Bill Gross's Solar Breakthrough

Bill Gross's Solar Breakthrough

"We are producing the lowest cost solar electrons in the history of the world," Bill Gross is telling me. "Nobody's ever done it. Nobody's close."

Bill Gross is nothing if not an enthusiast, which makes him a great salesman for whatever it is he happens to be selling. A lifelong entrepreneur, a longtime evangelist for solar energy and the CEO of eSolar, a Google-funded startup that designs and develops concentrating solar power (CSP) projects at utility scale, Gross is one of the most interesting business people I've known.

I met Bill in 2002, when I wrote a critical story about him for FORTUNE –- investors in Idealab, his Internet incubator, were suing him after the dot-com bubble burst –- and although he and his wife, Marcia Goodstein, were more than mildly irritated with me then, we've reconciled and I now count myself as an admirer of Bill's. He's always got a million things going on, some of them slightly nutty, but all of them interesting. He's in the robot business with a company called Evolution Robotics and he's the founder of Aptera, a very cool electric car company (in which Google has invested) that I wrote about last spring.

Today, Bill and eSolar are staging a grand opening for eSolar's first plant, called the Sierra SunTower, located in the southern California desert near Lancaster. Below are a couple of photos, taken by Bill, from a helicopter ride over the plant on July 3. He sent them to me via Picasa, the photo sharing site now owned by Google, which he founded back in the 1990s. Like I said, he's a serial enterpreneur. (Bill also invented the idea of paid search, but that's another story.)

In any event, this eSolar plant is a big deal, according to Bill, because it is producing solar energy at a lower cost than other solar thermal plants and at a much lower cost than utility-scale solar photovoltaic arrays. Concentrating solar power (CSP), also known as solar thermal power, produces energy by using mirrors or lenses to focus the sun's heat and boil liquids that become a heat source for a steam turbine. Climate-change expert Joseph Romm, writing in Salon, opined last year that solar thermal

will be the most important form of carbon-free power in the 21st century. That's because it's the only form of clean electricity that can meet all the demanding requirements of this century.

Solar thermal technology has been deployed commercially for decades, but Gross tells me that eSolar has been able to drive costs down by mass-producing and deploying thousands of small mirrors across fields that track the sun and reflect its heat back at a thermal receiver mounted on a tower. "Our breakthrough is lots and lots of small mirrors, and lots and lots of software to control them," he says. The Sierra SunTower alone uses 24,000 mirrors, made by a contract manufacturer in China. You can read about the technology and see pictures here on eSolar's website.

eSolar's Sierra Sun Tower Plant, with panels arrayed to display a message. solar panels

Through a power purchase agreement with Southern California Edison, the Sierra SunTower plant will supply 5 MW of clean energy to the grid. That's not a lot, but it's just the start of big things to come, Gross says.

While Google is eSolar's best-known investor, two other big backers of the company—an Indian energy and telecom firm called the ACME group and Princeton, N.J.-based NRG Energy—are ready to step up their commitment to solar thermal, now that they can measure the cost and efficiency of eSolar's technology under real-world conditions.

Acme, which invested $30 million in eSolar, has agreed to invest another $20 million, Gross told me. ACME has said it plans to build, own and operate up to 1 GW of solar thermal plants over the next 10 years using eSolar's designs and mirrors. Construction will begin this year.

NRG, meanwhile, plans to start building a 92 MW plant in New Mexico as soon as it wins regulatory approval, Gross says. NRG has agreements with eSolar to develop solar power plants with a total generation capacity of up to 500 MW at sites within California and across the southwest.

I emailed David Crane, the chief executive of NRG, to ask him about eSolar. He was on his way to today's ceremony and emailed back:

Bill Gross is the kind of can-do visionary–with the innate ability to find the "winning" disruptive technology of the future–who we, at NRG, want to work with as we seek to deploy a new generation of sustainable and climate-friendly power technology in this country.

It's impossible for me to evaluate Gross's claims for his technology. But the fact that big companies are willing to invest capital in eSolar -- at a time when capital is scarce -- leads me to believe that Bill is, once again, onto something big.

"We have a cost-effective, no-subsidy solar power solution and it's for sale, anywhere around the world," he says.

Bill Gross and David Crane are regulars at FORTUNE's Brainstorm: Green conference about business and the environment, which I co-chair, and I'm pleased that they'll both be back as speakers next year.

eSolar's Sierra Sun Tower Plant, with another message. solar panels