Grid-scale batteries gain ground, research continues to seek lower cost
WASHINGTON – For years, the idea of storing electricity on the power grid might have been chalked up as science fiction. Demonstration projects proved too expensive. Scientists struggled to even guess which technologies might ultimately prove out.
But as large-scale battery projects increase around the country and research matures, a commercially viable means of storing the large volumes of electricity demanded by the power grid now appears to be in sight.
At a meeting on Capital Hill earlier this month, George Crabtree, director of the federal government’s Joint Center for Energy Storage Research, said his team of scientists had identified a technology they believed would one day to store electricity on the grid economically.
“The technology isn’t quite there yet, but we have a direction that looks promising,” he said. “A lot of people are following us and watching what we’re doing.”
The rush to develop a battery large enough and cheap enough to make storing electricity on the power grid feasible has long seemed an elusive goal.
The ability to generate electricity and store it until it’s needed would provide solutions to some of the power grid’s most vexing problems, including the cost of maintaining large fleets of power plants that only operate a few times a year when electricity demand peaks, and the increasing instability of electrical current as weather-dependent wind turbines and solar panels proliferate.
After years of research and development, the era of the battery is beginning to take shape, industry analysts and executives said. As cities and states, such as Austin and California, force utilities to install energy storage systems, more projects are getting built, technology is advancing, and costs are coming down.
“Storage has been that mystery in the past where we in the electricity sector have a product that’s demanded instantaneously,” said John Chillemi, executive vice president for national business development at NRG Energy. “It’s still relatively small, but the economics are getting lower and more competitive.”
Around the country hundreds of small-scale projects have gone up in recent years, largely concentrated in California, said Sam Jaffe, managing director of Cairn Energy Research Advisors in Colorado. Earlier this year Austin Energy, the city owned utility, announced it was building two grid-scale batteries connected to solar power projects within its service area after receiving a $4.3 million grant from the Department of Energy.
Obstacles in Texas
In deregulated electricity markets like most of Texas, where the lowest cost means of generation wins out, energy storage largely remains too expensive. Still, battery projects are not unheard of; the power company AES Corp. and the transmission company Oncor launched one in Dallas to help regulate power.
“We definitely are at an acceleration point,” Jaffe said. “You’re starting to see project you wouldn’t call pilots anymore, big large projects.”
So far, energy storage has largely gravitated around lithium ion technology, the same form of battery used to power smartphones and laptops. Costs have come down fast as companies like Tesla and Panasonic refine the manufacturing process for use in cars and grid storage systems.
But as anyone with a smartphone knows, lithium ion’s lifespan is limited, with a steady loss of capacity as the years tick away. That might not be much of a problem for personal electronics or even cars, but power industry equipment is expected to last 20 years.
Instead, many scientists are turning towards what is known as flow battery technology, which stores energy by shifting electrical charges across liquids and is believed to have a lifespan of decades. Scientists at the federal Joint Center for Energy Storage Research have already committed to the technology for grid storage after spending more than three years exploring alternatives, Crabtree said.
“Everyone says batteries are at the place solar was 10 years ago,” he said. “As you know, the cost of solar has come down and the quality has gone up. Now they’re getting installed like mad.”
As the United States works to meet climate change goals agreed to in Paris last year, clean energy sources like wind turbines and solar panels are expected to play an ever larger role in the decades ahead. But in places like California, where renewable penetration is already high, the rush to build means open land is disappearing and grid operators are struggling to deal with drop-offs in energy generation when clouds pass overhead.
“If we can not store this energy, we’re going to be using so much of our land it might become a problem,” Rep. Steve Knight, R-California, said at a congressional hearing last week.
Rush has begun
A rush is on among companies large and small to develop a commercially viable battery for the grid, from humble startups to giants like Bosch and Duracell.
UniEnergy Technologies, headquartered outside Seattle, switched on what they said was North America’s largest energy storage system – a flow battery that disperses a full megawatt of power for 4 hours – for a small utility in western Washington last year. Now UniEnergy is working with its sister company to build a battery 200 times that size under a contract with the Chinese government.