This morning's opening keynote at ETech was Saul Griffith who ran down the steps he used to calculate his own carbon footprint and then what he had to do to put himself on a "carbon diet." It's not pretty. Doing the calculation is relatively straightforward in terms of the math, but gathering the data isn't easy. I'm hoping that we can get his slides when we put the audio up on IT Conversations because there's some great data there.
Speaking of IT Conversations, a recent IEEE show has a section on home co-generation. You can buy a furnace for your home right now that generates electricity to create the heat. You get power and heat from the same plant, making it much more efficient than buying power separately. You're still burning a hydrocarbon, but you're essentially getting the electricity for (close to) free. Retrofitting an existing home isn't a problem.
On a similar topic, today I put up the latest Technometria show on green computing. The guest is Jeremy Faludi, an expert in green computing. We talk about the carbon footprint of various parts of the computing industry and also mention where computers can help by reducing carbon use.