Solar Thermal Heats Up

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Other companies, such as Brightsource Energy, have also developed solar thermal technology using central towers and boilers. But what's new about eSolar's approach, says Daniel Englander, is that the mirrors are smaller and cheaper to make and install, thus requiring more sophisticated control software.

Utility-scale thermal solar plants have been around for decades, the largest of which is the set of Kramer Junction plants in the Mojave Desert that produces 350 megawatts of peak power for Southern California Edison. But its massive trough-shaped panels, which harness the sun, are expensive to make and install, in large part because they require so much steel to support the parabolic-shaped glass panels.

However, a large amount of new thermal solar power capacity is being planned using newer technology. Currently, there's more than eight gigawatts of thermal solar capacity being promised to U.S. utilities; how much of that will actually get built is unclear. "A lot of these contracts in California that the utilities are signing aren't with an eye to actually building," Englander says. "A lot of times, it's just a good-faced effort to show that they're engaged with renewable energy."

Later this month, eSolar's 24,000-panel plant in Lancaster, CA, is set to begin supplying its power for the grid. However, since the plant is self-financed and company operated, no one outside eSolar will be able to verify the real costs of producing the electricity.

From then on, though, eSolar won't be building its own plants. NRG Energy, based in Princeton, NJ, will purchase eSolar's technology and build, finance, and operate the planned 500 megawatts. NRG currently operates 24 gigawatts of power capacity at dozens of plants powered by a full range of energy sources. Michael Liebelson, NRG's chief development officer for low carbon technology, says that he chose eSolar because "it is the lowest cost of all solar solutions."

In a separate but even larger deal, eSolar has signed a similar pact with ACME Tele Power of India for one gigawatt of capacity--enough to power hundreds of thousands of homes.

So far, Gross has raised $170 million from various venture firms and strategic partners, including investments from NRG, ACME, and Google.