PHOTO CREDIT: SOLAR HOME & BUSINESS JOURNAL
Wind turbines near Palm Springs, Calif.,
not far from a site where a 13-megawatt
solar power plant is proposed.

Published June 12, 2010

A planned solar photovoltaic power plant in the retirement haven of Palm Springs, Calif., would break new ground in the United States by locating the modules among towering wind turbines.

The Palm Springs area is home to vast forests of turbines numbering in the thousands that spin in the winds that stream through a pass between two high mountain ranges and flow off neighboring foothills in the afternoons and evenings.

A 13-megawatt solar PV power plant called the Mountain View Solar Project is proposed on a 77-acre site just south of Interstate 10 that now contains 10 wind turbines. It would be the first large-scale solar project in Palm Springs.

"What's interesting about this renewable power project in particular is the non-coincidental nature of the two sources of power," said Nathan Potter, a representative of the developer, AES Solar Energy of Arlington, Va., at a June 9 meeting of the Palm Springs Planning Commission. "The wind is generally strongest during the evening, and obviously the sun during the day."

The photovoltaic modules are to be installed among a collection of wind turbines owned by AES Wind Generation, a sister company of AES Solar Energy. Both are part of AES Corp.

Mr. Potter said he is not aware of any installation in the world that combines large-scale solar and wind generation at the same site.

"This could be the proving ground for a mixture of renewable energies that could be implemented not only here in the state but in other parts of the world where these two resources overlap," he said.

The project site is adjacent to high-voltage transmission lines and an electrical substation called Mountain View that is owned by Southern California Edison Co.

"What we're doing is to plan on putting solar panels on otherwise useless land," Mr. Potter told the commission, noting that the presence of the existing electricity system means the project "will forgo the need of further build-out of energy infrastructure."

In addition to serving as a "test case" for combining the two renewable-energy sources, the project is an example of "how to do more with less," he added.

The solar modules are to be installed on a graded site below and among the turbines. The ground will be covered in gravel for control of dust and erosion.

Shading from the turbine towers and blades will reduce the output somewhat from the solar array, the commission was told.

The Planning Commission approved the project by a 6-0 vote of the members present, although several questions were raised. One commission member asked whether there could be a risk of fire if a blade fell off a turbine onto the array. Mr. Potter said the modules do not contain significant amounts of combustible materials and most of the wiring would be underground.

Two commission members expressed concerns about the grading and the use of gravel and asked whether the natural contours of the land and the existing vegetation could be retained, and whether the modules would have to be installed in precise rows.

Mr. Potter and other AES Solar representatives said the array had to be designed so that panels would not shade one another and could be economically congregated, and that grading also would permit the installation of concrete footings to secure the racks. Most of the vegetation under the modules and racks would have to be removed or disturbed during construction, the commission was told. The extent to which the desert plants would regrow under the panels' shade is uncertain, and dust-control measures would still have to be used.

The project still awaits approval by state officials.

Although the 13-megawatt Mountain View Solar Project would be the first utility-scale solar plant in Palm Springs, the country's second-largest solar PV power plant, a 21-megawatt installation, is located on the outskirts of Blythe, Calif., across the Colorado Desert about 120 miles east of the city.

About 10 very-large-scale solar projects are in the planning or development stages along Interstate 10 and nearby areas between Palm Springs and Blythe, ranging up to 550 megawatts of production capacity for one solar PV plant and up to 986 mw for a solar thermal plant.