Is solar energy the answer to Imperial Valley's peak energy needs in the future?

March 15, 2001|By RUDY YNIGUEZ, Staff Writer

The sun provides more than enough heat in the Imperial Valley summer to require the use of air conditioning.

Now the sun is being looked at as a means of providing the energy to generate the electricity that could power those same cooling needs, as well as others.

A proposal by King of Prussia, Pa.-based Princeton Energy Systems is to study how the sun — through the use of photovoltaic cells — might be used to provide power during peak production periods, reduce the amount of electricity needed from the power grid during peak production periods and provide an extended life for building roof areas by protecting the roof from the sun.

The projects proposed to be studied include the under-construction beef plant in Brawley, a generic warehouse in the Gateway of the Americas project and the Brawley Union High School, according to David J. Smith, PES managing director, who's made several presentations of a photovoltaic system to Imperial Irrigation District staff, BUHS staff and representatives of Gateway landowners.


Smith said besides being a nonpolluting source of electricity, a photovoltaic system provides a hedge against future increases in the cost of power including for businesses that self-generate; that the system is modular and can be changed to suit changing needs; and that the system has a lifespan of more than 20 years.

Smith proposes the use of a photovoltaic system known as PowerGuard for the three projects. PowerGuard is a light-weight system consisting of the photovoltaic cells, 0.1 inch in thickness and 3.5 feet by 4 feet, mounted on a 0.75 inch heat sink mount on 2 inch thick insulation. The modules would be interlocked and placed on the buildings' roofs. There is no need to permanently anchor the modules and the modules are designed to exert downward pressure when the wind blows.

The downward pressure and the weight of the modules do not require that roofs be reinforced, Smith said.

This is how the process works: Sunlight strikes silicon in the photovoltaic cells; electrons in the silicon are released; the electrons — having negative electrical charges — are attracted to a positively charged grid of wires; the various current flows are gathered, converted to alternating current from direct current and supplied to the building's distribution system.

The amount of photovoltaic power being generated — which depends on the amount of sunshine — determines how much power will be drawn from the regular power grid; in this case the Imperial Irrigation District.

Besides studying the potential benefits to the buildings, the study will investigate sources of financing.

Smith said the cost can range from $5 to $6.50 per watt of electricity, and as high as $8 per watt. A current estimate would have the beef plant's photovoltaic system generate about 1.5 million watts.

"There lies some of the hurdles," Smith said. "It's not inexpensive."

One of those who was presented the information was BUHS district engineer Jimmy Sanders Jr., who said any decision about the use of such a system lies with the BUHS Board of Trustees.

He also said the presentation he attended Tuesday omitted a discussion of costs, and that without that he could not make any recommendations to the trustees.

"The idea sounded good," Sanders said Wednesday.

Representatives of the beef plant who attended similar presentations on the system could not be reached for comment.

Speaking for two Gateway landowners, Tom DuBose, manager of El Centro-based Development Design & Engineering LLC, said the landowners are interested in the study. DuBose will help PES in gathering data for the study.

The photovoltaic system is not without potential shortcomings, however.

Smith said when ambient temperatures exceed 110 degrees the system's efficiency decreases by about 5 to 10 percent, depending on the system's manufacturer. He said the effects of dusty conditions are so small as to be immeasurable.

At its Feb. 27 meeting, the county Board of Supervisors voted to pay for half the study's costs, $25,000. The IID Board of Directors will be asked for the other half at its next meeting.

Staff Writer Rudy Yniguez can be reached at 337-3440.

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