But today's photovoltaic cells, the kind that cover rooftops in sunny areas, are too expensive to use on an industrial scale. Their cost would be off the scale for that, Eskelsen said.

However, concentrated solar power systems, which use mirrors to focus the sun's light, are not as expensive as photovoltaics.

In southern California's Mojave Desert, nine gigantic solar power plants are to be linked together into a system that can produce about 553 megawatts of electricity. The "Mojave Solar Park" system uses an extensive network of curved mirrors that focus the sun's heat on long pipes filled with fluid. The heated liquid turns turbines that produce electricity, which will be sold to Pacific Gas and Electric, San Francisco.

The system, being built by Solel Solar Systems, Israel, "is now the world's largest single solar commitment," says a PG&E press release.

Intense desert sunlight and the fact that comparatively little rain falls in the Mojave, help make the system successful. Yet even concentrated solar power may be too expensive to offset much of the national demand.

A California Energy Commission draft report, dated June 2007, says existing generating costs for coal-powered plants averages just below $40 per megawatt-hour, while cost of new power plants would rise to just above that. New geothermal systems would cost more than $60 per megawatt-hour; new wind farms at Class 5 sites would boost the price of power by a few more dollars per megawatt-hour, and new nuclear plants would cost around $75 per megawatt-hour.

The "concentrating solar" system, like that used in the California desert, comes in at an estimated $180-plus per megawatt-hour.

New capacity is costly

"The current cost of Rocky Mountain Power's generation is around $35 a megawatt-hour," Eskelsen said. But if the utility were to build a new coal-fired plant, using the efficient pulverized-coal technology, "that would cost you $60 to $65 a megawatt-hour."

Compared with recent years' prices, "the cost of materials is huge — the cost of steel, concrete, all metals." Even adjusted for inflation, the price rise for materials has been spectacular, he said.

"In 2003 you could get a wind turbine for $1 million. Now it will cost you $2 million, and almost all of this is for the cost of steel and concrete." According to Rocky Mountain Power, in 2000, steel cost $425 per ton, and in 2007 it was $893 per ton.

"China and Europe are competing not only for materials and finished manufactured goods, but also for engineering and engineering and labor expertise to actually build these projects," Eskelsen said.

"Anything we build today is going to be at least twice as expensive as what we're using now."

---

E-mail: bau@desnews.com