BOSTON — Rechargeable batteries power computers, smartphones and countless electronic gadgets, and one day, they could be used to make the power grid more resilient, reliable and less costly.
As Massachusetts leans more on renewable energy sources, such as solar and wind, the state is also exploring how to store electricity using large-scale batteries and other technology.
Last year, Gov. Charlie Baker launched a $10 million study of the cost effectiveness of energy storage technology. Results are expected to be released by the end of the year.
Under a recently approved energy bill, state officials are also looking into mandating utilities to invest in storage in coming years.
“Energy storage could be a game-changer for reliably integrating renewable energy into the regional power grid,” said Judith Judson, commissioner of the Department of Energy Resources, whose office is conducting the study with the Massachusetts Clean Energy Center. “Because it allows renewable energies to be used at times when the sun isn’t shining and the wind isn’t blowing.”
Maximizing green energy
Solar and wind can produce plenty of energy, Judson said, but the renewables have a major problem with consistency. When the sun isn’t out, solar production drops. When the wind isn’t turning the turbines, power plunges.
Storing electricity can fill in the gaps, she said, maximizing the use of green energy.
When wind turbines or solar panels are most productive, excess energy can be sent to large-scale batteries. The batteries can then send electricity to the grid during periods of peak demand — or to smooth out fluctuations in power supplies.
“If a cloud passes over a solar facility and it stops generating for a few minutes, storage can fill in the difference,” Judson said.
But large-scale energy storage can be costly, and many efforts to do it are mechanical.
Industry officials say increasing storage — however it’s done — will do more than merely boost wind and solar power.
Matt Roberts, executive director of the Energy Storage Association, an industry trade group, said the biggest benefit is improving the overall reliability and cost-effectiveness of delivering electricity.
“Energy storage isn’t here to save renewables,” Roberts said. “It’s about storing energy when it’s plentiful and using it when it’s not, or moving energy across long distances and hold it for when you need it most.”
Electricity generated at power plants must be used as it is created, which means energy providers must match production with demand. Instead of shifting into overdrive to meet peak demand, power plants could run 24 hours a day at lower output and store electricity for times of heavy use, Roberts said.
Storing the electricity produced by natural gas and other fossil-fuel burning power plants would also reduce carbon emissions, he said, because plants wouldn’t have to ramp up production during peak periods.
Already happening elsewhere
Energy storage technology is already being used to deliver electricity in California and other states.
Pumped hydro — which involves forcing water uphill alongside dams, then releasing it to generate power — is the biggest source, accounting for 96 percent of the storage industry’s capacity, according to the U.S. Energy Information Administration.
The use of compressed air, stored under pressure in natural underground caverns, is also being explored. During peak times, air is released into a chamber that turns a turbine, generating power as needed.
And flywheels — large metal discs spun at high rates of speed to store energy — are also being used.
Massachusetts faces an energy crunch as the state looks for ways to offset an expected loss of 10,000 megawatts from coal- and oil-burning plants that will be closing in coming years.
Besides energy demand, the Baker administration is committed to cutting the state’s carbon output by 25 percent of 1990 levels within four years, by tapping into renewables.
Last month, Baker signed a wide-reaching energy bill that requires utilities to pursue long-term contracts with hydropower suppliers and offshore wind developers. It also requires the state to explore storage options for renewable energy.
Power plant generators have resisted the state mandates for hydro and wind, arguing that they will stifle competition and ultimately drive up costs. It’s not clear if they also oppose a storage mandate.
In California, the first state to set storage mandates, utilities must procure at least 1,325 megawatts of storage by 2024.
Judson said Massachusetts hasn’t decided whether to set a similar mandate, but the energy bill requires state officials to sort it out by the end of the year. If the state adopts mandates, costs likely will be passed onto ratepayers.
Judson said short-term costs would be offset by using stored electricity to meet peak demand.
“Storage has tremendous potential to reduce costs for ratepayers by enabling lower cost energy to supply homes and businesses when demand is high,” she said. “If we lower the cost of energy during peak demand, it will make a big difference on energy bills.”
Cost of storage
The cost of battery technologies remains a major hurdle. Industry estimates range anywhere from $100 to $500 per kilowatt hour for energy storage — which is much higher than conventional electricity sources.
Judson points out that the cost of battery technology has dropped in half in recent years, and will likely continue to fall.
Large corporations like General Electric and a handful of startup companies in the state are racing to develop the next generation of batteries for energy storage.
“We’re still at the technology development stage, but it’s looking very promising,” said Phil Giudice, president and CEO of Cambridge-based Ambri Inc., which is developing a liquid metal battery that has its origins at the Massachusetts Institute of Technology.
“I think it’s great that the state is taking a leadership role in helping develop the storage industry,” he said. “The market will determine the winners in coming years.”
Eversource, the state’s largest utility, is developing storage technology as part of a long-term modernization plan.
“Energy storage is an important and evolving technology and we support the efforts currently underway to expand its role in meeting the future demand for electricity,” said Michael Durant, an Eversource spokesman.
Environmental groups support the effort because it will boost the state’s reliance on renewable energy over fossil fuels.
“Storage definitely enhances the value of solar and wind power, which is good for the environment,” said Janet Gail Besser, vice president of the Northeast Clean Energy Council. “But the bottom line is it will increase the efficiency of operating the grid.”
Christian Wade covers the Massachusetts Statehouse for the Times and its sister newspapers and websites. Reach him at email@example.com.