Gas turbines powered much of 20th-century technology, from commercial and military aircraft to the large gas-fired plants that helped supply U.S. electricity. But these days it isn’t the hulking machines in the lab’s museum that capture Epstein’s enthusiasm. Instead it’s a jet engine shrunk to about the size of a coat button that sits on the corner of his desk.

It’s a Lilliputian version of the multiton jet engines that changed air travel, and, he believes, it could be key to powering 21st-century technology.



Though the turbine’s blades span an area smaller than a dime, they spin at more than a million revolutions per minute and are designed to produce enough electricity to power handheld electronics. In the foreseeable future, Epstein expects, his tiny turbines will serve as a battery replacement, first for soldiers and then for consumers. But he has an even more ambitious vision: that small clusters of the engines could serve as home generating plants, freeing consumers from the power grid, with its occasional black- and brownouts. The technology could be especially useful in poor countries and remote areas that lack extensive and reliable grids for distributing electricity. A comparison to how the continuous shrinkage of the integrated circuit drove the microelectronic revolution is tempting. “Just as PCs pushed the computing infrastructure out to users, microengines could push the energy infrastructure of society out to users,” says Epstein.



Epstein’s immediate goal, however, is to use these miniature engines as a cheap and efficient alternative to batteries for cell phones, digital cameras, PDAs, laptop computers, and other portable electronic devices. The motivation is simple: batteries are heavy and expensive and require frequent recharging. And they don’t produce much electricity, for all their size and weight.



The consequences of these failings go beyond consumer inconvenience. Today’s soldiers are often forced to lug around brick-sized batteries to power their high-tech gear. And hamstrung by short-lived power supplies, designers of next-generation electronics are frequently forced to leave out energy-hungry improvements and features like bigger, brighter screens and more powerful processors. Take, for example, the “ultimate PDA” from Frog Design, a Sunnyvale, CA–based firm specializing in industrial design. The device combines multiple cell-phone and Wi-Fi radio protocols, GPS location, a projection screen, the functionality of a laptop, and the ability to browse through video libraries and play full-length movies. But it exists only as a mock-up; it would drain any reasonably sized battery in half an hour. With functions like GPS location and radio communications, “you’re just eating through batteries,” says Valerie Casey at Frog Design.



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