DEEP’s preliminary Clean Energy Pathways model results indicate possibility for clean-energy curtailments in scenarios with high renewables penetration in Northern New England and SEMA/RI in conjunction with retirement of Millstone; Comments due by July 2

On June 18, 2020, the Department of Energy and Environmental Protection (DEEP) and its consultant Levitan and Associates, Inc. (Levitan) held a technical meeting during which Levitan presented the preliminary model results for the Clean Energy Pathways Analysis, which is part of DEEP’s 2018 Integrated Resources Planning (IRP) proceeding. The slides from the technical meeting are located here.

As discussed in Digest 77, DEEP updated the IRP scope in response to legislative changes and Governor Ned Lamont’s (D) September 2019 Executive Order Number 3. The September 2019 Executive Order directed DEEP to analyze pathways and recommend strategies for achieving a 100% zero-carbon target for the electric sector by 2040 in the 2018 IRP.

In the technical session, Levitan presented preliminary model results for four scenarios of alternative beneficial electrification and decarbonization outlook:

The analysis examined the regional resource build-out for each scenario in the context of Connecticut’s 100% zero-carbon target. It also evaluated the reliability of each portfolio mix, as well as concerns (such as increased operating reserves) related to high variable energy resource (VER) penetration. Lastly, the analysis compared the costs and benefits of each scenario to a Reference Scenario based on current mandated electric sector goals (the statutory GHG emission reduction targets are currently a 45% reduction in emissions below 2001 levels by 2030 and 80% reduction by 2050, under Public Act 18-82 and Global Warming Solutions Act).

As shown in the graph below, increasing the state’s beneficial electrification of transportation and heating load (Electrification Reference Scenario) would result in 4GW additional resource additions (including additional battery storage, offshore, and some energy efficiency and grid-scale solar) to the region and marginally more (0.5GW) retirement when compared to the Reference Scenario. If a boost in beneficial electrification is combined with meeting the 100% zero-carbon target (Electrification Balance Blend Scenario), resource additions and retirement would increase by 18GW and 2.5GW respectively. Resource additions are primarily attributable to offshore wind, battery storage, and grid-scale solar.

The analysis concluded that increasing beneficial electrification alone would not lead to material clean energy curtailments. However, under the decarbonization scenarios, the analysis observed that addition of land-based wind and solar resources in Northern New England, the retirement of Millstone, saturation of offshore wind projects in SEMA/RI, and resultant interface constraints would coincide with increased clean energy curtailment. In addition, the analysis indicated wholesale energy price declines would occur in the decarbonization scenarios as a result of high penetrations of variable cost resources.

DEEP is soliciting comments on the model results. Written comments are due on July 2 by 4:00 pm and should be submitted to DEEP’s website or emailed to

In addition, after reviewing stakeholder comments on initial model scenarios, DEEP will study the following model scenarios (listed verbatim):

  • Carbon Pricing: Impose a carbon price on generators located in Connecticut.
  • Transmission: Remove transmission constraints imposed in the Balanced Blend case.
  • Behind the Meter Solar Emphasis: Substitute a portion of grid-scale solar selected in the Balanced Blend case with behind the meter solar.
  • Millstone PPA Extension: Extend the commercial operation of Millstone Units 2 and 3 through 2040.

Finally, DEEP has released the following revised schedule for the release of various sections contained in the IRP (listed verbatim):

  • Base Case and Balanced Blend (Economically Optimal) Model Run Results Release:
    • Technical Meeting – June 18, 2020
    • Written Comments deadline – July 2, 2020
  • Policy Assessment of Deregulation:
    • Draft release – No later than August 2020
    • Technical meeting and public hearing – no later than September 2020
    • Written Comments deadline – No later than October 2020
  • Thermal Renewable Portfolio Standard Discussion Draft:
    • Draft release – no later than August 2020
    • Technical meeting – no later than September 2020
    • Written Comments deadline – no later than October 2020
  • Release remaining Clean Energy Pathways Analysis and Recommendations:
    • Draft Release – August 2020
    • Public Hearing and Technical Meeting – September 2020
    • Written Comments deadline – October 2020
    • Release consolidated Final IRP – Winter 2020