The cable that could transform New York's power grid faces setbacks

The Champlain Hudson Power Express (CHPE), the longest underground transmission line in North America, was inaugurated in May after 15 years of planning and construction that began in late 2022. It is a 339-mile (roughly 545 km) cable connecting Quebec with Queens, made up of a bundle of two high-voltage direct-current cables about five inches in diameter each, buried or submerged along the entire route—much of it beneath the bed of the Hudson River, which required special vessels capable of digging trenches by blasting pressurized jets of water at the sediment. The project, financed with private capital totaling $6 billion, is the result of a partnership between Transmission Developers (owned by asset manager Blackstone) and Hydro-Québec, the public utility that manages electricity generation and transmission in the Canadian province.

The CHPE's promise is remarkable: it could cover up to 20% of New York City's electricity demand, largely with hydroelectric power from Quebec, a province where more than 99% of electricity comes from renewable sources (mostly hydropower, though wind is growing rapidly). New York, by contrast, still relies mostly on fossil fuels despite having some hydroelectric, nuclear and wind capacity of its own. Interconnecting grids like this is seen as a way to speed up the move away from fossil fuels, since it makes it possible to move electricity to where it is needed and, according to research cited in the article, can reduce both emissions and system costs by limiting the need to build new generation capacity.

On July 3, during a heat wave, New York's power grid imported 52 gigawatt-hours of electricity from Canada, equivalent to about 9% of the state's total demand that day, and part of that flow came precisely through the CHPE. However, the line has had a rocky start: it suffered two outages. The first, on July 1, was attributed to a trip in a converter on the Canadian side of the border. The second began on July 4 and, according to the article, the line was still out of service on the morning of July 22. Officials traced the problem to a damaged section of cable on the U.S. side of the border; the manufacturer sent experts to investigate the cause, and the affected section has already been removed and replaced. According to Lynn St-Laurent, a spokesperson for Hydro-Québec, the remaining work, including post-repair testing, was estimated to be completed over the weekend (relative to the date of the article).

Some experts consulted, such as Normand Mousseau, a physics professor at the University of Montreal, note that this kind of setback is not unusual in new infrastructure projects, since the equipment is not truly put to the test until it goes into operation. The article draws a parallel with the New England Clean Energy Connect line, which connects Quebec with Maine over 145 miles and opened in January: it too has suffered outages and has provided little additional energy to the northeastern U.S. so far.

For New York, the fact that the grid did not yet depend on the CHPE turned out to be fortunate during the heat wave: according to Kevin Lanahan, a spokesperson for the New York Independent System Operator (the state's grid operator), planning studies did not assume the CHPE would be available this summer, which was precisely one of the reasons the grid operated reliably during the heat episode. A central principle of reliability planning, he noted, is not to depend on a single project. Even so, the expectation is that, as the equipment undergoes more stress testing and utilities gain confidence in the reliability of these projects, lines like the CHPE will be able to take on an increasingly larger role in the grid in the coming years, given that they represent very long-term investments.

An additional factor to watch is the state of Quebec's hydroelectric fleet: the region has suffered an intense drought over the past three years, which has depleted the water reserves used to generate electricity. This could mean that, even with the transmission lines operational, the abundant hydroelectric power needed to export across the border will not always be available, which introduces additional uncertainty about how much the CHPE will actually be able to contribute to New York's supply in the coming years.