AMERICA NOT FAR BEHIND

A conceptual design for a 200 MW gas-turbine plant, partly powered by compressed air from underground storage caverns, has recently been completed by General Electric's R&D Center in Schenectady, N.Y. It was developed for a site in the service territory of Alabama Power Co.

And there is an $8 million project to investigate different designs and various sites for the daverns. Three utilities are paying $1 million of their own money, the rest comes from the utility industry's Electric Power Research Institute and ERDA. Potomac Electric will investigate the possibilities of carving caverns out of hard rock in Virginia or Maryland, P.S. of Indiana will study air storage in water-bearing rock, and Middle South Utilities in New Orleans will look into storage caverns in salt domes..

NKW had part of the work ready by using abandoned salt mines as the site for their caverns, which may be part of the reason whyt they figured the investment only 30% higher than for a gas turbine plant. US experts estimate a cost differential of 40%, and a total cost of $250 per installed kW, $50 more than the German figure. The project will run for 18 months before a final decision is made whether to follow the Sherman example. But US utilities often tend to be conservative, and when three of them chip in $1 million of their own money, they mean business.

Unlike the energy contained in fossils, nuclear fuel or elevated water, electric energy cannot (yet) be stored in large quantities. The usual way of converting it to some other energy during the night in order to tap it during peak demand is pumped storage: Water is dumped electrically into an elevated reservoir during off-peak hours, and rushes out through hydraulic turbines during the peak hour, when the utility's base capacity could not make it by itself. The prime example is the giant plant near Ludington, Michigan.

Technically speaking, compressed air storage has some advantages over pumped storage: There are probably more sites available for it, and it is also safer, since it cannot, like (some) dams, cause massive disaster if the stored energy breaks its containment.

But of course, technical considerations must be compromised with dollar costs (or electric wiring would be made of silver, a better conductor than copper). And nowadays dollar costs must be compromised with environmental obstructionism: The invisible hand of a free economy is stayed by the hand of the de-industrializers. It is difficult enough to overcome their opposition in building the pumped storage plant itself (see AtE Sep.77 on New York's Storm King project), but it is getting near impossible to obtain 100 miles of rights of way for the transmission lines, which are being fought not only by legalistic guerilla tactics, but by pseudo-scientific superstitions as well (see editorial).