A few weeks ago, digging around in a storage box that had mysteriously surfaced, I found one of my old notebooks, and when I say old, I mean old, dating back to high school. Amid the random detritus, (and no, I'm not going to get very specific; the lad that was I deserves some privacy of his flailings) there appears a sketch of a parabolic trough, with a heat absorbing pipe at the focus, and little explanatory notes about "salt water" in the pipe, etc.
At the time, I was interested in desalinization, thus the salt water part. I don't know if I swiped the parabolic trough idea from somewhere, or if I came up with it on my own. If it was the latter, I'll note that it's both a fairly obvious idea, but also pretty clever for a teenager.
Photovoltaic cells and panels get the really sexy press, and I'm cool with that, because direct light-to-electricity is very sexy. We're getting very close to the point where photovoltaics are competitive with other methods of electric power generation, and I've already mentioned that covering a hybrid automobile with them could reduce average fuel consumption by as much as 25%. The "pluggable hybrid" is clearly the technological path of least resistance, albeit one that has a lot of political resistance because of its very virtues. I'm not sure how U.S. automakers became captive to the oil industry, but the evidence for it is pretty stark.
Still, photovoltaics are not yet competitive with oil/gas/coal generated electricity. Wind power essentially is competitive, but there is the old tradeoff between capital costs and operating costs (including fuel costs, which are basically zero for wind and solar). More on that in a bit.
It so happens, however, that the use of mirror-concentrated solar energy to generate electricity from standard steam-type turbines is competitive with fossil fuel generated power. Moreover, this isn't some back-of-the-envelope or even "demonstration plant" calculation. This is based on solar thermal electricity (STE) plants that have been generating power for decades. There is a 354-MW Solar Energy Generating Station (SEGS) in California’s Mojave Desert, which is still the world’s largest solar power plant, and it's been around for over 20 years. It uses parabolic troughs that focus heat onto tubes containing synthetic oil, which is then used to superheat steam for turbines.
The Nevada Solar One plant, for example, went on-line in June, 2007 near Boulder City, Nevada, covering a 350-acre site with 760 parabolic concentrators. Solar One is a 64-W plant, built and owned by Solargenix Energy, a subsidiary of Spain’s Acciona Group, will sell electricity to Nevada Power Company and Sierra Pacific Power Company under a 20-year power purchase agreement. It has enough thermal storage power such that it's expected to be able to meet 98% of it's baseload requirements, meaning that it will use gas turbines for backup for only about 2% of its power generating needs. The SEGS plant needs backup power for as much as 25% of its operation.
Notice the origin of the Solar One plant, however: Spain. Spain is currently the World Leader in STE, despite being at the same latitude as New England. But Europe has made high level policy commitments to renewable power generation, while the U.S. has made high level policy commitments to using military power to "secure" oil resources, and denying that atmospheric CO2 buildup has climate change implications.
Another method of STE collection is the "solar tower" design, which puts a bunch of mirrors that focus the light onto a tower containing a molten salt. The large thermal inertia of such a system also allows near continuous power generation.
Nationally, the best places for "harvesting" solar thermal power (and solar power generally) are in the Southwestern states, California, Nevada, New Mexico, and Texas. California would be doing a better job of it were it not for the fact that the California State budget requires a 2/3 supermajority to pass each year, and so is perennially hostage to the California Republican Party, as deranged a crew as I have ever encountered. The CRP is basically for tax cuts and prisons, as nearly as I can tell. I'd quit the Party if I thought it would do any good, but all I'd get for my trouble would be that I wouldn't get their campaign literature any more, and really, someone needs to keep track of these folks.
Anyway, to return to the meat of the matter, the pure economic case for STE, as well as wind power, photovoltaics, and even nuclear power, is complicated by two factors. One is that "deregulation" of the power industry over the past several decades has put its organization and management into such turmoil that no one in authority is willing to take any chances on things like trying new power plant designs and such. All the risk-taking is centered on finance, trading, and how much those at the top can slip into their own pockets without being sent to jail.
The second complication is that the price of fuel over the past several decades has fluctuated wildly, as has the cost of investment capital. All of the renewables (plus nuclear) substitute high initial capital expenditures for lower operating costs, low to zero fuel costs. On the other hand, fossil fuels (and nuclear power) have fairly high "externalities," which is econospeak for "getting someone else to pay part of the price." In the case of fossil fuels, the externalities are such things as local pollution, global climate change, and foreign wars.
In the grand scheme of things, "capital investment" can be used to build things that actually create more goods and services, or it can be used to build things that siphon money from one set of pockets to another. A road, or example, provides a service, while a toll booth on the road pulls money from the pockets of motorists. My own dark suspicion about the current state of the U.S. economy is that it is concentrating on building toll booths rather than new roads.
Spending money on such things as STE power plants could reduce U.S. dependence on foreign energy sources, reduce the environmental damage of mining to land and water (at some cost to desert ecosystems, I'll stipulate that). It could, in short, create useful capital rather than mere "transfer payment" capital.
Which, again, may be one of the reasons why some people are against such things.