I took some time looking at my own energy use - not comprehensive, but specifically my electricity usage. I believe cleanly generated electricity will be the energy currency of the future, which is why I'm so determined to buy an electric car. The Tesla is a dream:
http://www.teslamotors.com/
but the Tango is a very real possibility:
http://www.commutercars.com/
So...aside from putting photovoltaic panels on the roof - another goal, I wanted to know how the electricity that came in from the grid was generated.

My electric provider is PSNH in New Hampshire. In going over their website, I was surprised to see how much info was there.
In essence, one way or another, you need to keep a turbine spinning to produce electricity. There are three main ways that current energy suppliers are doing this. First, if you've got a huge amount of constantly running water - think Niagara Falls or other reliable hydro source - you can spin the turbine all day and night. Short of this resource, you need to burn fuel. Then you can either use the expanding gases to spin the turbine, or boil water and spin the turbine with the steam produced. It turns out that 80% of the electricity PSNH produces is through the steam process. And what fuel do they use to boil the water? Again, for PSNH, it's oil, coal, and natural gas. All three result in carbon dioxide and nitrogen oxide emissions. Oil and coal also result in sulfur dioxide and carbon monoxide emissions. And burning coal causes emissions of mercury. Hydro causes none of these emissions, but it's not readily available, it's costly to build a dam or generating facility, and it has environmental implications of its own. Surprisingly, even though we've got Vermont Yankee Nuclear in VT, and Seabrook on the coast, PSNH apparently doesn't get its electricity from nuclear. In searching their site for nuclear, I came across this surprising history page:
http://www.psnh.com/AboutPSNH/History/Decades.asp
Having moved to NH in 1997, I had no idea about its history. Apparently PSNH's earlier efforts with Seabrook led them to filing Chapter 11 and they had a very rocky time of it. Now, lest you think I'm starting to feel sorry for them, fear not. They're a power company, and a lot of what's on their site is pure PR shite. I didn't see anything that mentioned plans to generate electricity through wind or solar. And I think some of the largest capacity renewable energy sources lie just off the coast in the form of waves - search "wave energy" on youtube. It's amazing what they're doing in the UK. But, I did determine that a Net Metering Program is available, so once I get those panels on my roof, I can potentially spin the meter backwards, and offset my energy usage at night by whatever I can produce during the day. Ultimately, I want to be net energy negative. But even neutral would be great. Getting there will require more conservation, self-auditing, and tackling how I heat the home and the water - oil now, but hopefully offset by a geothermal heat pump if the democrats can get some tax breaks in place for that kind of investment.