A BLUSHING MEGAWATT OF SOLAR POWER

On the other hand, it lavishly funds research of new energy sources: There never was any French gas or oil, and coal is running out.

France has the world's only major tidal plant (AtE June 76); it has the world's largest breeder reactor in commercial operation and is about to begin construction of a breeder five times as large; it is hoping for 70% nuclear capacity by 1985, which would make it the world's most nuclear country (now Switzerland with 18%).

France also has the world's largest solar facility, a 1 MW solar furnace at Odeillo in the Pyrenees. It consists of 63 rectangular flat mirrors, each about 25 by 20 ft and composed of 180 smaller mirrors. They automatically track the sun and reflect its rays into a fixed parabolic mirror, which is itself made up of 9,000 small mirrors. These again focus the rays into the receiver, a boiler producing steam at 270 degreesC to run turbogenerators with up to 1 MW electrical output - when the sun is out.

The 63 large flat mirrors are arranged in 8 terraces on a mountain slope and are staggered with slight overlaps in elevation and sideways, so as to present the incoming sunlight with a continuous, gapless area in projection (or, on the contrary, to reduce the flow of solar power to the receiver). The project is, no doubt, very useful for research purposes. But once more, the diluteness of solar power is reflected (so to speak) in the area of the costly mirrors. The costs of the project must be in the hundreds of millions; and the result is a lonely, blushing megawatt.

The efficient way for large-scale solar energy conversion is to harness the solar power that is already being tapped by nature. The most obvious way is OTEC (AtE Feb.77); but another project is now under consideration in Israel.

The level of the Dead Sea lies some 1,300 ft below the level of the Mediterranean. If a 120-mile tunnel were dug under the Judean Mountains to connect the two, the Dead Sea would not "fill up;" the water would be evaporated by the sun. The continuous water flow through a slightly inclined tunnel, and then through a near- vertical penstock could power a hydroelectric plant. (All hydroplants are ultimately run by the sun, which puts the water back behind the dam.)

And the megawatts no longer blush - there would be 300 of them.