The Northern Pass Alternatives (Part II) | Conservation Law Foundation

The Northern Pass Alternatives (Part II): Fill Up or Upgrade Existing Lines

Christophe Courchesne

Second in a series

Something that goes unmentioned in the Northern Pass project’s omnipresent (even on Christmas Day) marketing campaign is that New England already has several major transmission lines that deliver power from eastern Canada. If more imports are what New England wants, could we increase imports by filling up or upgrading these existing lines, rather than building new transmission projects like Northern Pass?

In its most recent comments to the Department of Energy (pdf), CLF insisted that the agency fully answer this question as it considers alternatives to Northern Pass in the Environmental Impact Statement for the project.

Based on available information, the answer appears to be yes, we could. As succinctly summarized in a recent white paper from the New England States Committee on Electricity, there are four major transmission lines (or “ties”) that allow for power to move from Canada to New England, and visa versa in some cases:

  • The Phase II line, a 2,000 megawatt tie that originates in far northern Québec and then crosses northeastern Vermont and the length of New Hampshire on its way to a converter station in Ayer, Massachusetts (this tie plays a big role in NH Magazine’s January 2014 feature story on Northern Pass)
  • MEPCO, a 700 megawatt tie between New Brunswick and Maine
  • NRI, a 300 megawatt tie, also between New Brunswick and Maine
  • Highgate, a 200 megawatt tie between Vermont and Québec

How do these lines provide an alternative to Northern Pass? They present two key opportunities to achieve Northern Pass’s objective of increasing imports:

Fill them up. Together, the existing ties provide 3,200 megawatts of theoretical “transfer capability.” Over the course of the year, however, not all of this capability is used. For example, the Phase II line never reaches its 2,000 megawatt capacity and instead carries 1,400 megawatts of power or less for most of the year. This chart tells the story:


The horizontal axis is hours of the year (8,760 in total), with the transfers in megawatts on the vertical axis. The blank space above the colored lines but below the horizontal line for 2,000 shows unused transfer capability. Indeed, for most of the year, the Phase II line could physically carry about 600 megawatts more than it typically does now.

Increasing power deliveries over the existing ties does present some technical challenges. In the case of the Phase II tie, what often constrains deliveries from Canada is an artificial transfer limit, imposed by the New England regional grid operator to protect system reliability, oddly enough, in the electric systems south and west of New England. It’s possible that those reliability concerns could be addressed with transmission upgrades in those systems, clearing the way for more use of the Phase II tie. In fact, New England’s grid operator is presently studying (pdf) the economic benefits of raising the Phase II transfer limit, at the request of National Grid, which operates the line and would like to see it more fully utilized.

In Maine, the transmission system south of the MEPCO and NRI ties makes it hard for some additional power that they could physically carry to reach southern New England customers, a problem afflicting new wind projects in northern Maine as well. Transmission upgrades underway or in the planning stages could help alleviate these Maine bottlenecks.

Upgrade them to carry more power. Another way to increase imports would be to improve the existing lines with more modern transmission equipment that has greater capacity. This is far from a fanciful possibility: Governor Shumlin of Vermont made headlines earlier this year when he suggested that more power could be imported over Vermont’s ties, without new transmission projects:

In light of the fact that we’re not utilizing all of our current transmission capacity, what conversations can we have with the federal government and with ISO New England about increasing the load in our existing infrastructure before we get panicked about building new?  Vermont Governor Peter Shumlin 

As we think about upgrades, or the technical fixes that may be required to fill the existing lines to full capacity, we should be mindful that the full extent of the costly changes to New England’s transmission system to accommodate Northern Pass is not yet known. This uncertainty played a key role in the Reliability Committee of the New England Power Pool refusing to endorse at its December meeting Northern Pass’s request, already three years in making, that the New England regional grid operator make a finding that the project will not have a significant adverse effect on the transmission system’s reliability.

The promise of the opportunities to make better use of our existing transmission system, especially when taken together, is that they could very efficiently enable new imports in amounts approaching what Northern Pass would provide, but without the significant impacts or costs of major new transmission projects. Fully using our existing transmission system could be a logical and practical approach to new imports; in the Northern Pass permitting process and elsewhere, regional stakeholders should carefully and thoroughly consider it.

Read the introduction to and first post in this series: The Northern Pass Alternatives (Part I): Going Underground. All posts in the series can be found here.

Learn more about Northern Pass here or by signing up for CLF’s email newsletter, Northern Pass Wire. For the latest Northern Pass updates,  follow me on Twitter.

Focus Areas

Climate Change


New Hampshire


Northern Pass

About the CLF Blog

The views and opinions expressed on this blog do not necessarily represent the opinions or positions of Conservation Law Foundation, our boards, or our supporters.