Empire Off The Grid

Electricity From Cow Flops

The Stirling engine has been around for 193 years, but the reason it is not part of your everyday energy vocabulary is that it is only 20 percent efficient at converting burned fuel to electricity. That’s far too low for developed countries. But in the developing world, where about a quarter of the world’s people live, it might be good enough. In many of those places, people are still burning wood and kerosene to cook their food and light their homes. 

Dean Kamen revisited the Stirling engine—not to make it more efficient but to make it sturdier. He and his engineers at Deka revamped the engine to make it maintenance-free.

Last year, Kamen teamed up with Bangladeshi cellphone mogul Iqbal Quadir to bring power to places that had never had it. For six months, prototypes of Kamen’s reconceived Stirling engine powered three villages in Bangladesh. What particularly suits the Stirling for the developing world is that it can burn any liquid or gas fuel, and unlike other engines, it can tolerate fuel with impurities. Most generators can’t do much with carbon-dioxide-infused methane released by decomposing cow manure, but the Stirling is happy with it.

Villagers shoveled cow dung into a pit, over which a dome collected the methane, carbon dioxide, and other effluent that seeped out of the waste. They then diverted the useful parts into the Stirling, which burned the fumes as fuel and generated energy. People came to the engine once a day to charge the batteries in their LED lanterns. 

The ripple effects of the Stirling went far beyond merely providing light. One intended and much-hoped-for consequence was the spike in the villages’ literacy rates. Because the villagers now had access to artificial light, they were able to study at night independent of their circadian rhythms. Other consequences, unintended but welcome, included reduced contamination, as cow dung was now meticulously collected as a commodity instead of being left out to contaminate the village’s water supply. And then there was the free market. “Three companies sprang up around the Stirling,” Kamen says. “One guy was making money shoveling the cow manure into the pit. Another guy was making money taking care of the machine. The third guy was selling the lamps.” And all because of cow dung. “Now things we used to consider waste are developing value as we become more evolved and energy becomes more expensive,” Kamen explains to visitors to North Dumpling Island.

Lighting technologist Fritz Morgan, Kamen’s chief collaborator, says that North Dumpling is working toward a similar goal. “Eventually, we’ll convert all the island’s biomass—grass clippings and, of course, human refuse—and use the methane from those components to run the Stirling engine.”

He is met by blank stares from the visitors. “We’ll take the human by-product—the, uh, human biomass,” he elaborates, “and use it to power the Stirling engine.”

Everyone still looks puzzled.

Morgan lets out a resigned sigh. “We’re going to take your s**t and burn it!”