Thanks to Digg
I found this article
from The Christian Science Monitor
. It's about a local Massachusetts company, Climate Energy
, that sells micro-combined heat and power systems for homes and small businesses.
Micro-combined heat and power, or cogeneration, is pretty much exactly what it sounds like: a system that provides both heat and power. The way it works is so incredibly simple and obvious that most of us have probably actually thought of it a few times. Basically, it's just an internal combustion electric generator (it burns natural gas, rather than gasoline or oil). As anyone who drives a car knows, internal combustion engines put off quite a lot of 'waste heat'. So in a Micro-CHP system, that heat is put to use instead, heating your home. The result is that you heat your house and generate electricity at the same time. Because the 'waste heat' is no longer wasted, the system can actually approach 90% efficiency, making it an extremely economical use of resources.
The system costs around $20,000 but will apparently pay for itself within 3-7 years (depending on local energy costs). The currently available model heats air for use in forced air heating systems, but they're working on a model that will heat water for other heating systems as well. I assume it would also be possible to use one to either replace or augment your water heater to increase efficiency and power generation (and therefore savings and potentially even earnings) further. Combine a system like this with photo-voltaic solar generation on your roof and you're probably getting pretty close to living off the grid.
As a soon-to-be homeowner (hopefully), this is a very interesting piece of technology to me.