A New Mexico electric utility company has developed a "booster" system for existing power plants that would use acres of mirrors in a field to reflect the sun's heat to a boiler full of water atop a 1,000-foot tower.

The water would turn to steam and run generating turbines.

By adding such a solar energy system to a power plant fueled by natural gas or oil, consumer costs and fuel usage woule be reduced whenever the sun shined.

A proposal to build a demonstration project was submitted to the Energy Research and Development Administration on Wednesday by Public Service Co. of New Mexico and was received "positively" according to George Kaplan of Erda's solar division.

"We were aware they were working on it and encouraged them," Kaplan said. "We feel very positive about this not only because we feel it will work, but it is being done at the initiative of a utility company and they were willing to spend some of their own money."

ERDA itself has been pushing a project to build an electricity generating plant powered entirely by solar energy and is considering proposals on nine different sites for a $100 million experimental station, Kaplan said.

That plant also would work on the "power tower" principle, Kaplan said.

He said the sole physical proof the system will work was a small experiment made successfully in France last summer under ERDA auspices, but there was "no reason to doubt" its practicality.

The New Mexico plan envisions a maximum cost of $30 million to add the solar system to exisitng plants, which cost hundred of millions of dollars to build - in the case of a one-unit nuclear plant, $1 billion.

J. D. Maddox, spokesman for the New Mexico firm and principal developer of the proposal, said the biggest obstacle to success is the cost of solar componetns, primarily helistats - mirros devices that would reflect the sun's rays to the power tower.

Approximately 5,000 of them would be needed for a demonstration project , Maddox said, and with the plant itself they would cover at least 170 acres of land.

While not every existing power plant has a minimum of 170 acres surrounding it, Maddox said his firm had identified about 600 plants in the Southwest alone that could be adapted to what he calsl the "solar hybrid repowering system."

Maddox said the "booster" concept is designed primarily for planst fueled by natural gas and oil because those fuels cost the most and are in short supply.

"There is a point at which using the solar hybrid idea becomes economical," Maddox said, "If coal was in short supply, and we ran out of uranium, the idea would become economical for coal-fueled planst and nuclear-plants as well."

The power tower concept is necessary, the New Mecico firm explained, because the heat must be concentrated to raise the temperature of the water to about 1,000 degrees Fahrenheit as required by steam cycle power plant generators.

The usual solar energy method of collecting heat from the sun and transmitting it to water and then to a storage tank dilutes the sun's energy and produces tempertaures of 200 degrees or less, the firm said.

The height of the tower is governed by the number of heliostats, and therefore the amount of power, needed: the higher the tower the more heliostats it can handle.

Maddox said the project his firm intends to develop with ERDA assistance would use three towers 430 feet high instead of a single 1000-footer, considered the maximum height.

A small test facility to experiment with the power tower concept is being built at Sandia Laboratories in Alburquerque, but the facility will not generate electricity.

The New Mexico firm's proposal calls for an appropriation by ERDA of $800,000 for a year's planning, involving economic and feasibility studies, Maddox said. After that, it would take about 2 1/2 years to build the demonstration facility and test it. It would be about 20 times and size of the model being built by Sandia, Maddox said.

Public Service Co. of New Mexico is one of a handful of electric utility companies with full scale programs for development of soalar energy.

The firm's president, J.D. Geist, said five home were being built to demonstrate various types of solar heating and allow the company "to make specific recommendations to customers based on cost, performance and expected backup energy requirments."