Sometime this quarter, a shovel will sink into the dry desert soil of a Mexicali industrial park, breaking ground for the construction of an unprecedented energy-storage facility. Once completed, its batteries will be able to feed a full gigawatt into the grid for 4 to 6 hours.
By far the largest installation of its kind anywhere, it will help keep the lights on in Baja California and in the future, Southern California, just across the border. It should also improve the reliability of both the Mexican and U.S. grids and pave the way for using more solar and wind power. And with dozens of other battery--based energy-storage projects in the works elsewhere in the world, 2012 may be a turning point for the electricity industry—where up to now, adding new capacity has always meant building an expensive new power plant.
At press time, Jacob Rikard Nielsen, vice president of business development for Rubenius, the Dubai-based company behind the Mexicali project, said plans were still being finalized, including a timeline for the project and the type of batteries it would use. The work builds on two smaller energy-storage sites the company has installed in Abu Dhabi, which use sodium-sulfur batteries from the Japanese company NGK.
One of the chief drivers of the Mexicali project is California’s goal of having 33 percent of its electricity come from renewable sources by 2020. “They’re already seeing problems today in terms of grid stability and flexibility,” Nielsen says.
Eric Wesoff, an industry analyst with Greentech Media, explains why: “A wind farm only works when the blades are spinning. It might have a nameplate capacity of 100 megawatts, but it never puts out that much. Sometimes it’s 70; sometimes it’s nothing. To a grid operator, that kind of resource is a headache rather than an aspirin.” To compensate for solar and wind’s fitfulness, utilities end up building more gas turbines.
Using a bank of batteries allows utilities to even out the supply of renewable electricity. “So now that 100-MW wind farm can say, We’re a 40-MW, steady-state, 24/7 energy source—more like a coal plant,” Wesoff says. “That’s more valuable to society.”
Utilities have long avoided batteries, because the technology was too expensive and not robust enough to last for tens of thousands of charging cycles. At present, the world’s biggest grid-scale battery [PDF] is a bank of nickel cadmium cells in Fairbanks, Alaska, which can produce up to 52 MW of emergency backup power for about 15 minutes.
Some electric utilities store energy by pumping water uphill and then recapture the stored energy by allowing the water to flow back downhill through turbines. Worldwide, pumped hydro facilities can produce about 127 gigawatts this way. Compressed air is also used as a storage medium, a strategy that yields just a few hundred megawatts in total, about as much as battery-based energy-storage facilities can now produce.
But thanks to investments made by the consumer-electronics and electric-vehicle industries, battery technology has advanced enormously in just the past decade. “Today you’ve got two or three batteries on your person at all times,” notes Haresh Kamath, program manager for energy-storage research at the Electric Power Research Institute (EPRI). “The research applied to those industries is now being applied to batteries for the grid.”
The potential market for grid-scale storage is substantial. Rubenius estimates it at US $30 billion per year, “plus or minus $5 billion,” Nielsen says. “Of course, that’s not going to materialize tomorrow. But as the technology matures and utilities gain experience, we’ll get to that market status in the next 10 years. I’m quite optimistic.”