Dive Brief:

• New York's sole remaining coal-fired generator has filed with regulators to shut down as soon as Feb. 15, but the state's grid operator must still determine whether the 685 MW Somerset plant in Niagara County is needed for reliability. Officials say they expect it to be online this winter.
• The New York ISO expects to have sufficient capacity to meet forecasted electricity demand this winter on even the coldest days. A month ahead of winter's official start, the grid operator is anticipating a peak demand of 24,123 MW for the season, against more than 43,000 MW of system resources.
• Extreme temperatures could send demand higher, but the ISO is confident the electric system will remain reliable. New York’s all-time winter peak reached 25,738 MW in 2014. The ISO's statewide fuel mix is more than 50% gas, and officials say they have taken steps to improve situational awareness when supplies are tight. 

Dive Insight:

Somerset Operating Co. this week requested the New York State Public Service Commission (PSC) waive notice requirements to shut down the plant. Once the generator is offline, New York will join a half dozen other states with no operating coal plants.

According to the Sierra Club, Idaho, Maine, Rhode Island and Vermont never had coal resources, while California and Idaho did, but subsequently retired those plants.

The filing follows new regulations and strict emissions limits finalized by the New York State Department of Environmental Conservation in May that aimed to fully eliminate coal in New York by 2020. But ISO officials say it is too soon to tell when the plant can shutter. The grid operator will still need to perform a reliability assessment, and that work has yet to begin.

"There have been a lot of different reports on Somerset," said ISO vice president of operations Wes Yeomans. "Part of the process is for us to do a reliability study first and approve their retirement ... they cannot deactivate until our reliability study is done." 

Yeomans spoke to the media Thursday to roll out the grid operator's winter reliability assessment, which found resource capacity, including generation, imports and demand response, is expected to total 43,346 MW.

Installed generation capacity amounts to 41,815 MW. Imports of 679 MW are expected to be available and demand response resources can reduce peak demand 853 MW. The ISO says it is forecasting a capacity margin of between 9,299 MW and 10,900 MW, depending on specific conditions.

Looking ahead four years, a fuel security analysis completed by Analysis Group included one scenario where downstate retirements could pose a reliability threat to that region. But NYISO officials stressed the modeling assumptions are broad and Yeomans said, "we do believe we'd be able to meet load in those situations."

In an email to Utility Dive, Yeomans said the ISO plans to monitor "all future changes in transmission developments, renewable generation additions, generator retirements, and fuel infrastructure and their potential impacts on fuel security."

New York's fuel mix leans heavily towards gas-fired units, and a full 49% of the state's capacity can run on either gas or oil. The dual-fuel capabilities allow for flexibility when temperatures spike and gas supplies are short. Another 10% of the state's capacity burns just natural gas.

"A subset of our gas generators do have firm contract supplies so they are very reliable in cold conditions," Yeomans said.

The state has been cleaning up its fuel mix and adding non-emitting resources. Nuclear and hydroelectric generation make up about a quarter of the state's generation. Wind resources supply about 4%.

Coal has been on the way out in New York for some time and was down to two plants earlier this year before the Cayuga coal plant in Tompkins County shuttered. The state is now considering a plan to convert Somerset and the Cayuga plant into data centers.

Riesling Power owns both, and in a statement said it is continuing to work with the state and other stakeholders to advance the data hub development. Riesling also said it is currently working with the New York Power Authority to procure additional power for the data hub project.

The Empire State Data Hub project "would enable us to address the governor's environmental policy goal of eliminating coal while also transitioning to a new greener economy in New York," Michael Enright, managing director of Beowulf Energy, said in a statement. The company manages the Somerset facility.

"While New York regulators assess the deactivation notice, we will continue to work with our stakeholders on a new path forward at Somerset," Enright said.

The data hub plan has "widespread and unified support from environmental, union, business and local leaders," according to a Sierra Club editorial on the issue. "Greenhouse gas emissions are significantly reduced by eliminating coal power and abandoning previous plans to repower these plants to gas," it said.

The data centers would be powered by renewable energy and battery storage built on both sites.