Charles C. Mann Quote
But Mouchot was learning the limitations of solar power. Sunlight is plentiful and free, but it comes as an intermittent flow, not a reliable stock. Mouchot’s engines were useless at night or on cloudy days—and French skies were often cloudy. Even when the sun shone, the mirrors were costly. One skeptical engineer noted in a review of Mouchot’s work that running a typical one-horsepower steam engine required about two kilograms [4.4 pounds] of coal. To drive the same engine with the sun, Mouchot would need a mirror of about 320 square feet. Operating factory-scale machinery would require hundreds of giant mirrors—a huge expense. Meanwhile, French industry was not running out of fuel, as so many had predicted it would. Paris had signed a trade agreement with London, and the nation was awash with British coal.
But Mouchot was learning the limitations of solar power. Sunlight is plentiful and free, but it comes as an intermittent flow, not a reliable stock. Mouchot’s engines were useless at night or on cloudy days—and French skies were often cloudy. Even when the sun shone, the mirrors were costly. One skeptical engineer noted in a review of Mouchot’s work that running a typical one-horsepower steam engine required about two kilograms [4.4 pounds] of coal. To drive the same engine with the sun, Mouchot would need a mirror of about 320 square feet. Operating factory-scale machinery would require hundreds of giant mirrors—a huge expense. Meanwhile, French industry was not running out of fuel, as so many had predicted it would. Paris had signed a trade agreement with London, and the nation was awash with British coal.