My vision would be to use turbines and solar panels where it's practical to offset the costs of powering a federal building. A potential "selling" of extra energy back to the power companies could potentially help the Government to make some money.
The second part of this suggestion is to buy "plug-in" electric cars like a Chevy Volt. No fuel usage if you have a charging station on your building. And if the power is derived from a renewable energy source then you have free fuel for travel.