While San Francisco is most famously known for its cable cars, the Golden Gate Bridge and progressive politics, within the next decade it will also be recognized as the greenest city in the country.

On Feb. 1, the San Francisco Board of Supervisors approved the spending of a $250,000 grant by the Department of the Environment on research to create ways to obtain 100 percent of its power demand solely from renewable energy sources by 2020.

Currently, the city depends heavily on the Pacific Gas & Electric Company and the Hetch Hetchy reservoir to provide the city’s 950-megawatt peak power demand, said Department of Energy spokesman Mark Westlund. If the development of a plan is successful, solar, wind and hydropower would supply the city’s entire electric demand.

“No other (Bay Area) city has established such ambitious goal,” Westlund said.

The idea to generate all of San Francisco’s power from renewable resources was announced in December 2010 when, at a speech at the completion of the Sunset Reservoir Solar Project, former Mayor Gavin Newsom said the city had to decrease its dependence on fossil fuels by 2020 in order to achieve a national 20 percent reduction of greenhouse gases.

The grant for the city’s planning work was provided by the Sidney E. Frank Foundation, which, according to its website, has a duty of giving away $20 million annually to medical research, art, environmental and Israeli educational projects. The foundation has contributed money to the city for the creation of clean energy projects for the past five years, Westlund said.

Johanna Partin, former environmental policy adviser to Newsom, told the New York Times last December that one day, San Francisco will have anywhere from 30 to 100 MW of wave-derived energy available.

Natural resources mean energy efficiency, but with limitations. According to the U.S. Energy Information Administration’s website, the dependence on renewable sources is not always reliable due to weather variables. Cloudy days reduce solar power, calm days reduce wind power, and droughts reduce the water available for hydropower.

Westlund said finding a solution to the impact that weather conditions pose to renewable sources was part of the plan.

The government’s website further said renewable energy is generally more expensive to produce and use than fossil fuels because of the construction of power lines to cities.

“The conversion will certainly impose costs in the short run, but the longterm benefit is a sustainable system,” said Sheldon Gen, assistant professor of environmental studies at SF State. “We don’t get that with non-renewable energy sources.”