In what could be considered one of the most aggressive moves towards green energy of all major U.S. cities, San Francisco is making a huge leap by aiming to have a 50 percent renewable energy supply by 2020. For businesses and residents, it doesn’t involve much more than enrollment in a program: They can work with CleanPowerSF, the city’s renewable energy program, who’s partnered with utility company PG&E.

With ambitious renewable energy goals on a broader scope, the city realizes it can’t reach “deep greenhouse gas emissions reductions and avoid global climate crisis … without the accelerated expansion of CleanPowerSF,” said Debbie Raphael, Director of the San Francisco Department of the Environment, in a press release. 

Currently, 29.5 percent of the city’s energy comes through renewable sources, with customers unable to choose how their energy is derived. However, CleanPowerSF will generate 10.5 percent more energy from sources such as wind and solar. There’s also the SuperGreen option, in which 100 percent of energy comes from renewable sources courtesy of PG&E. Another plan for achieving the city’s goal is to expand Hetch Hetchy hydro-electric resources to reduce greenhouse gas emissions. The odd sounding resource is a reservoir that can hold up to 117 billion gallons of drinking water, which would serve millions in the Bay Area.

New housing must also decide between two choices to help better the environment: implementing green roofs (i.e. ones with vegetation), which are popular in the South of Market, Downtown, and Haight neighborhoods, or solar panels.