Google's Project Sunroof uses Google Maps information to measure the size of a house's roof and the amount of sunlight it receive yearly to calculate the annual value of the electricity which solar panels of that roof would provide. And they can also connect you with local businesses who install solar panels. Right now Project Sunroof is brand-new and it only covers the San Francisco area, Fresno and Boston, but Google has plans to expand its coverage. Here is an article on Project Sunroof from Wired, and here is one from TNW News.
Here is a great article from the Nation which goes into some depth about the economics and politics of oil, coal, gas, wind, solar and other sources of energy. A key sentence from that article:
"Solar and wind are technologies and not fuels, and as such they typically become cheaper with scale and time."
Think about computers and smart phones: the materials used to make them, including various metals, have become more expensive over the past 30 years. But what's happened to the prices of computers made of those materials? That's right. Oil, coal and gas are materials, like those metals and other materials, are only going to continue to get more expensive. Solar and wind energy are technologies. Wake up and smell the 21st century. If we can stop oil companies from continuing to sabotage alternative energies and misinform the public about them, the 21st century just might smell a lot better than the 20th.