In the last 24 hours, two power producers ordered up a gigawatt of solar power. That's twice the total solar capacity the United States had installed in 2007.

PG&E, a California utility, and NRG, a national independent power producer, announced plans to build 500 megawatts of solar power each. NRG is partnering with Google.org-backed eSolar, a startup incubated by the legendary venture capital firm, Idealab, that is pursuing solar thermal power which uses mirrors to turn liquid into steam that drives a turbine. Meanwhile PG&E will be investing in photovoltaics, which directly convert light into electricity.

The Solar Electric Power Association particularly celebrated the latter move, which they said heralded a new era for solar energy in which utilities, not individual consumers, would be the "most important customer" for the industry.

The original bailout bill, passed last year and filled with energy provisions, changed the law so that utilities like PG&E became eligible to receive the 30 percent investment tax credit for solar projects. Five utilities from New Jersey's PSE&G to San Diego Gas & Electric have now announced plans for utility-owned solar projects.

"Utility companies around the U.S. are exploring ownership of solar projects now that they have access to the [tax credit]," said Julia Hamm, the Solar Electric Power Association's executive director.

The two announcements highlight the ongoing strength of renewable energy, despite the tough economic times. With most industries falling apart, tax incentives and the risk of carbon legislation continue to push renewable energy forward, even as some individual projects and companies experience trouble.

*Image: A rendering of an eSolar modular 46 megawatt plant. *

See Also:

WiSci 2.0: Alexis Madrigal's Twitter , Google Reader feed, and project site, Inventing Green: the lost history of American clean tech; Wired Science on Facebook.