>> Monday, September 14, 2009
Marilynne asked: Solar. Our inverter for our solar panels says we have not contributed 600 pounds of carbon to the environment in the few weeks we've had it. Where does this carbon come from? Power plants or something else?
Presumably, your inverter has calculated the power you've used via the solar panels and there is a standard value assigned as the amount of carbon burned used per kilowatt hour. For instance, my power company (because I use Green Mountain Energy which is 100% renewable energy) says I've saved 855 pounds of carbon last month. Here's the source for their value: U.S.
Environmental Protection Agency, Energy Information Administration, EGRID 2004 database, Texas State Carbon Dioxide Emission Rate of 1.420 lbs of CO2 /kWh.
In theory, this represents how much carbon dioxide would be produced if that same energy were produced by fossil fuels. Chance are your own are is using a similar value in keeping with local norms. I'm not sure if all fossil fuels produce the same amount of carbon per kW, but it's a reasonable estimate.
So this represents the amount of carbon your utility company is not having to produce to provide the power you used. Congratulations!