May 15, 2024

ISO-NE’s longer-term transmission planning changes give states new opportunities to develop policy-based transmission projects

Update, July 10, 2024: FERC accepts ISO-NE’s longer-term transmission planning changes

ISO New England has proposed new planning processes to ensure future transmission upgrades address state clean energy policies holistically and efficiently.

On May 9, the ISO filed Phase 2 of the Longer Term Transmission Planning (LTTP) tariff changes with the Federal Energy Regulatory Commission (FERC), which would create a new process to give the New England states greater control in achieving their environmental policies and goals. The new process would operate in addition to current transmission planning protocols and would enable the ISO to provide technical assistance for potential projects to help ready the region’s transmission infrastructure for the future.

The New England states have set aggressive goals for reducing carbon emissions over the next several decades, and the region will need significant transmission upgrades to ensure a reliable grid through this clean energy transition. Upgrades are needed to avoid overloading transmission lines and transformers as residents increasingly rely on electricity to heat buildings and power vehicles, and as offshore wind facilities and other renewable resources located far from population centers produce a greater share of the region’s power.

The approach outlined in LTTP Phase 2 provides a way for the states to evaluate and finance these upgrades. New steps in the evaluation process will grant the states greater insight overall, and include additional opportunities for them to provide input and request feedback as proposed projects move through the ISO’s evaluation process. As part of the planning process, the ISO will issue and evaluate requests for proposals (RFPs) to address needs identified by the states. Depending on the relative costs and benefits of the selected proposal, either the ISO or NESCOE, on behalf of a subset of the New England states, will select a transmission project for construction.

Phase 2’s cost allocation guidelines also include additional metrics for evaluating a potential transmission project. Since they help power flow from locations that are more suited to larger renewable resources (e.g., offshore wind, rural solar farms) to more densely populated areas, large transmission projects may offset the need to build new generating resources or operate existing generating resources in those densely populated areas. The new filing allows the ISO to include these cost-saving regional benefits in its evaluation process. Other new metrics encompass project costs, urgency of need, environmental impact, siting, and other factors.

LTTP Phase 2 is the culmination of a process that began in 2020 with the New England States Committee on Electricity’s (NESCOE) New England States’ Vision for a Clean, Affordable, and Reliable 21^st Century Regional Electric Grid, which called on the ISO to incorporate a longer-term transmission planning process in its system planning efforts. The first phase of the LTTP changes, accepted by FERC in February 2022, created the longer-term transmission study process, which helped initiate ISO’s landmark 2050 Transmission Study. This pioneering study outlined potential roadmaps and associated costs needed to support reliability through the clean energy transition.

Other independent system operators have adopted similar changes in longer-term transmission planning, including MISO’s Multi-Value Projects and PJM’s State Agreement Approach. Along with an extensive stakeholder engagement process, these examples helped inform the structure of the LTTP Phase 2 filing.

ISO New England has requested a response from FERC by July 9, and NESCOE has indicated a strong interest in requesting proposals related to the 2050 Transmission Study as soon as the filing is accepted.

The ISO will continue its work with the states and other stakeholders to ensure that New England’s transmission system maintains its high standard of reliability through the coming decades while meeting states’ goals for emissions reductions. In addition to advancing the work of the 2050 Transmission Study, the filing also positions the ISO to meet objectives set forth in FERC’s May 13 Grid Expansion Rule on regional transmission planning. The ISO will examine the rule and file a separate compliance proposal.