Los Angeles Mayor Antonio Villaraigosa intends to sign two agreements that will get the city off of coal-generated electricity entirely by 2025, according to reports flagged on Monday by the Sierra Club. Currently, the the Los Angeles Department of Water and Power (LADWP) relies on two coal-fired power plants — Intermountain Power Plant in Delta, Utah and the Navajo Generating Station in northern Arizona — for about 39 percent of its power.

Villaraigosa made the announcement last week at a green cities event sponsored by UCLA’s Institute of the Environment and Sustainability, just days after the “Forward On Climate” rallies brought tens of thousands of people out across the country to protest both the Keystone XL pipeline and the general lack of policy momentum to fight climate change — including 2,000 protestors in front of Los Angeles City Hall.

“We’ll be out of Navajo, 2015. Intermountain looks like 2025,” Villaraigosa said. “It will be a big deal.” About 39 percent of L.A.’s power comes from the two out-of-state coal plants now. The Navajo Generating Station in Arizona represents around a third of LA’s coal-fired power; the Intermountain Power Plant in Utah produces about two-thirds of that power, which along with natural gas remains cheaper than less-polluting renewable energy like geothermal, solar and wind power. During his second inaugural address in 2009, Villaraigosa announced plans for L.A. to eliminate coal from its energy portfolio by the year 2020. Subsequent shakeups at the top of the Department of Water and Power, a bruising political battle over a “carbon tax” and related energy rate increases slowed progress toward that goal.

Villaraigosa’s timeline for the Navajo plant matches up with recommendations put forward by the LADWP in its 2012 Integrated Resources Plan.

Getting a city of 4 million people off of coal-generated electricity, especially when it accounts for almost 40 percent of their total energy supply, was always going to be a heavy lift. So it’s no surprise the original 2020 goal fell short. A late 2011 report from the LADWP recommended scaling back that target, and Villaraigosa eventually agreed to pursue 33 percent renewables by 2020.

At the same time, Los Angeles actually hit another one of its recent environmental goals: getting 20 percent of its power from renewable sources in 2010. That same LADWP report warned that success could be temporary, with renewables falling back to 13 percent of L.A.’s portfolio in 2015 if further investments weren’t made. Hopefully, the $2.5 billion California voters decided to set aside in the 2012 elections for energy efficiency projects will help bring the complementary goal of more energy from renewables closer to realization.