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Solar farm

This 2011 photo shows some of the 30,000 solar panels that make up the Public Service Company of New Mexico's 2-megawatt photovoltaic array in Albuquerque. A developer is looking at two sites in Napa County for a similar facility.

Solar power could be coming to Napa County to feed the power grid with renewable energy, though photovoltaic arrays are unlikely to gobble up vineyards.

Various public and private buildings are already powered by arrays on rooftops and carports and in fields. From Napa Valley College to the Napa Sanitation District plant to schools to private homes, solar panels are a common sight.

Now a developer wants to do something bigger and install solar panels at two local sites to generate power to sell to Marin Clean Energy (MCE). J.R. Killigrew of MCE said the projects combined could generate six megawatts by year’s end.

“It’s the equivalent of powering 2,000 homes,” he said.

MCE provides renewable energy to various Bay Area communities – including Napa County and its cities—using PG&E’s transmission and billing system. If the two local projects come to fruition, Napa County will create renewable energy for MCE.

But where would the two proposed solar farms go in Napa County, where land for development is tight? Killigrew said MCE is bound by confidentiality not to reveal this information or the identity of the developer.

MCE officials said they would give the developer the Napa Valley Register’s contact information. As of Friday, the developer had yet to call. It was unclear if the developer has made a formal application with a local community.

Killigrew did say the arrays would be on private land. It takes five acres to generate a megawatt, he added. That indicates a total of about 30 acres are needed in areas near transmission lines.

The rural county is a possibility for solar farms. Napa County allows electric generation plants in any zoning district with a use permit. But top grapegrowing sites would seem to be out, given land prices and local sentiment.

Solar farms can also be in cities, such as the 10-megawatt MCE Solar One farm at the Chevron refinery in Richmond. They can be on the rooftops of airports, such as at San Rafael Airport.

But whether any of this applies to the proposed Napa County project is unknown at this point.

“This is a Bay Area company that’s developing it,” said David Potovsky of MCE. “I heard they plan on hiring locally. It’s land that sounds like it wouldn’t be used for anything.”

The idea of building a Napa County solar farm to generate electricity for the power grid isn’t new. Finding possible places to put one has led to creative thinking.

For example, a closed dump doesn’t have much competition for other uses. The county in 2010 approved having a 6.7 megawatt farm with 25,000 door-sized panels on the old landfill near American Canyon that is owned by the Napa-Vallejo Waste Management Authority.

“We had a tentative deal that didn’t work out for financing reasons,” said Richard Luthy, executive director of the waste management authority. “Since that time, the board has decided to take a little time to see how the solar market is playing out.”

Installing a solar array on top of a landfill is a different proposition from other sites, Luthy said. The landfill settles. It has pipes for collecting methane gas.

The authority recently installed a 55-kilowatt solar system on the landfill to provide power for the landfill flare station. The array, which Luthy said cannot be readily seen from the hiking paths around the landfill, started working late last year.

“It’s kind of an experiment for us,” Luthy said.

So the American Canyon landfill remains a candidate for a commercial solar project, with nothing apparently on the horizon.

A wastewater retention pond is another place that doesn’t have development competition. The Napa Sanitation District has a mile- by half-mile system of ponds near the airport industrial area.

Last year, the Napa Sanitation District Board of Directors held a closed session to discuss a possible deal with a company that specializes in floating solar farms. It took no action.

Another site mentioned as a solar power candidate is the former Homestake Mine in the remote mountains of eastern Napa County. The gold mine closed in 2002 and is now part of the University of California’s Natural Reserve System.

A 2015 MCE document said the Homestake Mine could have a large-scale Napa County project – 125 megawatts, enough to power 40,000 homes.

“I think that’s the Holy Grail because it’s an enormous size,” Potovsky said. “Once you get to that site, you can really build an affordable project.”

County Supervisor Brad Wagenknecht represents Napa County on the MCE Board of Directors. He sees possibilities for Napa County to contribute renewable solar energy to the grid.

“If you have some other value for the land, you’re probably going to use it for some other value,” Wagenknecht said. “But if you have some piece of land that isn’t valuable and it’s not going to produce anything for you, solar can be an answer.”

If someone has a large rooftop area that isn’t bringing in any money, they can put solar on it, he said.

“Why not?” Wagenknecht said.

MCE has its “feed-in tariff” program to encourage solar projects. The program provides predictable energy prices for small-scale renewable energy developers over a 20-year contract.

Those solar farm projects that MCE officials mentioned at the unidentified, two Napa County sites would be under the feed-in tariff program.

“We’re very happy there are some projects coming to Napa,” Potovsky said. “We’ve done a significant number of projects in Marin and Contra Costa counties. We haven’t done anything in Napa County.”


Napa County Reporter

Barry Eberling covers Napa County government, transportation, the environment and general assignments. He was worked for the Napa Valley Register since fall 2014 and previously worked 27 years for the Daily Republic of Fairfield. He is a graduate of UC Sa