The New York Independent System Operator has released its annual Summer Reliability Assessment, finding that the reliability margin under baseline summer conditions is 417 megawatts — the lowest margin in recent history.

The report forecasts reliability challenges under extreme temperature scenarios despite the addition of new capacity in the past year. Aging generation, transmission constraints, and rising demand pose major challenges as reliability margins continue to decline.

The NYISO is a not-for-profit corporation responsible for operating the bulk electricity grid, administering the competitive wholesale electricity markets, conducting comprehensive long-term planning, and advancing the technological infrastructure of the electric system serving New York state.

The assessment notes that 34,615 megawatts of power resources are available to meet forecasted peak demand of 31,578 MW. As established by the New York State Reliability Council, under normal system conditions, the NYISO is required to maintain 2,620 MW from the available resources in reserves.

“This assessment reflects the challenges of the grid in transition — declining reliability margins, performance issues with aging generators, and an absence of new dispatchable resources,” said Aaron Markham, vice president of operations for the NYISO, in a release announcing the report.

“Coordination with generation owners, utility companies, neighboring grid operators, and government officials will be essential,” he went on, “as we work to maintain grid reliability this summer.”

Under extreme weather scenarios, reliability margins are forecasted to be deficient. For example, if the state experiences a heatwave with an average daily temperature of 95 degrees lasting three or more days, the capacity margin is forecasted to be -1,679 MW.

That number declines further to -3,370 MW under an extreme heatwave with an average daily temperature of 98 degrees.

Under those conditions, NYISO operators would initiate emergency operating procedures to secure up to 3,166 MW to maintain system reliability.

The NYISO may issue grid alerts if reserve margins drop below regulated levels. These alerts are designed to raise awareness about grid conditions and inform the public if electricity conservation is necessary.

The all-time record for peak demand of 33,956 MW was set on July 19, 2013.