Last year, San Diego's city council voted to commit the city to using 100% renewable energy by 2035.
Last week, San Diego reiterated its pledge to renewable energy and other sustainable strategies, such as eliminating half of all greenhouse gas production, in a Climate Action Plan memorandum.
While the city's plan is still in its nascent stages, San Diego's news sparked articles by a dozen or so publications because it is the largest city to commit to an all-renewable power grid.
With more than 1.37 million people, San Diego is the eighth-largest city in the U.S. and the second largest in California behind Los Angeles.
Currently, the San Diego's electrical grid is about 33% renewable as provided by the utility, San Diego Gas & Electric.
"We will be doing a feasibility study for a Community Choice Aggregation (CCA) program this year, which is one potential mechanism to achieve our 100% renewable electricity goal," a city spokesperson wrote in an email reply to Computerworld. "As of now, we don't know what percentage we expect from the different types of renewable energies."
If San Diego's CCA program is successful, the city would procure energy to supply its customers directly from the open market and some from distributed generation, such as rooftop solar feed-in from systems that produce excess electricity.
"We also currently produce renewable energy for our own operations and would likely continue to expand that," the spokesperson said.
While it is the largest city to commit to an all renewable energy plan, San Diego isn't alone. For example, last year, Aspen, Colo., announced it had reached its goal of 100% renewable energy, most of it from wind (53%) and hydroelectric sources (46%).
Other U.S. cities that have already reached their 100% renewable goal are Burlington, Vt., Greensburg, Kan. and Ithaca, N.Y., which gained its green status through the purchase of renewable energy credits (RECs). RECs are provide a tax credit that can be traded with other government and private organizations to achieve renewable energy goals.
For example, if one corporation or municipality has achieved its renewable energy goal, it can trade additional RECs to other organizations that can use them to achieve their clean energy quotas.
San Jose, California's third-largest city, also plans to go all-renewable by 2022, according to the California-based Renewables 100 Policy Institute, which helps promote renewable energy transition projects.
Other major U.S. cities that have even more ambitious goals than San Diego include Cincinnati, Ohio; Grand Rapids, Mich.; Hillsboro, N.C.; San Francisco, and Santa Cruz, and Lancaster, Calif, according to the institute. Both San Francisco and Lancaster plan to reach their 100% renewable energy goal by 2020.
Along with renewable energy, San Diego plans to increase the number of zero emissions vehicles in the municipal fleet to 50% by 2020 and 90% by 2035.
But even as major U.S. cities are committing to renewable energy, only a small percentage of the nation has gone green.
As of 2014, only about 11% of electricity in the U.S. is supplied by renewable sources, such as wind, solar and hydroelectric, according to the U.S. Energy Information Administration (EIA). Another 9% comes from nuclear power plants. By 2040, the EIA projects only 15% of U.S. power will come from renewable sources.
The rest of the power consumed in the U.S. comes from natural gas (31%), petroleum (26%) and coal-fired generators (24%), the EIA stated.