Electricity Markets

Study Examines Balancing New England Energy Supply Adequacy, Renewables

Maintaining energy adequacy will be a challenge as non-dispatchable, renewable resources proliferate, according to a new study by ISO New England.

The study, 2021 Economic Study: Future Grid Reliability Study Phase 1, requested by the New England Power Pool (NEPOOL) stakeholders, evaluated how the region’s grid would perform under the double burden of increased levels of variable, i.e., renewable, generation sources and higher demand.

Five of the six New England states have committed to reducing their carbon dioxide emissions by at least 80 percent in the coming years and electrification of heating and transportation is rapidly accelerating, the report noted.

 To ensure energy adequacy, the New England region would likely require significant dispatchable resources such as natural gas or stored fuels for periods when variable resources are unavailable, the report found. In addition, battery storage. which is often held up as a remedy for shortfalls in renewable generation, may have difficulty sufficiently charging under predicted system demand curves, the report’s authors said.

The authors also pointed out that the retirement of the region’s two remaining nuclear power plants, which has been assumed in some planning scenarios, would further challenge reliability and state decarbonization goals.

“The region may struggle to maintain necessary operating reserves in scenarios of high electrification and more aggressive retirements of existing resources,” the report’s authors said. “The reserve margin may need to increase by an order of magnitude by 2040.”

The authors also argued that higher levels of renewable resources that would be needed to decarbonize the region’s grid would increase the need for demand flexibility. That would translate into an increased need for regulation services as the flexibility of both generation and demand resources may be needed to maintain the balance of the region’s grid.

The report used several scenarios to study assumptions about the future of New England’s grid. The baseline, moderate and import-supported decarbonization scenarios all contained moderate amounts of renewables and met reliability criteria. The baseline and moderate scenarios, however, did not meet state electric sector environmental goals. The import-supported scenario met state electric sector environmental goals but did not include expected high levels electrification of heating and transportation.

The deep decarbonization scenario lowered production costs and met state electric sector environmental goals while supporting high electrification of heating and transportation, but did not meet required reliability criteria, the report found.

A modified version of the deep decarbonization scenario, resource-adequate deep decarbonization, was adapted to meet reliability criteria through a balanced mix of increased wind, solar, and storage – 89,000 megawatts (MW) versus the current roughly 5,600 MW – but would require such a large amount of wind and solar that it may present “significant challenges” to the region’s transmission system and require an “outsized amount of land or offshore areas to be sited and developed for the necessary wind and solar farms,” the report found. However, the substitution of 3,000 MW of dispatchable units would reduce the necessary new units of wind, solar, and storage by 19 percent, or 17,000 MW, illustrating “the importance of dispatchable resources to the future grid,” the authors said.

The Future Grid Reliability Study is “a turning point” for our region, the report’s authors said in conclusion. “Many existing long-term assumptions were called into question as part of this analysis, and results show that the methods by which the ISO and region at large evaluate future grids require an overhaul.”

The ISO said it would issue three technical appendices to the report covering production cost, ancillary services, and resource adequacy later this year. The ISO also said a second phase of the Future Grid Reliability Study would analyze how “future grid scenarios might operate under today’s wholesale electricity markets to ensure an economically sound future grid.”