A utility-scale battery storage system in Odessa, Texas, operated by Broad Reach Power. Battery storage systems can be used to provide short-term boosts of power during outages and when power from renewable sources wanes, such as solar panels during evening hours.
Green-power advocates are keeping up pressure on the overseer of the New England grid in an attempt to push ISO New England to better factor in the threat that limited supplies of natural gas could pose in creating power outages during dangerous stretches like cold snaps or heat waves — with dozens of battery storage projects now in the works that could help.
On Thursday, the Sierra Club published a Synapse Energy Economics study it had commissioned on the difficulties New England could face in firing up emergency power plants at a moment’s notice, picking up the slack during any “capacity deficiency” when one or more plants may be forced offline unexpectedly.
That scenario occurred on Christmas Eve last year. Multiple New England power generators, which authorities have not identified by name, went offline during a cold snap, raising the specter of rolling blackouts. ISO New England stated in January the power-plant issues centered on mechanical problems rather than any restricted access to natural gas.
“It’s an issue we’ve had our eye on for a long time,” Casey Roberts, a Colorado-based attorney with the Sierra Club, told CT Insider. “If the system operator doesn’t really look at how quickly things can respond, then it’s not going to be able to factor that into its reliability planning. Right here with ISO New England, their capacity accreditation process ignores this whole issue.”
During another cold snap in early February, power supplies were again on shakier ground according to the New England Power Pool trade group, as ISO New England was forced to revise twice its projections upward on how much power the grid needed, and as some plants encountered mechanical difficulties.
“The February 4 load forecast was inaccurate throughout the day,” NEPOOL reported this month. “In total, across the February 3-4 operating days, (about) 2,400 MW of generating capacity was unavailable during peak hours due to unexpected outages or reductions.”
NEPOOL added natural gas supplies did not contribute to the problems in early February, and that the New England grid was able to meet demand even as it exported about 1,000 megawatts of power to Quebec to help the province meet record power demand.
ISO New England is developing what it calls a Resource Capacity Accreditation model as more renewable sources of electricity get added to the grid which have variable production depending on conditions; and given extreme weather events over the past dozen years. But the Synapse report says that model does not include the hours to get a plant from “cold start” status to the point where it is pumping enough electricity to cover for any shortfall.
An ISO New England spokesperson declined comment on the study.
“The ISO carries operating reserves for just this purpose, and region was several steps away from needing controlled power outages to maintain system reliability,” stated ISO New England spokesperson Matt Kakley. “The Resource Capacity Accreditation project underway aims to find the best way to account for the reliability contributions of the different resources that will comprise the future grid.”
Kakley added that includes factors like the correlated performance of intermittent resources; differences in the maximum stored energy levels of different sources of power; and the ability of natural-gas-fired plants to have an adequate supply of fuel during winter blasts.
New England is dependent on natural-gas power plants for more than half of its power, and on the Millstone and Seabrook nuclear power plants for roughly another quarter. Connecticut lawmakers want to reduce dependence on natural gas over time as more solar arrays and wind farms come online, and through conservation.
Multiple battery farms are now in the works in Connecticut that could provide short-term boosts in electricity, including in Milford. Danbury-based Cadenza Innovation is among the companies nationally developing utility-scale battery storage systems.
NEPOOL says as many as 85 additional battery storage projects are in varying stages of the proposal process for the New England region totaling more than 13,000 megawatts of capacity, with the likelihood only some of those will be built in the near-term as “peaker” sources of power.
The Federal Energy Regulatory Commission held a Vermont conference last September on the challenges New England faces in its dependence on natural gas for power, with a follow-up scheduled for June in Portland, Maine. Last month, FERC dismissed a challenge by the advocacy groups RENEW Northeast and the American Clean Power Association which had argued ISO New England exercises “undue preference” for natural gas plants without factoring in uncertainties for supplies given pipeline capacity into the region. But FERC urged “prompt action” by ISO New England to better address any “reliability concerns” in depending on natural gas for electric power.
To cover emergency scenarios during periods of intense consumption like heat waves and arctic temperatures, ISO New England can institute “operating procedure four” which asks “peaking” plants to fire up turbines to generate extra electricity. But it is not the equivalent of flipping a switch, particularly in the case of oil-fired peaking plants which can take several hours to generate enough electricity to fill any major gap.
Roberts said that while battery storage can fill any power gap in the span of minutes or even seconds, they come with the drawback of being able to provide power only for hours before losing their juice. But she added that is not deterring other states in turning to batteries for emergency power supplies, and to store power from solar panels that can be tapped in the evening hours as household power consumption picks up.
“Outside of New England, there are some parts of the country that are adopting batteries at a breakneck pace, like California for example,” Roberts said. “You can look at all the generators including storage that are trying to get onto the system, and batteries make up an enormous percentage of that interconnection queue waiting to get approval to inject power into the grid. There’s a big economic case for it.”
Includes prior reporting by John Moritz and Luther Turmelle.