Glendale could become the last city in the state to power its electricity plant with natural gas after a vote this week.

While other cities, including Los Angeles, have decided not to use natural gas in the future, the Glendale City Council on Tuesday authorized the repowering of its aging Grayson Power Plant with five internal combustion engines which burn natural gas, a fossil fuel.

Fossil fuels generate smog emissions, such as nitrogen oxides and tiny particles, that enter the lungs and cause disease. They also produce carbon dioxide, which contributes to climate change, heating up the earth’s atmosphere, causing sea levels to rise, contributing to longer and more intense heat waves and other extreme weather.

The new plan approved Tuesday night is a blow to the Glendale Environmental Coalition and the Sierra Club, groups that have lobbied the city for two years to reduce its carbon footprint. The Glendale Environmental Coalition has been successful in changing local plans for total reliance on natural gas by increasing renewable sources such as solar and wind power in the next 10 to 15 years.

The coalition wanted the city to use only renewable energy sources. Still, the group was pleased by adoption of a city energy plan to buy more solar and wind energy and move ahead with clean energy.

“This is just the end of the beginning of our quest … to provide the city of Glendale with clean, safe renewable power for decades to come,” Mayor Ara Najarian said.

The City Council restricted the use of the engines as backup power during peak periods.

Glendale Water & Power will begin an environmental review to remove eight aging energy units at the plant situated at the junction of the 5 and 134 freeways. Before it can buy and install the engines, the city utility must present cleaner alternatives to the City Council.

For example, the utility plans to add 75 megawatts of battery storage to the plant, a new element that lowers the amount of fossil fuels needed.

Also, as part of the integrated energy plan ordered by the California Energy Commission, Glendale agreed to buy 130 megawatts of imported solar and 130 MW of imported wind energy; produce 13 MW of clean energy from residential units, 10 MW of solar from public spaces (such as empty lots) and about 28 MW of clean energy and energy efficiency savings from large and small commercial properties.

In April 2018, the City Council rejected a plan by Glendale Water & Power to repower the plant from 185 MW to 262 MW, a 41% increase, using natural gas. A new plan calls for only 93 MW of thermal power at Grayson, about one-fourth of the city’s peak demand.

Smog emissions will drop by 50% and carbon dioxide emissions will go to below zero when trades for carbon credits are factored in by 2030, according to GWP.