Dozens of gray compartments, lined neatly in rows, inhabit a boxy concrete building on the edge of the impoverished border town of Presidio. The only sound, aside from occasional clanking, is the whirring of air-conditioners to keep the compartments cool.
This $25 million contraption is the largest battery system in the United States — locals have dubbed it Bob, for Big Ole Battery. It began operating earlier this year, and is the latest mark of the state’s interest in a nascent but rapidly evolving industry: the storage of electricity.
Storage is often referred to as the holy grail of energy technology, because it can modernize the grid by more efficiently matching demand for power with the generation of electricity. A variety of early-stage technologies are being studied in Texas, ranging from the Presidio battery (which can power the town of about 4,000 people for up to eight hours in the event of a power failure) to superconducting magnets to caverns that would store and release air compressed by electricity.
The state is especially keen on storage because of the proliferation of wind turbines in West Texas. The machines generate the most power at night, when people are sleeping — so if their power could be stored for use during the day, the usefulness of wind power, which currently accounts for about 6 percent of the state’s electricity generation, would significantly increase.
“Storage has been an elusive goal of our industry for a long time,” said Barry Smitherman, the chairman of the Public Utility Commission, which regulates the operations of the state’s electric grid. “I think there’s a lot of great R&D being done in this area.”
The Presidio project does not back up the wind power, although future versions of the battery system could be used for such purposes. Instead, the four-megawatt sodium-sulfur battery is supposed to help provide a steadier electricity supply for the town, which sits at the end of a 60-mile transmission line built in 1948. The line — still with many of the original wooden poles — is often struck by lightening, causing power failures. A transmission line company, Electric Transmission Texas, plans to replace the line by 2012, but it installed the battery to keep the lights on in the meantime, as well as after the new line is built.
The concept of electricity storage has been around a long time. Decades ago, rural off-grid ranchers could buy batteries to back up their small wind turbines, but they stored only enough electricity to at least partially power a single home — far less than the Presidio battery.