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Regional transmission investment: Spring 2018 update

768 projects put into service since 2002 to fortify New England’s transmission system

The ISO recently published the March 2018 update to the Regional System Plan (RSP) Project List, which details Pool Transmission Facility (PTF) projects needed to ensure reliability in New England. Since the October 2017 update, 22 upgrades were placed in service and no new projects were added. Since 2002, a cumulative total of 768 project components representing an investment of $10.4 billion have been placed into service to help ensure that New England’s transmission system continues to reliably and efficiently move wholesale electricity across the region.

About the RSP Project List

Published three times a year (March, June, and October), the RSP Project List describes the status of regional transmission reliability projects. As a part of the regional system planning process, the ISO must continually:

  • Re-assess the timing and components of existing projects to accommodate forecasted changes in net loads, the retirement of generating resources, and the addition or delay of new power resources
  • Study the ability of the New England transmission system to meet federally-mandated reliability requirements and adequately serve the region

Note: The RSP Project List format was updated in May 2015 to indicate which transmission upgrades on the list are “grandfathered” and which are not, with respect to new requirements under Order No. 1000, Transmission Planning and Cost Allocation, from the Federal Energy Regulatory Commission. The new processes will not apply to proposed or planned projects on the list prior to May 18, 2015, unless the ISO must reevaluate the solution design. (Concept projects aren’t grandfathered.) See the May 18, 2015 update for more.

As of March 2018, the update presentation lists 98 active projects across all six New England states. This includes:

  • 38 projects under construction
  • 38 planned projects
  • 22 proposed projects

The estimated cost of active future projects through 2021 is under $2.0 billion.


In addition to helping ensure the region can count on the electricity it needs every minute of every day, transmission system upgrades also help lower wholesale electricity costs and enable the development and use of cleaner energy resources. Improving the movement of electricity across the region and into areas of limited transmission and high demand:

  • Allows more competition among generators, reduces congestion charges in the energy market, reduces the need for expensive generator reliability agreements, and reduces out-of-market generator dispatch payments
  • Allows older, more expensive generators to retire, making way for cleaner, more efficient, less expensive resources

Tempering factors

Regional energy trends can affect transmission needs. For example, the New England states are national leaders in energy-efficiency (EE) policies and programs. EE savings—when coupled with new generators and other transmission upgrades—may allow the region to defer certain transmission projects deemed necessary to address reliability needs.

With their continued expansion, solar photovoltaic (PV) resources and other forms of distributed generation may also one day be able to alleviate or prevent constraints in regional power system transmission or distribution, and reduce or eliminate the need to install new transmission or distribution facilities.

Additionally, market resource alternatives (MRAs)—such as new generators or demand-response resources—may in some cases be able to help alleviate transmission needs. The ISO has performed MRA analysis on select portions of the system to help signal to developers and stakeholders where these opportunities exist.

Learn more