Solar Thermal Electricity, humanity’s saviour?

April 16, 2008 at 5:52 pm (Green Energy, Green Technology)

Slashdot points to an article by Joe Romm, who is considered “one of the world’s leading experts on clean energy, advanced vehicles, energy security, and greenhouse gas mitigation” discussing the merits of solar thermal energy.

Frankly, I have never seen a better article on this and is an eye opener to me.

Mr. Romm understands the issue very clearly because the title of the article is “The technology that will save humanity” and not the other way round of saving the Earth. As Atanu Dey pointed out to me sometime back, it is us; humans; who need saving and not the Earth.

Romm after the excellent start, goes on to explain the constraints of a good carbon free source of energy.

This electricity must meet a number of important criteria. It must be affordable: New electricity generation should cost at most about 10 cents per kilowatt hour, a price that would probably beat nuclear power and would certainly beat coal with carbon capture and storage, if the latter even proves practical on a large scale. The electricity cannot be intermittent and hard to store, as is energy from wind power and solar photovoltaics. We need power that either stays constant day and night or, even better, matches electricity demand, which typically rises in the morning, peaks in the late afternoon, and lasts late into the evening.

This carbon-free electricity must provide thousands of gigawatts of power and make use of a low-cost fuel that has huge reserves accessible to both industrialized and developing countries. It should not make use of much freshwater or arable land, which are likely to be scarce in a climate-changed world with 3 billion more people.

Solar electric thermal, also known as concentrated solar power (CSP), meets all these criteria. A technology that has the beauty of simplicity, it has proved effective for generations. As the Web site of CSP company Ausra illustrates, solar thermal has a long and fascinating history.

He then goes on to provide a good history of the technology and its use in the last century and the developments in this century.

The key attribute of CSP is that it generates primary energy in the form of heat, which can be stored 20 to 100 times more cheaply than electricity — and with far greater efficiency. Commercial projects have already demonstrated that CSP systems can store energy by heating oil or molten salt, which can retain the heat for hours. Ausra and other companies are working on storing the heat directly with water in the tubes, which would significantly lower cost and avoid the need for heat exchangers.
[...]
Since all three remaining presidential candidates endorse a cap on carbon dioxide emissions coupled with a system for trading emissions permits, carbon dioxide will likely have a significant price within a few years. And that means the economics of carbon-free CSP will only get better. Improvements in manufacturing and design, along with the possibility of higher temperature operation, could easily bring the price down to 6 to 8 cents per kilowatt hour.
[...]
CSP makes use of the most abundant and free fuel there is, sunlight, and key countries have a vast resource. Solar thermal plants covering the equivalent of a 92-by-92-mile square grid in the Southwest could generate electricity for the entire United States. Mexico has an equally enormous solar resource. China, India, southern Europe, North Africa, the Middle East and Australia also have huge resources.

Solar has the biggest potential of all and looks like thermal electricity is better than PV.

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