Low-to-Moderate Income Emissions Reductions in Massachusetts: A Marginal Cost of Abatement Analysis

Client: Green Energy Consumers Alliance (GECA)

Authors: Sagal Alisalad, Joshua R. Castigliego, Liz Stanton, PhD

May 2026

On behalf of Green Energy Consumers Alliance (GECA), Researcher Sagal Alisalad, Senior Researcher Joshua R. Castigliego, and Principal Economist Liz Stanton, PhD, prepared a report analyzing the costs of low-to-moderate income (LMI) emissions reductions measures in Massachusetts. AEC staff assessed LMI-specific emissions reduction measures that could be implemented in Massachusetts by 2030 and developed a marginal abatement cost curve showing eight measures from lowest to highest cost. AEC’s analysis found that the eight measures would reduce emissions by 0.2 million metric tons (MMT) in 2030, about 7 percent of the 2.9 MMT needed to meet the Commonwealth’s 2030 climate targets, and that the eight measures total 2.8 MMT of lifetime CO2e reductions and have a net societal benefit, or cost savings, of $7.3 billion.

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Electrification with Equity, Part 2: Scaling Behind-the Meter Solar and Storage in Massachusetts Environmental Justice Communities

Clients: Clean Energy Group, Union of Concerned Scientists, and Vote Solar

Authors: Tanya Stasio, PhD and Elisabeth Seliga

May 2026

Massachusetts electric demand is expected to increase substantially by 2050, creating the need for additional electric generating capacity. Deployment of on-site or behind-the-meter (BTM) solar and BTM solar paired with storage in allows customers to generate and store their own clean energy, which in turn can lower peak electric demand, reduce the need for additional investments in expensive gas-fired power plants, and provide households and businesses with energy bill savings, increased resilience, and energy autonomy. Increasing BTM deployment in the Commonwealth’s low-income and environmental justice neighborhoods, will advance its commitment to an equitable clean energy transition and direct clean energy and storage benefits where its needed most.

On behalf of Clean Energy Group, Union of Concerned Scientists, and Vote Solar, AEC Senior Researcher Tanya Stasio, PhD and Assistance Researcher Elisabeth Seliga prepared a report that estimates the technical potential for BTM solar paired with storage in Massachusetts environmental justice neighborhoods using solar technical potential estimates from the 2023 Massachusetts Department of Energy Resources’ Technical Potential of Solar Study. In addition, this report, through original analysis and input from an environmental justice advisory committee, identifies nine primary barriers to solar and storage adoption and advances 18 recommendations to address these barriers and help realize BTM solar and storage potential in Massachusetts’ environmental justice neighborhoods. In Electrification with Equity, Part 1, linked below, AEC estimates Massachusetts statewide “highly suitable” technical potential for BTM solar paired with storage.

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Link to Electrification with Equity, Part 1 Report

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Electrification with Equity, Part 1: The Opportunity for Behind-the-Meter Solar and Storage in Massachusetts

Clients: Clean Energy Group and Vote Solar

Authors: Tanya Stasio, PhD, Elizabeth A. Stanton, PhD and Joshua R. Castigliego

May 2026

Massachusetts electric demand is expected to increase substantially by 2050, creating the need for additional electric generating capacity. Behind-the-meter (BTM) solar and solar paired with storage resources provide an opportunity for meeting this demand while reducing energy bills for customers, increasing renewable energy integration, and improving grid resiliency. On behalf of the Clean Energy Group and Vote Solar, AEC Senior Researcher Tanya Stasio, PhD, Principal Economist Elizabeth A. Stanton, PhD, and Senior Researcher Joshua R. Castigliego prepared a report that estimates the technical potential for BTM solar and solar paired with storage and the opportunity for these distributed energy resources to reduce expected increases in Massachusetts’ peak electric demand.

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Link to Electrification with Equity, Part 2 Report

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Savings from Coal to Gas Conversion: Florida’s Northside 1 and 2

Client: Sierra Club

Author: Liz Stanton, PhD, Joshua R. Castigliego, Jordan Burt, PhD, and Bryndis Woods, PhD

April 2026

AEC-2026-04-WP-01

On behalf of Sierra Club, Principal Economist Elizabeth A. Stanton, PhD, Senior Researcher Joshua R. Castigliego, Researcher Jordan Burt, PhD, and Principal Analyst Bryndis Woods, PhD, prepared a white paper that investigates the potential cost savings associated with transitioning JEA’s Northside Generation Station to retire its coal-fired operations and run exclusively on natural gas. Using a simple model of annual expenses and revenues at the unit for the period 2026 to 2035, AEC compared net costs under a “business-as-usual” scenario in which the operations of recent historical years continue into the future with a “gas conversion” scenario in which full-time gas operations commence in 2030. Over the 10-year modeling period, elimination of all coal operations at Northside Units 1 and 2 result in a total savings of $122.8 million, or $51.9 million at Northside Unit 1 and $70.9 million at Unit 2. Northside Unit 1’s levelized costs fall by $11.4 per MWh and Unit 2’s by $8.5 per MWh.

A cost savings opportunity of this magnitude—approximately 12 percent reduction from current Northside 1 and 2 costs—deserves careful and transparent examination. Utility decisions regarding capital investments, maintaining aging infrastructure, and day-to-day operations must consider affordability and keep an open mind to new options for lowering costs. To achieve a successful conversion at Northside Units 1 and 2, AEC recommends that JEA conduct and publicly share a comparative analysis of its future operations (including all fixed, variable, and capital costs and financing) under current mixed fuel operations and under all gas operations. All assumptions, data, and methodologies should be fully transparent and made publicly available, and JEA’s analysis should also assess the conversion’s impact on rates and customer bills.

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Savings from Coal to Gas Conversion: Florida’s Deerhaven 2

Client: Sierra Club

Author: Liz Stanton, PhD, Joshua R. Castigliego, Jordan Burt, PhD, and Bryndis Woods, PhD

April 2026

AEC-2026-04-WP-02

On behalf of Sierra Club, Principal Economist Elizabeth A. Stanton, PhD, Senior Researcher Joshua R. Castigliego, Researcher Jordan Burt, PhD, and Principal Analyst Bryndis Woods, PhD, prepared a white paper that investigates the potential cost savings associated with transitioning Gainesville Regional Utilities’ (GRU) Deerhaven Generation Station to retire its coal-fired operations and run exclusively on natural gas. Using a simple model of annual expenses and revenues at the unit for the period 2026 to 2035, AEC compared net costs under a “business-as-usual” scenario in which the operations of recent historical years continue into the future with a “gas conversion” scenario in which full-time gas operations commence in 2030. Over the 10-year modeling period, elimination of all coal operations at Deerhaven Unit 2 results in a total savings $31.3 million (or a reduction in levelized costs of $7.4 per MWh).

A cost savings opportunity of this magnitude—approximately a 7 percent reduction from current Deerhaven Unit 2 costs—deserves careful and transparent examination. Utility decisions regarding capital investments, maintaining aging infrastructure, and day-to-day operations must consider affordability and keep an open mind to new options for lowering costs. To achieve a successful conversion at Deerhaven Unit 2, AEC recommends that GRU conduct and publicly share a comparative analysis of its future operations (including all fixed, variable, and capital costs and financing) under current mixed fuel operations and under all gas operations. All assumptions, data, and methodologies should be fully transparent and made publicly available, and GRU’s analysis should also assess the conversion’s impact on rates and customer bills.

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Rhode Island Heat Pump Rate “RI Test” Report

Client: Conservation Law Foundation and Environmental Defense

Author: Elizabeth A. Stanton, PhD, Joshua R. Castigliego, and Jordan Burt, PhD

April 2026

On behalf of Conservation Law Foundation and Environmental Defense, Principal Economist Elizabeth A. Stanton, PhD, Senior Researcher Joshua R. Castigliego, and Researcher Jordan Burt, PhD, prepared a report assessing the results of a “Rhode Island Benefit Cost Test” (RI Test) cost-benefit analysis comparing the monetized costs and benefits of a new heat pump electric rate proposed in Rhode Island Public Utility Commission Docket No. 25-45-GE.

AEC found that the net impact of a heat pump rate is a system-wide cost savings of $11.9 million, or benefit to cost ratio of 1.3. The proposed residential heat pump rate shows greater benefits than costs under the RI Test methodology.

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Testimony on the Proposed Rhode Island Residential Heat Pump Rate

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Testimony on the Proposed Rhode Island Residential Heat Pump Rate

Client: Conservation Law Foundation and Environmental Defense

Author: Elizabeth A. Stanton, PhD 

April 2026

On behalf of the Conservation Law Foundation and Environmental Defense, Principal Economist Elizabeth A. Stanton, PhD, submitted direct testimony before the Rhode Island Public Utilities Commission describing the methodology and results of the benefit-cost analysis “RI Test” performed on the proposed Rhode Island residential heat pump in Docket No. 25-45-GE. Dr. Stanton found that the net impact of a heat pump rate is a system-wide cost savings of $11.9 million, or benefit to cost ratio of 1.3. The proposed residential heat pump rate shows greater benefits than costs under the RI Test methodology.

Link to Direct Testimony

Rhode Island Heat Pump Rate “RI Test” Report

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Comments Regarding STREAM’s Proposed Data Center

Client: Tonawanda Seneca Nation and Sierra Club Niagara Group

Author: Bryndis Woods, PhD 

April 2026

In January 2026, STREAM U.S. Data Centers, LLC (STREAM) applied to the Genesee County Economic Development Center to construct a 2.2 million square-foot data center campus in the Town of Alabama, New York, located in Genesee County. On behalf of Tonawanda Seneca Nation and Sierra Club Niagara Group, Senior Analyst Dr. Bryndis Woods drafted comments that address STREAM’s proposed data center, including its claimed costs and benefits for the local community. STREAM does not provide any supporting materials for its cost-benefit analysis (CBA), which fails to meet standards expected in a public decision-making process and is insufficient to determine whether the proposed project would provide net benefits for the local community.

Other key findings include:

• The project would require electric capacity that is about four times the total capacity currently operating in Genesee County.

• STREAM’s CBA results differ substantially from one CBA to the next.

• STREAM has failed to address numerous potential costs associated with the project.

• STREAM’s job creation estimates exceed values found in publicly available data and information.

• STREAM has requested tax abatements that are worth 25 times more than the benefits provided by the proposed PILOT/Host payments.

• Valuing data centers is challenging and complex.

• STREAM’s proposed data center may negatively impact local tourism and recreation, which are an integral part of the community and economy.

Errata:

On page 12 of the comments, it states that: "Empire State Development of New York State’s 2024 Tourism Economics Report found that, in Genesee County, visitors spent $144.5 million in 2024, generating about $331.1 million in direct personal income for county residents, creating about 11,000 direct jobs and about 5,000 indirect jobs, and generating $8.8 million in local tax revenue—equal to $665 in tax savings per household." This should read: "Empire State Development of New York State’s 2024 Tourism Economics Report found that, in Genesee County, visitors spent $144.5 million in 2024, generating about $46.8 million in direct personal income for county residents, creating 1,850 direct jobs and generating $8.8 million in local tax revenue—equal to $665 in tax savings per household." 

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Background Report: Evaluation of Connecticut Medical Protections

Client: Connecticut Public Utilities Regulatory Authority

Authors: Tanya Stasio, PhD, Sagal Alisalad, Elizabeth A. Stanton, PhD, Jordan Burt, PhD, Joshua R. Castigliego, and Bryndis Woods, PhD 

March 2026

On behalf of Connecticut Public Utilities Regulatory Authority, Senior Researcher Tanya Stasio, PhD, Researcher Sagal Alisalad, Principal Economist Liz Stanton, PhD, and AEC staff prepared a background report that evaluates Connecticut's electric and gas utility shutoff policies for medically protected customers. Most of Connecticut's medically protected customers have year-round shutoff protection and, as a result, maintain average arrearages that are thousands of dollars more than customers without medical protections. While limiting shutoff protections may increase utility revenues and reduce ratepayer costs, AEC finds that introducing payment or financial hardship requirements to Connecticut shutoff protections for medically protected customers could cost the State of Connecticut millions by way of increased need for social services. 

This report was included as an Appendix to Connecticut Public Utilities Regulatory Authority's Report to the General Assembly Regarding the Evaluation of Medical Protection available here.

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Assessing Ratepayer Risks of the Proposed Edisto Gas Plant in South Carolina

Client: Conservation Voters of South Carolina (CVSC)

Authors: Joshua R. Castigliego, Elisabeth Seliga, Jordan Burt, PhD, Sagal Alisalad, and Bryndis Woods, PhD

March 2026

On behalf of the Conservation Voters of South Carolina (CVSC), Senior Researcher Joshua R. Castigliego, Assistant Researcher Elisabeth Seliga, Researchers Jordan Burt, PhD and Sagal Alisalad, and Principal Analyst Bryndis Woods, PhD prepared a report that evaluates Santee Cooper and Dominion Energy South Carolina’s December 2025 Joint Application to build a new jointly owned, 2,180-MW natural gas-fired combined cycle generating facility—the proposed “Edisto Gas Plant” or Canadys Joint Resource—on the banks of the Edisto River. The report examines the risks that the project could pose to South Carolina ratepayers if approved by the South Carolina Public Service Commission.

In the report, AEC identifies three primary risks to ratepayers (i.e. the potential for electric customers to face higher costs) as a result of new gas-fired capacity like the proposed Edisto Gas Plant to meet increasing electric demand: (1) uncertain forecasts of customer demand, which could leave ratepayers paying for unused capacity; (2) higher-than-expected capital costs, including from construction delays and cost overruns; and (3) fuel price uncertainty, which can increase operating expenses and, ultimately, electric rates and customer bills. AEC's review of the Companies’ Joint Application reveals several significant concerns related to these risks.

Understanding risks to South Carolina ratepayers, individually and collectively, underscores the importance of prudent utility planning and the need for the Commission to carefully consider whether approving the Companies’ Joint Application for the proposed Edisto Gas Plant would expose ratepayers to unnecessary risk, particularly when alternative, lower-risk pathways may exist that the Companies have not fully evaluated.

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Testimony on Southwestern Public Service Company's (SPS) Application to Construct New Generation Facilities

Client: Sierra Club

Authors: Bryndis Woods, PhD

February 2026

On behalf of Sierra Club, Principal Analyst Dr. Bryndis Woods filed testimony before the Texas Public Utility Commission regarding SPS's Application to amend its Certificate of Convenience and Necessity (CCN) to construct eight new generation facilities totaling over 4,100 megawatts in Texas and New Mexico. 

Dr. Woods' direct testimony evaluates three issues in SPS’s Application: 1) the claim that additional generating capacity is needed to serve large-load interconnection requests; 2) the Company's approach to pursuing solar and wind resources; and 3) the potential impacts of the forthcoming expansion of SPS’s regional grid operator, Southwest Power Pool (SPP). Dr. Woods' recommendations included that the Commission require SPS: include only contractually committed new loads in its base load forecast; establish consumer protections for new large loads; utilize available surplus interconnection capacity to develop additional wind and solar projects; and assess the potential impacts of SPP's expansion.

Dr. Woods' cross-rebuttal testimony focused on additional issues in the proceeding, including that: SPS's Island Case modeling should not be used to make determinations regarding resource reliability; battery storage projects contribute significantly to grid reliability during extreme winter weather events; new gas pipeline capacity in the Permian Basin favors retirement of coal-fired units at the Tolk plant; and any extension of Tolk's coal-fired units would entail significant costs. 

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Link to Cross-Rebuttal Testimony

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Risks of New Gas-Fired Generation in Arizona

Client: Western Resource Advocates (WRA)

Authors: Bryndis Woods, PhD, Elisabeth Seliga, Alicia Zhang, Brady Dye, and Elizabeth A. Stanton, PhD

February 2026

On behalf of Western Resource Advocates (WRA), a new AEC report assesses the risks associated with new gas-fired electric generation in Arizona.

The report finds that Arizona’s electric sector is dominated by gas-fired resources and much more gas-fired capacity is currently proposed. Arizona’s utilities claim that new gas-fired generation is needed to address reliability challenges and meet anticipated growth in electric demand. However, the report finds that building new gas-fired generation hurts reliability and exposes Arizona’s residents and ratepayers to six serious risks: 1) More gas generation means higher electric bills; 2) Overreliance on gas-fired generation; 3) High electric bills due to high gas prices; 4) Gas pipelines and storage constraints; 5) Growing electric demand; and 6) Human health and safety impacts.

The report concludes that, rather than furthering reliance on gas, Arizona’s utilities should instead prioritize resources that stand to benefit the state’s residents and ratepayers. Solar, wind, battery storage, energy efficiency, and demand-side management resources lower costs, diversify Arizona’s energy mix, are not reliant on fuel supply, and reduce pollution.

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Evaluating Load Management Strategies for a Net Zero Grid in Massachusetts

Client: Massachusetts Department of Energy Resources (DOER)

Authors: Bryndis Woods, PhD and Tanya Stasio, PhD

December 2025

On behalf of the Massachusetts Department of Energy Resources (DOER), Principal Analyst Bryndis Woods, PhD and Senior Researcher Tanya Stasio, PhD contributed to an assessment of load management potential in Massachusetts in futures aligned with deep decarbonization and the Commonwealth’s Climate and Clean Energy Plan (CECP) goals. The assessment was led by Energy + Environmental Economics (E3) and AEC supported by leading the development of resiliency and equity impacts of load management resource deployment and managing the advisory group and stakeholder sessions.

AEC managed a total of four advisory group meetings and two public stakeholder workshops between May and September 2025. AEC's analysis included the development of a Social Vulnerability Index (SVI) that identified disadvantaged communities in Massachusetts by assessing their vulnerability across ten measures (e.g. income, race/ethnicity, energy burden). We find that mindful design of programs to support load management strategies can improve outcomes for disadvantaged communities (e.g. reduced energy burden, reduced outages).

Link to Report

Link to DOER Project Webpage

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Lower Heating Costs with Thermal Networks

Client: Green Energy Consumers Alliance (GECA) and Black Swan Lab

Authors: Sagal Alisalad and Joshua R. Castigliego

December 2025

On behalf of Green Energy Consumers Alliance (GECA) and Black Swan Lab, Researcher Sagal Alisalad and Senior Researcher Joshua R. Castigliego prepared a white paper analyzing the near-term operational costs of heating for an average Massachusetts household using thermal energy networks compared to gas furnaces. AEC examined two seasonal heat pump rate scenarios for thermal energy networks with a range of efficiency levels from a coefficient of performance (COP) between 6 and 8: (1) HP 1.0: Massachusetts Department of Public Utilities (DPU)-approved seasonal heat pump rates, and (2) HP 2.0: Massachusetts Department of Energy Resources (DOER)-proposed seasonal heat pump rates. The analysis highlights thermal energy networks as the far more cost-effective and energy-efficient choice for an average-sized, average-energy-use household.

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GreenRoots’ Pathway to Interconnection

Client: GreenRoots

Authors: Sagal Alisalad and Bryndís Woods, PhD

November 2025

On behalf of GreenRoots, Researcher Sagal Alisalad and Principal Analyst Bryndís Woods, PhD, prepared a report summarizing GreenRoots’ experience applying to interconnect three behind-the-meter (BTM) projects to the electric grid: 1) Chelsea City Hall (solar and storage), 2) Chelsea Police Department (solar and storage), and 3) Municipal Public Works Yard (rooftop solar). AEC examined the obstacles and complexities of the interconnection process for small- and medium-sized customers like GreenRoots. This analysis highlights how these barriers hinder a community’s ability to develop community-owned BTM resources.

AEC recommends that decision-makers, utilities, and communities collaborate to address barriers to interconnection in order to boost community resiliency, support the clean energy transition, help the Commonwealth reach its clean energy and emission reduction goals, and ensure energy systems in the Commonwealth benefit everyone.

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Consumers Energy 2025 Rate Case

Client: Michigan Environmental Council and Citizens Utility Board of Michigan

Authors: Tyler Comings

November 2025

Principal Economist Tyler Comings filed testimony before the Michigan Public Service Commission on the Consumers Energy 2025 rate case, on behalf of Michigan Environmental Council and Citizens Utility Board of Michigan. Mr. Comings addressed the risks of further gas investment given the pressure on prices from LNG exports. He also recommended disallowance of two capital projects at the Jackson gas plant due to flaws and lack of support in the company's economic assessments for those projects. 

Link to Testimony

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Testimony on Entergy Arkansas’ Request for a Certificate of Environmental Compatibility and Public Need

Client: Arkansas Electric Energy Consumers, Inc. (AEEC)

Authors: Liz Stanton, PhD

September 2025

On behalf of Arkansas Electric Energy Consumers, Inc. (AEEC), Principal Economist Elizabeth A. Stanton, PhD submitted direct testimony before the Arkansas Public Service Commission to assess Entergy Arkansas, LLC’s request for a Certificate of Environmental Compatibility and Public Need (“CECPN”) and a Certificate of Convenience and Necessity (“CCN”) in Docket No. 25-047-U. In this case, the Company requests approval for the construction and operation of Jefferson Power Station, a 754-megawatt gas-fired combined cycle combustion turbine (“CCCT”) at its existing White Bluff site. In her testimony, Dr. Stanton reviews the Company’s need for additional generation resources, its evaluation of alternative supply-side resource options, and the adequacy of its recent request for proposal (“RFP”) process.

Dr. Stanton recommends that the Commission reject the application for a CECPN as incomplete and require Entergy Arkansas to: reapply with all the information necessary to provide clear evidence that it requires additional capacity and/or generation at this time, and that the Jefferson Power Station represents the least-cost option; provide supplemental materials supporting the need for the project; conduct an all-resource RFP and make its results available to stakeholders; present cost and feasibility comparisons of resources not sited at White Bluff and resources other than natural gas-fired combined cycle combustion turbines. She also recommends that the Commission request that the Arkansas State Legislature reconsider its imposition of a six-month timeframe for CECPN cases.

Link to Testimony

Link to Surrebuttal

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Xcel Colorado Resource Plan Testimony

Client: Sierra Club and Natural Resources Defense Council (NRDC)

Authors: Tyler Comings

September 2025

Principal Economist Tyler Comings provided testimony before the Colorado Public Utilities Commission on resource plan modeling done by Public Service Company (or Xcel Colorado). Mr. Comings found that the utility should make many changes to its modeling methodology including allowing market access, justifying that new gas resources will be carbon-free, and correctly discounting social costs of carbon and methane. 

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Duke Indiana Resource Plan Comments

Client: Sierra Club

Authors: Tyler Comings, Joshua R. Castigliego, and Jordan Burt, PhD

September 2025

Principal Economist Tyler Comings, Senior Researcher Joshua Castigliego, and Researcher Jordan Burt, PhD, co-wrote comments on the Duke Energy Indiana 2024 Integrated Resource Plan (IRP) with Sierra Club. The comments argue that Duke should have chosen a different preferred plan that was lower-cost and lower-risk--a portfolio with a lower gas buildout and that converted the Edwardsport coal plant to natural gas as soon as feasible.

Link to Comments

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Ameren Missouri Rate Case Testimony

Client: Sierra Club

Authors: Tyler Comings

September 2025

Principal Economist Tyler Comings provided testimony before the Missouri Public Service Commission on the utility's proposed return on equity (ROE) and economics of its coal units. Mr. Comings found that the utility's proposed ROE of 10.25 percent was too high, finding that using more reasonable assumptions and methods would lead to an ROE between 9.25 and 9.5 percent. He also argued that the Sioux coal units were costly and unreliable which should lead Ameren to consider their earlier retirement. 

Link to Direct Testimony

Link to Surrebuttal Testimony

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