Thermal solar systems receive sunlight, concentrated in a parabolic dish trough or in a tower, which is then converted to electricity by a heat engine and electric generator. A 1978 study found that the materials required for thermal solar projects were 1,000 times greater than for a similarly sized fossil fuel facility, creating substantial incremental energy consumption and industrial pollution.¹⁶⁸ An updated study into the total fuel-cycle environmental costs of solar has been investigated but not rigorously pursued. The mentality, according to one participant who wished to remain anonymous, is "keep the closet closed so you don't know what is in there."¹⁶⁹ However, an energy specialist at the California Energy Commission calculated that the production of concrete per thousand megawatts of nameplate solar capacity (a proportionally high input) results in carbon emissions equivalent to 10 billion cubic feet of combusted natural gas -- approximately a year's worth of fuel for a similarly sized gas-fired plant.¹⁷⁰

Thermal solar installations have had a disappointing past. Solar One, a 10-megawatt solar thermal project operated by Southern California Edison for high demand periods, closed in 1988 after six years of operation. The facility, 80 percent of which was funded by the U. S. Department of Energy, was so experimental and expensive that no cost per kwh was publicly revealed.¹⁷¹ In addition to heavy land requirements, bird deaths ("the birds died primarily from collisions with the picture-like surface of the heliostats") are as much as 10 times the kill at Altamont Pass per megawatt, although endangered species and other high profile birds have not been at risk.¹⁷²

Solar Two, a $48 million, 10-megawatt demonstration project cofunded by an industry consortium led by Southern California Edison, the Department of Energy and the California Energy Commission, entered production in 1996. In place of a parabolic dish, this project uses a receiver tower where the concentrated heat from the field mirrors (called heliostats) is converted to electricity. Its $4,000 per kilowatt installed cost -- which would have been as much as $14,000 more per kilowatt if Solar One's equipment had not been utilized¹⁷³ -- is still between five and 10 times greater than a gas-fired plant under current technology. The plan to generate power at between 7 and 8 cents per kwh will be virtually impossible at this capital-cost level.¹⁷⁴ An annual operating cost of $3 million virtually ensures a shutdown in 1999, the year federal subsidies are scheduled to terminate.

The 1,900 mirrored panels, each measuring over 100 square yards, come out to 17 acres per megawatt of capacity.¹⁷⁵ That is 50 times greater than a similarly sized gas-fired facility on a nameplate basis but 150 times greater on a generation basis. And unlike wind power, the land concentration of solar farms is very dense.

These concerns led a Worldwatch Institute study to conclude:

Solar Two looks good on paper, and it is expected to provide steady baseload electricity as well as late afternoon peaking capacity, but the future of all the central solar generators is in doubt. They are expensive to build, their very scale escalates financial risks -- as with nuclear power -- and their massive height (in excess of 200 meters) may attract opposition.¹⁷⁶

The economic plight of central-station thermal solar was revealed with the bankruptcy liquidation of LUZ International in December 1991. LUZ, which was responsible for virtually all solar capacity in California, blamed lower fossil fuel prices for its plight.¹⁷⁷ A restart company utilizing LUZ technology, heavily subsidized by private and public Israeli interests, hopes to lower thermal solar costs to 7 to 7.5 cents per kwh after the turn of the century.¹⁷⁸ However, gas-fired technology, the Department of Energy predicts, will be around one-half as much,¹⁷⁹ and this estimate has already been exceeded.