Nature recently ran an article ($ub. req’d) on “Energy alternatives: Electricity without carbon.” Like most discussions written by people who don’t follow clean energy closely, the article lumped baseload solar (also known as concentrated solar thermal power) in with solar PV and generally treated it as an afterthought.
Here is everything that they wrote about baseload solar:
Solar cells are not the only technology by which sunlight can be turned into electricity. Concentrated solar thermal systems use mirrors to focus the Sun’s heat, typically heating up a working fluid that in turn drives a turbine. The mirrors can be set in troughs, in parabolas that track the Sun, or in arrays that focus the heat on a central tower. As yet, the installed capacity is quite small, and the technology will always remain limited to places where there are a lot of cloud-free days — it needs direct sun, whereas photovoltaics can make do with more diffuse light.
Costs: The cost per kilowatt-hour of concentrated solar thermal power is estimated by the US National Renewable Energy Laboratory (NREL) in Golden, Colorado, at about $0.17 …
Capacity: Earth receives about 100,000 TW of solar power at its surface — enough energy every hour to supply humanity’s energy needs for a year … Theoretically, the world’s entire primary energy needs could be served by less than a tenth of the area of the Sahara. [This was actually all part of their PV analysis.]
Advantages: The Sun represents an effectively unlimited supply of fuel at no cost, which is widely distributed and leaves no residue. The public accepts solar technology and in most places approves of it — it is subject to less geopolitical, environmental and aesthetic concern than nuclear, wind or hydro, although extremely large desert installations might elicit protests …
Both photovoltaic and concentrated solar thermal technologies have clear room for improvement. It is not unreasonable to imagine that in a decade or two new technologies could lower the cost per watt for photovoltaics by a factor of ten, something that is almost unimaginable for any other non-carbon electricity source.
(Nature has no comment on the price of baseload solar, which could easily drop 30 percent to 50 percent over the next several years, making it the cheapest form of carbon-free baseload power.)
Disadvantages: The ultimate limitation on solar power is darkness … Some concentrated solar thermal systems get around this by storing up heat during the day for use at night (molten salt is one possible storage medium), which is one of the reasons they might be preferred over photovoltaics for large installations …
Another problem is that large installations will usually be in deserts, and so the distribution of the electricity generated will pose problems. A 2006 study by the German Aerospace Centre proposed that by 2050 Europe could be importing 100 GW from an assortment of photovoltaic and solar thermal plants across the Middle East and North Africa. But the report also noted that this would require new direct-current high-voltage electricity distribution systems …
Verdict: In the middle to long run, the size of the resource and the potential for further technological development make it hard not to see solar power as the most promising carbon-free technology. But without significantly enhanced storage options it cannot solve the problem in its entirety.
My verdict: Quite a lame treatment, for a leading science journal. Baseload solar could easily be a major player in the short to middle run if we’re smart, perhaps the single biggest source of new carbon-free generation. It certainly deserved its own section, especially given that “ocean energy” got its own section.
This post was created for ClimateProgress.org, a project of the Center for American Progress Action Fund.
