Portland General Electric, the utility serving Portland, Oregon, announced Friday it is putting in the second-largest battery storage installation in the United States, at 400 MW of power. The significance of such projects is they diminish the need for power plants that burn fossil fuels that warm the planet.

The only larger standalone project in the country is Vistra Moss Landing in California, currently at 400 MW, but it will soon add an additional 350.

The Portland project will generate enough electricity for around 260,000 homes, roughly the size of the city, for four hours at full power.

"Although we are a small utility, I like to think we punch above our weight," said Brett Greene, PGE's senior director, calling it an important step towards reducing carbon emissions 80% by 2030.

Batteries are playing a critical role in the clean energy transition because they supply electricity during times of low sunlight and wind, and can also prevent blackouts when demand for electricity surges, such as heat waves. The battery power during peak periods also helps avoid the need to buy "extremely expensive" energy from other utility providers, Greene explained.

"Batteries are like a huge refrigerator for electrons," said Shirley Meng, a professor at the University of Chicago's Pritzker School of Molecular Engineering.

Batteries let us capture electrons created when sunlight strikes solar panels or the wind spins a turbine, which is how we can use solar power at night after the sun has set, for example, Meng explained.

Batteries also help the grid cope with "rush hour," when energy usage spikes around 5 p.m. as people come home from work and turn on lights, start cooking and run their air conditioning, explained Jiangbiao He, an assistant professor of engineering at the University of Kentucky.

Renewable energy projects are now being added to the grid faster than battery storage, and that concerns him, He said.

"Solar and wind came to the markets decades ago, but utility-scale energy storage really only came onto the scene after 2010," He explained. "We definitely have more renewable energy integrated into our grid every year than we do energy storage. There is a major market demand for utility-scale batteries."

He said the current utility-scale battery capacity in the U.S. is around 8 GW but by 2030 that will more than double.

"Once you start getting north of 30% of electricity being produced by renewables, you're going to need battery storage," said University of Virginia professor Michael Lenox.

California gets about 60% of electricity from clean sources, according to the Energy Information Administration, if you count nuclear power, which does not contribute to climate change.

Batteries are becoming cheaper and the U.S. is making more of them, which is why Lenox believes "batteries in the short run, and maybe even in the long run, are going to be the primary sort of solution to the storage problem."

The new PGE battery project was made possible partially by the new Inflation Reduction Act, which offers investment tax credits for battery storage projects.

PGE refers to the new installations as a single project although they are located at separate sites across town, one in North Portland and one in Troutdale. Eolian L.P., the developer, recently brought similar battery projects online in Texas and plans to begin construction in Portland later this year.

In addition to government support, Greene noted that many states along the West Coast are "the most progressive when it comes to decarbonization," which helped build support for this initiative.

"This is something our customer base and the population of Oregon want," Greene said.

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