Big Problem, Neat Solution

One person in six lives without regular access to safe drinking water, and more than twice that many lack access to adequate sanitation, according to the United Nations. Water-related diseases kill a child every eight seconds and are responsible for 80 percent of all easily preventable illnesses and deaths in the developing world. These alarming statistics have not escaped Dean Kamen's attention. The entrepreneur and quixotic inventor best known for the heavily hyped (and somewhat disappointing) Segway scooter has been working on what he promises will be a revolutionary new water purifier. Dubbed the Slingshot, Kamen's washing-machine-size device produces 10 gallons of clean water an hour on 500 watts of electricity. It uses heat to distill water—boil it, condense it and recycle the energy. The heat that it uses is captured from a new type of generator that, you guessed it, Kamen invented. NEWSWEEK's Brian Braiker spoke with Kamen about his mission to bring light and water to the world's poorest. Excerpts:

NEWSWEEK: You've been working on this for a few years. What's new now?
Dean Kamen: In a perfect world I'd say we're still probably a year away from being able to make reasonable quantities for testing and probably two years away for very high-volume production that will meet the needs of the world. We have been slowly but steadily improving it, making it simpler, cheaper, more reliable, able to deal with more and more different kinds of problematic kinds of water. We get more confident that we really have a neat little solution to a very big problem.

We're talking about two machines that work together, correct?
If you have a source of electricity, you only need one machine: the water machine. Of the billion-plus people on the planet who have no access to clean water and the billion-plus people who have no access to electricity, the overlap between those two populations is pretty large. Which means that if you make a water machine that, on the good-news side, doesn't need disposables—it doesn't need chemicals, doesn't need osmosis membranes, doesn't need activated charcoal, it doesn't need consumables—you sit and say, "That's really neat." But when you say that it does need electricity, you'd be wiping out a huge percentage of potential applications.

So one of them is a generator.
Right, so one of them is the Stirling-cycle generator.

Which generates how?
Actually, that's a great story. We have two separate villages, each about 75 kilometers from Dhaka, the capital of Bangladesh. In each place—and these are small villages, but they've never had electricity—we entirely electrified them for just about exactly six months of continuous operation. The only fuel that went into these machines was cow dung. These machines were put in huts. Next to the hut was a pit. People would collect their cow dung, throw it in the pit, cover it with a cloth and just the natural decomposition would create very, very small vapor pressure of methane gas. It was pretty crummy methane gas—it was full of moisture, full of carbon monoxide, which is toxic. But it turns out, for a Stirling engine, it's got an appetite for methane; it's got an appetite for carbon. It even turns the carbon monoxide into carbon dioxide.

The generator runs just by naturally decomposing cow dung?
Yeah. And methane, by the way, is 21 times as bad for the environment as CO₂ is! So we collect the methane right there in the pit, we turn it immediately into heat by making it the fuel for our little Stirling and we clean up the environment—we get rid of the methane—and we make enough electricity for a little village! So we're pretty excited by that.

How many cows does it take to turn on a light bulb?
[Laughs] That's a very good question to which we don't know the answer. The good news is that I'm not sure it matters that much, because they've got lots of other stuff they can use as fuel.

How much does the water purifier and the generator cost?
Therein lies the rub. We have no production tooling on either machine. Right now they cost me hundreds of thousands dollars apiece because they're being custom built, piece by piece, by my engineers. It's like building a Bugatti piece by piece. Once they're tooled up, we have pretty credible quotes. Over the last year we've been working pretty hard at reducing the manufacturing costs and increasing the required reliability. We believe that each machine will be under a couple thousand bucks. We need to develop the business models and the relationships. In some countries it's going to require microfinancing and entrepreneurs; in other countries it'll be [nongovernmental organizations] or governments.