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Avista considers concentrated solar – NW Current

July 31, 2007

Avista considers concentrated solar

When most people think of Northwest energy sources, hydropower is at the top of the list. But Bob Cart, CEO of GreenVolts Inc., a San Francisco-based designer and developer of high concentration photovoltaic systems, thinks about the untapped solar resource in much of eastern Washington, eastern Oregon and Idaho.

Cart — a Bay Area entrepreneur and solar industry “hobbyist” — has raised $1.5 million in seed money, including funds from in-kind services and his cash winnings from the renewable energy prize at the 2006 California Clean Tech Open. GreenVolts recently received an investment of an undisclosed amount from Spokane, Wash.-based utility Avista Corp., which is working with GreenVolts to build a demonstration solar power plant in Rathdrum, Idaho.

“It’s an R&D type of project,” Cart says. “Our goal is not to deliver a certain amount of capacity, but to really understand and characterize the technology.”

Avista’s new integrated resource plan, which is due to be released in August, calls for an increase in renewables, according to company spokesman Hugh Imhof. The Rathdrum test site is close to a substation and has room for five other projects, Imhof says.

“We’re very impressed with their technology and their business plan,” Imhof says. “They seem to really have their act together, and the technology looks like it has the potential to be viable.”

Cart says concentrated solar power systems are practical — even in the Northwest — for a number of reasons. Concentrated solar systems create high outputs of energy by using mirrors to concentrate sunlight onto a super-efficient solar cell. “You get the low cost of a mirror delivering the light on a very efficient cell,” he says. “And you end up using less than one-thousandth of the active solar cell material than you would on a conventional solar panel.”

A typical commercial solar cell has an efficiency of 15 percent, meaning about one-sixth of the sunlight striking the cell generates electricity, according to the National Renewable Energy Laboratory. Low efficiencies require larger arrays of solar panels, which increase costs. By replacing expensive silicon semiconductor materials with simple mirrors, concentrated solar systems further reduce the cost of energy. Concentrated solar systems also achieve much more energy per unit land area, Cart says, claiming that Greenvolts’ technology produces at least twice the energy per unit of land area as do other solar technologies.

GreenVolts’ patent-pending technology uses mirrors licensed from Lawrence Livermore National Laboratory and a super-efficient solar cell made by Boeing subsidiary Spectrolab. Its technology is not to be confused with concentrated solar thermal technology, in which the device that converts the sunlight into electricity is done so thermally rather than through photovoltaics.

Jim Maskrey, vice president of business development and sales for Sopogy Inc., a Hawaii-based manufacturer of concentrating solar thermal power systems, is managing a handful of demonstration projects in Hawaii. The company is targeting commercial clients with large roofs and tracts of land that have the need for systems in the 200 kw-10MW range. “One of the advantages of concentrated solar thermal is that you are able to store the thermal energy and then generate electricity after hours when the sun is not shining,” he says.

Recent legislation in Oregon and Washington has mandated that privately owned utilities acquire a percentage of electricity from renewable sources. Washington’s renewable portfolio standard (RPS), passed by a ballot initiative in November 2006, requires privately owned utilities to acquire 15 percent of their electricity from renewable resources by 2020 and undertake cost-effective energy conservation. The Oregon legislature recently passed an RPS that requires Oregon’s largest utilities to obtain 25 percent of their electricity from renewable energy sources by 2025. It also extends the life of the Oregon Energy Trust to 2025 and increases the trust’s ability to fund energy conservation.

The legislation has led many utilities to study the potential energy output of concentrated solar systems in the sunniest areas of the Northwest region. Seattle-based Puget Sound Energy announced in June 2006 that it chose San Rafael, Calif.-based EI Solutions to build a 500-kilowatt solar power generating facility adjacent to its Wild Horse wind farm near Ellensburg, Wash. [See “Gone with the wind,” nwcurrent, January 2007]. The $3.7 million Wild Horse solar project will have more than 2,500 photovoltaic solar panels, mounted in two separate locations across five acres, according to the utility.

When completed, the project will be the country’s first large-scale combined solar and wind power plant, and the Northwest’s largest solar power-generating plant.

While the Northwest’s solar resource is not as good as Southern California’s or Nevada’s, it is relatively strong in the summer, when the wind is not spinning the region’s many wind turbines as fast and demand for power in the region is strongest.

“One of the advantages of concentrated solar is, even though it costs more to make the power in Washington, it’s still cheaper than any other solar technology,” Cart says. “And it’s still competitive with other sources of daytime peak, especially when it needs to be renewable.”

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