Breaking Down Big Solar


This month's cover story provides a retrospective on the U.S. Department of Energy's (DOE) loan-guarantee program, which – as the industry is well aware – is currently winding down.

But the program is not quite done, yet; as a June 22 announcement makes clear, the DOE still has a few surprises up its sleeve.

Whereas previous loan guarantees for solar projects have historically favored massive utility-scale PV and concentrating solar power (CSP) plants, the agency's most recent loan-guarantee commitment – for a $1.4 billion loan – supports a rooftop PV initiative called Project Amp.

Project Amp calls for the installation of 733 MW of PV on 750 industrial roofs owned and managed by ProLogis in up to 28 states and Washington, D.C. NRG Energy will serve as the project's lead investor, and Bank of America Merrill Lynch has signed on as the lender.

While the company names are big, the individual projects themselves are small compared to the 1 GW Blythe solar power plant, for instance. Yet Project Amp is a notable and commendable alternative.

First, large utility-scale solar plants – even those backed by the DOE – continue to face countless permitting delays, miles of administrative red tape, and lawsuits from environmentalists, cultural groups and a range of other project opponents.

Of course, no one expects that installing PV on existing rooftops rather than in the desert Southwest will eliminate all administrative hurdles or local objections. But we can almost certainly say that some of the main issues that have choked huge plants' development – e.g., potential harm to desert tortoises or encroachment upon pristine or protected lands – will not pose a problem for Project Amp's installations.

Unlike many other similarly sized projects, the arrays will produce power that will be delivered directly to the electrical grid rather than to the host buildings. According to the DOE, this electricity will amount to more than 1 million MWh annually.

Project Amp is intended to help the U.S. take another step toward meeting the DOE's SunShot Initiative, which calls for cost-competitive solar power by the end of the decade. In his article on page 74, Aide Solar executive Raymond Wiley stresses that for the U.S. to meet this goal, cost-reduction must take place across the board – including during solar deployment.

Under this broad definition of efficiency, is rooftop PV necessarily ‘more efficient’ than large PV or CSP plants? The answer is up for debate, but for now, we should be encouraged by the government's support of different paths to ever-greater efficiency.  Â

This Sun Dial column was originally published in the July 2011 issue of Solar Industry.

Editor's note: To submit your own contribution to Viewpoints, email Jessica Lillian at

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