If the US were to tap into their renewable energy resources we could keep our cities running on the
"The United States is buffeted each year by 4,000 terawatts of solar power, 1,800 terawatts of wind power, 1,170 terawatts of wave power, and 17 terawatts of tidal power—far more than the 3.9 terawatts of electricity that the country uses annually. If we were to tap a small fraction of that power, the elements could keep our cities running forever."
Farris, David. September 2013. Electrify the Elements. Sierra. http://www.sierraclub.org/sierra/2013-5-september-october/feature/electr...