A 339-mile transmission line from Canada to NYC will help but not cure the U.S.'s most populous city's shrinking demand margins.

A report released at the end of November by the New York Independent System Operator raised concerns over New York's plans to retire fossil fuel plants and electrify buildings while the state faces growing demand issues. The organization said the state could see reliability margins narrowing to "concerning levels as early as 2023." 

A new transmission line now underway may help. The same day that report was released, New York Gov. Kathy Hochul announced that construction of the Champlain Hudson Power Express transmission line was underway, a 339-mile underground transmission line that will deliver 1,250 megawatts of Canadian hydropower to New York City. The $6 billion project is expected to be completed by 2026.  

The new transmission line will help bridge a summer reliability gap over the next ten years, the NYISO report said; however, it will not provide any power during the winter months. As the nation saw over the Christmas holiday, winter reliability may be a more critical issue to address as the nation braces for potentially more intense winter storms.  A press release attached to the NYISO report says New York City's reliability margins may not be enough if the Champlain Hudson project experiences delays, if New York City demand increases by even 60MW or if there are additional generator deactivations beyond what is already planned. 

Even with a major transmission line going in, extreme weather still poses the greatest threats to the state's grid reliability. Winter Storm Elliot, which killed more than 50 people over the Christmas holiday and triggered rolling blackouts for millions across the country, occurred during a winter forecasted to be mild. While these massive transmission lines are going to help, utilities and power providers would do well by their customers to retune their weather forecasts and planning to include the growing possibility of more extreme events.