With Renewable Energy Comes Need for Large-scale Battery Storage

A rendering of AES's planned battery storage facility in Los Alamitos
A rendering of AES’s planned battery storage facility in Los Alamitos

Although exploding smartphone batteries have captured public attention lately, utilities around the country are battling an even bigger battery challenge—the need to create storage, said experts at the fall Engineering Distinguished Lecture Thursday.

Increased generation of renewable energy—especially solar—is quickly changing the game for utilities. Previously, nonrenewable energy allowed utilities in the state to better synch power generation with use in keeping with the requirements of the California Independent System Operator, which manages energy flow for 80 percent of California.

That is becoming difficult to do, however, with solar. The bulk of solar energy is generated during the day when the sun is out. But peak energy use comes after people get home from work and the sun goes down, creating an energy imbalance

State mandates to increase renewable energy production will only exacerbate the disconnect between energy supply and demand.  In California, state-regulated utilities must get 50 percent of their electricity from renewable energy sources, such as wind, solar, and hydro, by 2030.

San Diego Gas & Electric Manager of Advanced Technology Integration Josh Gerber, a speaker at the lecture, said numerous states have mandates for double-digit percentages of renewable energy production. But none is as ambitious as Hawaii’s, which calls for 100 percent renewable energy production by 2045.

“There are some pretty aggressive standards out there,” he said.

Jennifer Didlo ’02, Market Business Leader of AES Western Region, said the grid operator used to be able to predict loads. They factored how solar would affect the balance, but underestimated how much solar would be generated.

To make these mandates work, utilities will need large-scale storage—and fast. A variety of means can be used for energy storage: lithium-ion batteries, flow batteries, molten salt, sodium sulfur, hybrid systems, pumped hydroelectric storage, compressed air, flywheels, and hydrogen.

San Diego Gas & Electric has two “expedited storage projects”—a 7.5 megawatt/30 megawatt-hour array in El Cajon and a 30 megawatt/120 megawatt-hour array in Escondido.

Didlo said AES has been working with battery storage around the world for eight years. “We have batteries doing all kinds of things,” she said. AES is seeking to build a 300-megawatt battery facility in its plant on Studebaker Street.

“We’re pretty excited about what energy storage will bring to the grid,” she said.

Taison Tan, Technical Staff Senior Member of The Aerospace Corp., is an expert with lithium-ion batteries. During the lecture, he explained batteries in smartphones may be overheating. The most common reason for “thermal runaway,” is foreign object debris, or FOB. Such debris can contaminate batteries during the manufacturing process.

Manufacturers, meanwhile, are using a variety of methods to screen out debris, such as x-rays, ceramic screens, and new cell designs. “Battery cell manufacturers should be implanting as many screens as possible,” Tan said.