Solar Power Hype

"Tapping the Sun" (C&EN, Aug. 27, page 16) begins with Nathan Lewis' oft-repeated claim: "More energy—in the form of sunlight—strikes Earth in one hour than all of the energy consumed by humans in an entire year." From this statistic, he concludes that solar power plants can fulfill all of mankind's electrical energy needs—no nuclear reactors, no wind turbines, no hydropower, only solar panels.

This sounds too good to be true, and it is. Broad statements like this ignore essential engineering details. Where would such solar farms be located? We must exclude areas of Earth that are impractical or proscribed for locating solar farms: oceans, croplands, pastures, forestlands, bogs, tundra, mountains, canyons, national parks, and so on. We are left with a few scattered desert areas considered so marginal as to be sacrificed for solar parks.

Even in these regions, sunshine is a dilute energy source. We live more or less comfortably in this "working fluid." As a result, commercial solar power plants cover many square miles and cost billions of dollars.

Finally, solar's intermittency problem has no practical solution. No solar electricity is generated at night, and little is produced in the mornings, in the evenings, or during overcast periods. Even if a practical scheme were developed for storing solar energy to be used in off-peak hours, such a strategy would massively add to the required collector area and commensurately increase the cost of such a plant.

Increasing solar's share from its present global contribution of 0.001% to 100% would require miracles, not technological advances. If you need more convincing, then look at the history of solar energy in California, a state that has enthusiastically embraced this source. Historical data for the past two decades are available on the California Energy Commission website, and they don't bode well for solar even becoming a major player. By the way, if you want to see California's pre-industrialized Mohave Desert, then you better visit soon.

Ed Johnson
Sunnyvale, Calif.