By 2020, the city and county of San Francisco is planning to be 100 percent powered by green energy. Talk about a highly ambitious energy plan.

Then-mayor Gavin Newsom made this startling announcement in early December at the launch of the Sunset Reservoir, a 24,000-panel solar array that more than triples the amount of solar electricity the city produces. The new array is on line and generating up to 5 megawatts (MW) of clean energy per day, increasing San Francisco’s municipal solar generating capacity from 2 MW to more than 7 MW.

At the Sunset Reservoir launch, Newsom announced a $250,000 grant awarded by the Sidney Frank Foundation to San Francisco to develop an implementation plan over the next 12 months to generate 100 percent of the city’s electricity from renewable sources by 2020 in support of its carbon-neutrality goal. Newsom created a task force to advise the city on how best to achieve this goal.

“San Francisco has the audacious goal of reducing its greenhouse gases to 20 percent below 1990 levels, and to reach this goal, we need to continue reducing our dependence on fossil fuels and power the entire city, not just municipal operations, on 100 percent renewable electricity,” he said. “We have come a long way towards creating a brighter energy future for San Francisco. Now we must lead the way towards a city powered entirely by energy that produces no greenhouse gases, and we must challenge ourselves to achieve it within 10 years.”

One major component of the plan was a commitment from the California Independent System Operator to close the Potrero Power Plant, the only remaining fossil-fueled power plant within San Francisco. It provides approximately one-third of the city’s peak electrical power and is scheduled to cease operations this year.

“After years of work, we have finally obtained the long-sought commitment from state energy regulators that will allow us to close the old, polluting Potrero Power Plant,” Newsom said.

Another component of the plan was the recent completion of a 53-mile, 400 MW high-voltage direct-current submarine cable under San Francisco Bay (see Industry Watch, Electrical Contractor, January 2010). It can now provide up to 40 percent of the city’s peak-power needs and allows transmission of renewable energy from the north.

“I know that we can achieve 100 percent renewably generated electricity by 2020,” said Melanie Nutter, San Francisco environment director. “Some say it’s an impossible goal to achieve, but they said the same thing about San Francisco’s recycling goal, that we would never be able to achieve 75 percent diversion by 2010, but we did, in fact. We surpassed it and have already reached a 77 percent diversion rate.”