When Superstorm Sandy hit eastern Long Island in October 2012, virtually every resident of East Hampton lost power for days, some for weeks. Town leaders knew they couldn't let it happen again; they needed to find a way to protect their community and make it more resilient in the future. "It was a wake-up call for everybody who lives on the East Coast, certainly in our community out here on the eastern end of Long Island," said East Hampton town supervisor Larry Cantwell. So, the town acted quickly to adopt an ambitious goal: converting 100 percent of its electrical energy to renewable sources by 2020. Its plan includes solar and wind energy, and it's exploring creating one of New York's first microgrids as a backup power source for emergency facilities. "Every household, every business, it's going to require that we think differently about traditional power sources and that we reject traditional fuel sources," said Cantwell. "It's going to take every citizen accepting responsibility for becoming more energy efficient." Switching to renewables is a growing trend among towns, cities and states in the U.S. But while most are aiming to be 20 percent, 30 percent or 50 percent renewable by a given date, East Hampton is one of a handful of municipalities going all-in.



This solar array is the size of 11 football fields and is in the heart of a residential neighborhood in San Francisco. Jodi Grainick | CNBC

Aspen, Colorado; Burlington, Vermont; and Greensburg, Kansas, have already proven it can be done. But, like East Hampton, which has 20,000 residents, those are all relatively small towns.

Some much bigger cities have also taken up the challenge, including San Diego (with a goal to convert by 2035), Honolulu (by 2045) and San Francisco (by 2030). "We know that we are in a national city, a popular city, but we also want to be a city that contributes to the challenges of climate change and improves our world," said San Francisco Mayor Ed Lee. "If we can do that here, I suggest that we can do that anywhere." The city adopted its 100 percent goal in 2011, but had already been working to reduce greenhouse gas emissions since issuing its electricity resource plan in 2002. It has since closed two GHG-emitting power plants and expanded its use of the Hetch Hetchy Hydroelectric Power System to now supply 17 percent of city's electricity needs.

A number of solar arrays were built, including one on the roof of the historic City Hall. The 5-megawatt Sunset Reservoir solar array in the middle of the city is the size of 11 football fields and has 24,000 solar panels, and will eventually be expanded.

Outside the city, San Francisco is building a large wind farm. Meanwhile, every city building, including City Hall, libraries, police and fire stations and the airport are already using 100 percent GHG-free energy. Twenty-three percent of the city's electric supplies are now from the renewable sources of wind, solar, geothermal and biogas, with another 21 percent being GHG-free hydroelectric. The focus is now on getting more residents and private businesses on board. A new 15,000 resident development at Hunter's Point will be the first in the city to be 100 percent GHG-free. The city just launched CleanPowerSF, a community choice clean energy aggregation program. Through utility company PSE&G residents are automatically enrolled to get some of their electricity from renewable sources at the same price they've been paying. But they can also opt into 100 percent renewable for a little higher price.



Mayor Edwin M. Lee, of San Francisco, California Jodi Grainick | CNBC

"That participation means we're actually paying our local public utilities commission to source my energy in the right way," said Lee. "And then I'll add to that by putting a solar array on to my rooftop, and hopefully contribute through the credit program, other solar array programs, where we'll actually help build the industry by our own contribution."

"That will help defray all of these upfront costs of getting the program started and then with people getting hired and locally programmed," he said. "I think that that will also add to the entire value of this cost. We'll bring every dollar that we're spending on the upfront into a cost-neutral basis and have that whole system paid for."



It's going to take time to make the progress we want. We don't just turn on a light switch. Larry Cantwell East Hampton town supervisor

Lee expects these programs to create almost 10,000 jobs. Some analysts expect the trend towards more renewable energy to continue despite the relatively low cost of oil. "I think the oil correlation as it's historically been is a bygone," said Julien Dumoulin-Smith, an analyst covering power, utilities and renewables at UBS. "When it comes to the renewables industry, the prospects over the near-term, medium-term and long-term arguably have never been better. The technology costs continue to trend lower. A lot of these towns are opting to sign up for 100 percent renewables on the back of tax credits. You see a lot of incentives out there to basically step up. It doesn't cost you meaningfully more to do it, so why not take the plunge?" But going 100 percent renewable isn't without its challenges. Lee said the biggest obstacle in San Francisco is making sure in such a dense city with such a diverse population, that everyone is included and participating.