Green Wombat

photo: Todd Woody

In The New York Times special Energy report, I write about how community solar power plants offer residents a chance to own photovoltaic arrays without putting panels on their roofs — or cutting down trees:

DAVIS, Calif. — In this environmentally conscious college town, thousands of bicyclists commute each day through a carefully cultivated urban forest whose canopy shields riders and their homes from the harsh sun of this state’s Central Valley.

The intensity of that sunshine also makes Davis an attractive place to generate clean green energy from rooftop solar panels. And therein lies a conundrum. Tapping the power of the sun can also mean cutting down some of those trees.

“Davis has spent many, many decades getting trees planted and improving energy efficiency by virtue of shade trees that cool houses,” said Mitch Sears, the city’s sustainability program manager. “But if you want solar energy, it’s not rocket science that you need the sun.”

Now a San Francisco company, CleanPath Ventures, is promoting a solution to allow homeowners to keep their trees and go solar at the same time. CleanPath plans to expand its existing solar farm on the city’s outskirts and then sell “garden plots” to homeowners who would own the electricity generated by their patch of photovoltaic panels. Apartment dwellers and other residents whose homes are not suitable for rooftop solar arrays would also be able to own a piece of the power plant.

“If you moved down the block, you’d take the electricity production with you just like if you make an investment in a community garden, wherever you live you’ll benefit from what’s grown in the garden,” said Matt Cheney, a longtime financier of renewable energy and the founder of CleanPath Ventures.

Community solar power plants are seen as a way to expand the availability of renewable energy while taking advantage of the economies of scale that result from installing thousands of solar panels in a central location rather than scattered on thousands of individual homes.

“To get the energy benefits of solar there’s no reason to drill holes in a roof,” said Jim Burke, manager of the SolarShares program for the Sacramento Municipal Utility District, which serves the region surrounding the state capital.

The utility, known as SMUD, started SolarShares, one of the nation’s first community solar-power-plant programs, in July 2008 when it offered customers the opportunity to buy electricity from a 1.2-megawatt photovoltaic power plant built on a turkey farm southeast of Sacramento.

“People love solar, but we required you to own a roof” and that it face a certain way, said Mr. Burke. “Multifamily buildings were usually excluded and renters were excluded.”

Then there was the tree issue.

“SMUD has planted hundreds of thousands of trees to shade rooftops and then with solar we’re saying cut them down,” he noted.

The SolarShares program gives customers the option of buying power from a half-kilowatt or a one-kilowatt portion of the solar farm. For instance, for a household that uses 2,158 kilowatt-hours a year, a one-kilowatt solar system would cover about 81 percent of their electricity consumption and cost $21.50 a month. However, the household would receive a monthly credit for the solar electricity produced that would average $13.96.

The pilot SolarShares program sold out within six months and there’s now a waiting list, according to Mr. Burke.

He said SMUD was planning a one-megawatt community solar-power plant that would be built next year and was exploring the placement of up to four megawatts of solar farms on highway rights-of-way owned by the state transportation agency.

Like a community solar farm in St. George, Utah, and a proposed solar garden in Falmouth, Mass., the CleanPath project in Davis would offer residents the chance to buy a physical part of a solar farm.

You can read the rest of the story here.

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