Now large scale conversion of solar energy is a big subject, to which we will keep returning in future issues. But an unavoidable difficulty common to all approaches is the diluteness of solar energy, i.e., the requirement of large collector areas. The total power radiated by the sun is truly astronomical, but the earth receives only about 1 kW per square meter at sea level (a happy numerical accident and another point in favor of going metric), a little more at higher elevations. Consequently, the collector areas needed to provide the hundreds of thousands of megawatts consumed by large industrialized states turn out to be pretty big (though not as enormous as the areas used to provide the most basic form of energy food).
Typically, a stationary satellite converting solar energy to microwaves for beaming to the earth, a $1 billion project proposed by Dr. Peter Glaser of the Arthur D. Little Company, would use a square of solar cells measuring 5 by 5 miles. The Meinels (husband and wife) of the University of Arizona propose "solar farms" for converting heat to steam and hence to electric power, and estimate a yield of 76 M W per square mile of land, or 5,000 square miles of collectors distributed over 10,000 square miles of land to produce 1 million MW. Solar furnaces, i.e., mirrors atop towers focusing the sun's rays into a conversion facility (steam, MHD, coal gasification, etc.) again run into the collector area problem.
A few hundred square miles for collecting solar energy are fine in the Arizona desert; but presumably they would be hard to come by in the Boston Washington corridor. The collector area problem has therefore lead more and more scientists to look for solar energy in the vast collectors that are already collecting it without government grants: the earth's oceans. That idea is explained in the following item.
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Vol. 1, No. 4
Newsletter: Access to Energy Newsletter Archive Volume: Volume 1 Issue/No.: Vol. 1, No. 4 Date: December 01, 1973 11:38 AM (For actual publication date see newsletter.) Title: Let them grovel
Copyright © 2004 - Access to Energy Newsletter Archive
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