So . . . the Bloom Box.
I am not yet up to the point of Cautiously Optimistic about it, myself. I am ready to be convinced one way or the other, although I don't expect to reach a conclusion anytime too soon.
Basically, it seems to be . . . a fuel cell. Now, fuel cells are a good idea. At the end of the day, a fuel cell is essentially a generator that perfectly burns the fuel you put in. The pollution that results from burning coal or gasoline comes from two sources: contaminants that are in the fuel and imperfect combustion of the fuel. If you burned chemically pure gasoline at an optimum temperature (hotter than a typical car engine), you'd get hot water and carbon dioxide and not much of anything else in the exhaust. Run that gasoline through a fuel cell, and you get the exact same waste out. It's pretty much only with pure-hydrogen fuel cells that you get no CO2.
Fuel cells have the potential to run cooler than combustion engines, more quietly, more efficiently, and with less maintenance. They don't always do these things, though, and they generally currently cost a lot more up front.
The Bloom Box is said to be able to run on almost anything, but I've only heard about it being set up to run on relatively clean gasses, usually natural gas. Running one on gasoline, say, would take a rather different setup, and you'd have some nasty waste products gunking the thing up. Still, not impossible.
The main problem I have with the Bloom Box is that 95% of their PR seems to be just PR. Some big companies are already using the things, but using the thing is great PR, too. These suckers currently cost a fortune, and although they say they'll get the price down, they're very fuzzy about it. For instance, how long would a Box last in an average home? If it costs $3000 and saves you $300 a year but lasts five years, that's not so great. I'm told they run at a rather high temperature -- probably too hot to use in a car, for instance. That's hot.
Several years ago (ten, even?), there was a company out the Portland / Seattle way putting $5000 fuel cell machines in people's homes. Those were the size of water heaters, and they ran on natural gas. They provided heat, electicity, and hot water all out of one cogeneration machine, and they were supposed to last at least ten years. A Bloom Box for the home is supposed to be much smaller, although also not cogenerating, and slightly cheaper, but they're saying it won't be ready for 5-10 years. I'm not sure that's that much of a breakthrough.
I'm also not sure how the price of natural gas would fluctuate if these things became popular. Biogas is a nice idea, but unless you run a hog or dairy farm there may very well not be enough of the stuff to go around.
Call me crazy, but those new whole-house battery systems are a LOT more exciting to me. Not only do they make solar and wind power much much more useful and attractive, but they mean everyone could buy electricity during cheaper non-peak hours. And that the power companies never needed to use peak hours again, which would make new power plants and maintaining old ones vastly cheaper. And it would be like upgrading the power grid, since average power flow would drop and even out.
So I have nothing against the Bloom Box, assuming it's as-advertised, but it doesn't sound like anything like the big deal they've been making it out to be. Maybe if they can get the price down. It would actually be awesome in many ways if people could cheaply and cleanly generate so much electricity at home that they could switch to electric heat, for instance.