Timing of CHPE Transmission Project Vital to Future Grid Reliability
As the transition to renewable energy accelerates in New York, we must monitor several factors to understand the impacts of this monumental change on electric system reliability. One of the biggest items to watch is progress with the Champlain Hudson Power Express (CHPE) transmission facility, and the impact the project could have on declining reliability margins in New York City.
We recently released our Reliability Needs Assessment (RNA), an in-depth study which evaluates the reliability of the New York bulk electric grid for the next 10 years. In evaluating reliability, the study considers forecasts of peak power demand, planned upgrades to the transmission system, and changes to the generation mix.
Using computer modeling of present and future electric resources and transmission capacities, the RNA found thinning reliability margins across New York.
Risk factors that could cause near-term reliability challenges include:
- Greater-than-forecasted electricity demand
- Extreme weather such as heatwaves
- Delays in planned transmission and generation projects, most notably the approved Champlain Hudson Power Express project, scheduled to be in service in the spring of 2026
- Potential for additional generator deactivations or unplanned outages
The RNA found that New York City faces the greatest risk, with reliability margins projected to be just 50 MW in 2025, equal to less than 1% of the forecasted New York City peak demand.
A reliability margin refers to the extra generation capacity and transmission capability that’s available above peak demand, the period when electricity use is at its highest. It’s vital for reliability to retain a level of excess capability to keep the system reliable during high-demand periods in the event of unplanned generator or transmission outages.
The risks in New York City are due to limited generation and transmission capability. In the case of generation, retirements of peaker plants pursuant to new emissions rules by the New York State Department of Environmental Conservation (DEC Peaker Rule) will reduce available resources for additional electricity at times of high demand.
A major risk factor identified in the RNA is a delay in the completion of CHPE, a 339-mile underground cable that will deliver 1,250 megawatts (MW) of emissions-free electricity from Hydro-Quebec to New York City.
The two, five-inch-diameter cables will be buried under Lake Champlain, the Hudson River, and some highway rights-of-way. According to the project developer, the project is scheduled to come online in mid-2026. As New York State moves to decarbonize the power grid, CHPE will serve as a valuable source of clean energy by bringing electricity directly to New York City.
CHPE will also provide a vital contribution to the reliability margins that are tightening over time. Over the 10-year RNA study period, the margins fluctuate with changing projects and conditions. By the time CHPE comes online, New York City could have a reliability margin of just 50 MW (less than 1%), an extremely low figure for the densest population area of the entire state.
Even with CHPE scheduled to begin operation in 2026, the margin increases substantially, but narrows again to about 100 MW by 2032 due to increases in demand. Without CHPE, in only a few years margins would be such that there will be more electricity demand on peak days than what the grid can provide, our models showed.
These findings underscore the importance of CHPE entering into operation on schedule in order to avoid reliability problems in New York City and elsewhere.
Additional potential risk factors include increased demand or additional generators going off-line. Also, significant heat waves or violent storms could result in such deficits, even with CHPE in place.
In these scenarios, some generation affected by the DEC Peaker Rule may need to remain in service until permanent solutions are developed, in order to maintain a reliable grid.
For more about potential impacts to New York's evolving power grid and scenarios modeled in our Reliability Needs Assessment, download the report.
Download our key takeaways datasheet.