Energy storage

After nearly two decades of stagnation, U.S. electricity demand is surging, driven by growing numbers of electric cars, data centers and air conditioners in a warming climate. But traditional power plants that generate electricity from coal, natural gas or nuclear energy are retiring faster than new ones are being built in this country. Most new supply is coming from wind and solar farms, whose output varies with the weather. That’s left power companies seeking new ways to balance supply and demand. One option they’re turning to is virtual power plants. These aren’t massive facilities generating electricity at a single site. Rather, they are aggregations of electricity producers, consumers and storers – collectively known as distributed energy resources – that grid managers can call on as needed. Some of these sources, such as batteries, may deliver stored electric power. Others may be big electricity consumers, such as factories, whose owners ha...

The U.S. is nearing the end of one of its hottest summers on record. Across the nation, heat waves have driven peak electricity demand on some days to levels far exceeding seasonal averages. Grid operators rely on so-called “peaker” plants to ensure they will have enough supply to meet these demand surges. Peaker units can start up quickly and at relatively low cost, but they typically burn more fuel per unit of electricity produced than other types of fossil fuel units. Because they are less efficient than other plants, peakers typically run only during high-demand periods. Historically, peakers have run for less than 10% of the year, often for just a few hours at a stretch. Nonetheless, their higher emissions per unit of electricity produced raise environmental and health concerns. As of 2021, there were 999 peaker plants across the U.S., in all 50 states. About 70% of these plants burned natural gas, and the rest were powered by oil and coal. To reduce air p...

In areas where storms or extreme heat and cold have knocked out the power for days at a time, people are starting to ask whether investing in rooftop solar and battery storage systems can keep the lights on and the air conditioner running when the power grid can’t. When the grid goes down, most solar systems that lack a battery will also shut down. But with batteries, a home can disconnect from the grid. Each day, the sun powers the home and charges up the batteries, which provide power through the night. Our team at Berkeley Lab explored what it would take for homes and commercial buildings to ride out long power outages, of three days or more, with solar and batteries. How much can solar + storage do? For a 2022 report, we modeled a generic power outage for every county in the U.S., testing whether a rooftop solar system combined with a 10- or 30-kilowatt-hour battery could power critical loads, like refrigeration, lighting, internet service and well pumps; if it could...