BYO Generator -- and Sewage Treatment Plant

Because of my recent obsession with toilets and contaminated water supplies, I wanted to mention one other thing that Steven Johnson brought up in The Ghost Map.

Dean Kamen, the inventor of the Segway, has a more recent invention. It's a pair of machines, each about as big as a dishwasher. One is a generator powered by animal manure, which generates enough electricity to power 70 energy-efficient lightbulbs. The other machine is a water purifier, which is powered -- get this -- by the waste heat from the Stirling generator.

Called Slingshot, the water purifier can clean up any type of water, from sewage on down, and cleans it up by extracting the clean water from vaporization of the original contaminated water. One machine can make a thousand liters a day (about 250 gallons).

Kamen wants to be able to produce the machines for $1,000 to $2,000 each (although each hand-machined prototype now costs $100,000). Iqbal Quadir, a Bangladeshi entrepreneur, has run trials of the generator, and is trying to raise capital to begin production in that country. His vision is to place 500,000 one-kilowatt power plants in villages all over Bangladesh, where their owners could resell the power to neighbors -- rather than building one 500,000 kilowatt power plant in a centralized location.

Somehow, it's not too hard to imagine the Gates Foundation funding a bunch of these.