I was reading an article in the NY Times about what one can do to “green” a home that led me to this list. There is always something else to learn: unofficial list of energy saving tips.
FYI, PEPCO Energy Services does offer “green” and “wind” electricity. Not perfect, but better than regular PEPCO. I think there are some other alternatives in Maryland. I have not investigated recently in the District, but switched to the “green” electricity a number of years ago.