ISO-NE Fails to Consider Resource Inflexibility During Accreditation, Says New Report

Fossil Fuel Plants Benefit as ISO-NE Ignores Slow Start-Ups in Reliability Planning

Bianca Sanchez,

Shannon Van Hoesen,

BOSTON, MA. --  Long start-ups and other time constraints are not adequately considered when determining energy resource value at ISO New England, according to a new report authored by Synapse Energy Economics, Inc. The result is less grid reliability than consumers pay for and an unfair advantage for polluting, slow-to-start fossil fuel plants over renewable alternatives and fast-acting energy storage. 

In recent years, the New England power grid has inched closest to blackouts during rapidly developing emergencies, including Winter Storm Elliot this winter. The new report titled “The Impact of Resource Inflexibility on Capacity Accreditation in New England,” examines the speed at which seven fossil fuel and biomass units power and the value ISO-NE assigns to each during their Capacity Accreditation process. 

On average, the seven coal, oil, and biomass units included in the report took between seven to 23 hours to start up. Merrimack Station in New Hampshire, New England’s largest remaining coal plant, took between 12 to 14 hours to start. Long start-up times prevent resources from showing up for the grid when New England needs them most. On December 24, 2022, ISO-NE had just a few hours to prepare for an unpredicted energy shortage caused by Winter Storm Elliot. That day, 8,500 MW of available generation sat on the sidelines unable to start up in time to alleviate the energy strain.

Despite the clear risks, ISO New England ignores slow starts and similar time considerations when it determines the capacity value of these resources–a process essential to determining regional grid reliability. Although ISO-NE is currently updating its approach to capacity accreditation, the proposed changes will not address the risks posed by resource inflexibility. Failing to consider a unit’s ability to respond rapidly to emergencies favors polluting fossil fuel plants and disadvantages reliable, clean energy sources like battery storage. 

In response to the report, Casey Roberts, Senior Attorney for the Sierra Club’s Environmental Law Program, issued the following statement. 

“A fossil fuel generator that takes 12 hours to start up is useless for responding to urgent and unpredictable energy emergencies. By making the illogical assumption that all units can start up at a moment's notice, ISO-NE overvalues slow-to-start fossil fuel resources like coal, oil, and biomass. It is critical that ISO-NE update its capacity market rules to address this significant short-coming. By doing so, ISO-NE will improve grid reliability and ensure that New England energy consumers pay for units capable of responding to unforeseen drops in energy supply.”

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