perpetuity; sorta like an expensive cemetery. But if you are looking for the loose screw, it is that the US power grid would be unable to accept even a fraction of the plant's output, because it is so decadent. Rebuilding the grid would be the most costly task. > Of course I've been very optimistic here, much more that 700 mi^2 will be > needed. Multiple solar collection faculties as well... > Yes, NM could take a few, Arizona many, because most of Arizona is unused Indian land, just dust and cactus. But AZ has an advantage in that the Bay of Baja could provide cooling water, pumped about 50 miles. Mexico would certainly assist, in order to get cheap electricity in exchange. > Let's do it. Human kind need challenges any way. > It beats another nuke plant. Lets do! --Bob > Matthew > > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist