NRG Energy Inc. and Exelon Corp.’s Constellation unit say interest in combining solar power with battery storage has soared in the year since Hurricane Sandy knocked out power to millions of homes and businesses on the East Coast.
They are among more than a dozen solar providers that have introduced or enhanced in the past year systems that combine rooftop solar panels that generate power and batteries that retain electricity to use later.
People with solar-powered homes and businesses were frustrated to discover that losing power from local utilities also knocked out the inverters that connect rooftop panels to the grid, leaving them unable to tap the electricity they were producing. Adding battery storage solves that problem, said Tom Doyle, chief executive officer of NRG’s solar unit. It’s also a growing threat to utilities.
“When Sandy came along we really didn’t have a product to keep solar power flowing during blackouts,” Doyle said in an interview yesterday at the Solar Power International conference in Chicago. “Now we can install systems that continue operating when the grid fails, and the costs are coming down.”
Battery storage can add more than 20 percent to the cost of a typical 10-kilowatt solar system for a four-bedroom home, Brendon Quinlivan, director of solar development at Constellation, said in an interview.
“It provides an extra layer of security,” he said. Some people are also using natural gas microturbines or fuel cells to generate their own electricity.
SolarCity Corp., Kyocera Solar Inc., S&C Electric Co., Standard Solar Inc. and Blackstone Group’s Vivint Solar unit have also expanded their rooftop solar offerings to include battery storage.
“To really get solar mainstream, you need storage,” Tony Clifford, chief executive officer of Rockville, Maryland-based Standard Solar, said in an interview.
The systems typically use lithium-ion batteries. They can also maintain power for critical services during emergencies such as gas stations along evacuation routes, medical centers and cash machines.
“It’s not just about the ability to disconnect from your utility when you want to, it’s improving lives in times of crisis,” said NRG’s Doyle.
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