The potential market for large, centralized solar power plants is far larger than that for rooftop systems, Khosla Ventures founder Vinod Khosla said in a press meeting at the Solar Power conference in San Jose.

“I think rooftops will be difficult,” he said Tuesday afternoon. “Rooftops could make 10 percent of the market. Unless we get better storage, PV [solar-electric power] won’t happen residentially; it will happen centrally.”

He estimated we could get up to 90 percent of the power we need from centralized renewables, which are “getting very competitive” with natural gas and other forms of fossil energy.

But rooftop systems make up the lion’s share of solar power today. In fact, solar power is often viewed as the quintessential form of distributed energy, or energy that’s made where it’s used. And solar advocates often tout the advantages of distributed energy.

“Centralized solar is good in the Southwest and other places, but distributed solar works much better in most of the country,” said Jeffrey Wolfe, CEO of residential solar integrator GroSolar, referring to the United States.

Greg Gaucher, a technical salesperson with solar company Menova Energy, agreed. “The problem with a centralized system is you lose energy when it’s transmitted,” he said. “It’s way more efficient to have a bunch of independent systems, so if one fails, the others are not affected.”

Mr. Khosla, however, said centralized power is simply cheaper. “I believe thermal can be more cost-competitive than natural gas,” he said. Thermal solar-electric technologies use the sun’s heat, instead of its light, to make power.

No doubt a central model using thermal solar power could be cheaper, agreed Rhone Resch, president of the Solar Energy Industries Association, which is hosting Solar Power.

“But the advantage of distributed [solar] is that you need no transmission lines,” he said. Still, he added, “I don’t think it’s either/or, I think it’s both. Both are exciting technologies, and with the amount of money going in, we’re going to see both grow.”

Ron Kenedi, who heads Sharp’s solar operations in the Americas, takes a similar stance. “We think it’s all important—central, distributed, and power at the point of use, like in lighting and signage,” he said. “You have to use the right product for the right job, but we’re bullish on every form of solar except maybe garden lights.”

Sharp, the world’s No. 1 solar manufacturer showed off a solar concentrator at the exhibition, along with a residential solar panel. Concentrators, which could be used in centralized “large field” applications, use mirrors or lenses to concentrate sunlight onto smaller solar cells, and Mr. Kenedi said they are coming.

But Mr. Wolfe said he would argue with Mr. Khosla’s 90 percent to 10 percent ratio. He believes distributed solar has more potential than centralized power, he said.

Distributed solar supports the grid and provides more economic opportunity, he said. “You need to add less transmission capacity, and if it’s centralized you need to add more and more transmission capacity,” he said. He added that from a business standpoint, “the higher margin system comes from distributed power.”

Of course, 10 percent share of the energy market is nothing to sneeze at. Solar power currently makes up one half of one percent of the U.S. market, Mr. Khosla said. Mr. Wolfe agreed: “Ten percent is big business.”

Contact the writer: jkho@redherring.com

del.icio.us

Digg this