The French solar power pioneer who was light years ahead

Augustin Mouchot’s solar-powered engine caused a stir at the World Expo in 1878 but it came too soon

In 1861, a French maths teacher, Augustin Mouchot, was so concerned that world supplies of coal would eventually run out that he invented ways of using solar power, starting with a solar water heater for baths and a solar oven for cooking. In 1866, he invented a solar-powered steam engine, using a trough of curved shiny metal to focus the sun’s rays on to a tube filled with water, turning the water to steam, which drove an engine.

Mouchot showed his largest solar engine at the World’s Fair in Paris in 1878. The sun’s rays were concentrated in a reflective metal cone focused on a boiler attached to a heat-powered refrigeration device that produced blocks of ice. It caused a sensation, with audiences watching in amazement to see ice made by solar power. Mouchot also used a solar-powered steam engine to drive a printing press and a water pump for irrigation.

The exhibition in 1878 also marked the rise to prominence of the internal combustion engine, at just the time when coal and oil were becoming much cheaper, and so interest in solar energy and engines rapidly faded. It took more than 100 years before the modern renaissance of solar power.

cover photo:Augustin Mouchot’s solar concentrator, 1878. Illustration: Science History Images/Alamy