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.

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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.

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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.

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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.

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Accounting for Indirect Fiscal Impacts in Connecticut’s Legislative Review

Client: Connecticut Roundtable on Climate and Jobs (CRCJ)

Authors: Jordan Burt, PhD, Elisabeth Seliga, and Joshua R. Castigliego

August 2025

On behalf of the Connecticut Roundtable on Climate and Jobs (CRCJ), Researcher Jordan Burt, PhD, Assistant Researcher Elisabeth Seliga, and Senior Researcher Joshua R. Castigliego prepared a policy brief that evaluates the use of fiscal notes in Connecticut’s legislative review process and identifies the key limitations in capturing the full extent of a bill’s impact in Connecticut. Fiscal notes summarize the expected impacts on government revenues and expenditures, helping lawmakers evaluate a bill’s impact on government budgets. To best inform decision-making, fiscal notes must accurately reflect the true cost of legislation. In Connecticut, fiscal notes exclude indirect fiscal impacts. The result is a misestimation of a bill’s effect on the state’s budget that can result in beneficial proposals being rejected or flawed legislation being passed. As a first step toward improving the accuracy of fiscal notes, AEC recommends that Connecticut adopt “enhanced fiscal notes” that incorporate both direct and indirect fiscal costs to provide a more complete picture of a bill’s fiscal consequences during the legislative review process.

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Amicus Curiae in the Case of Genesis B. v. United States Environmental Protection Agency

Author: Liz Stanton, PhD

July 2025

Principal Economist Elizabeth A. Stanton led AEC Staff in drafting an amicus curiae brief submitted on appeal from the United States District Court for the Central District of California, No. 2:23-cv-10345, in the case of Genesis B. v. United States Environmental Protection Agency (EPA). The Genesis plaintiffs (a group of 18 youths) argued that the EPA violated their right to equal protection of the law through discriminatory discounting of children’s lives when making environmental decisions.

In the brief, the amici curiae contend that discounting practices used by the EPA are detrimental to children and future generations, and that the dismissal of the case “reflects fundamental misunderstandings of the economics of discounting.” The Plaintiffs’ amended complaint challenged the EPA’s policy of positive social discounting, which privileges current adults while giving less weight to today’s children that will be affected by the harms of today’s environmental policies in the future. The brief concludes that the EPA’s current analyses do not give full weight to the long-term benefits of pollution reduction policies enacted now and advises the Court to reverse the District Court’s dismissal.

Signatories to the amicus curiae brief: Dr. Elizabeth A. Stanton, Dr. Eban Goodstein, Dr. Robin Hahnel, Dr. James K. Boyce, Dr. Gerald Epstein, Dr. Michael Ash, Dr. Bryndís Woods, Dr. Jordan Burt, and Dr. Tanya Stasio.

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News: Economists, physicians and legal scholars back kids climate lawsuit

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Alabama Power’s Plant Miller: An Economic Assessment of Alternative Portfolios

Client: Southern Environmental Law Center (SELC)

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

July 2025

On behalf of the Southern Environmental Law Center, Senior Researcher Joshua R. Castigliego, Researcher Jordan Burt, PhD, and Principal Economist Tyler Comings prepared a report that evaluates four alternative portfolios to demonstrate that the continued business-as-usual (BAU) operation of Alabama Power’s James H. Miller Jr. Electric Generating Plant (also known as “Plant Miller”) is uneconomic and not in the best interest of customers.

One method of comparing alternative resource portfolios is to examine customer costs on a “levelized” basis—which normalizes total costs by total generation (in megawatt-hours or “MWh”) over an assumed time period. The levelized cost of energy (LCOE, in $ per MWh) provides insight into how each of the alternative portfolios compare to one another regardless of the total energy provided by each portfolio. Among its four modeled alternatives, AEC finds that replacing Plant Miller with clean energy and storage resources is cheaper on a levelized cost basis than keeping the plant operational into the 2040s.

Alabama Power should also continually evaluate the costs and risks of keeping the plant on-line by looking at viable alternatives. Although the alternative portfolios presented in this report are meant to be illustrative, the results of the analysis have demonstrated that the continued operation of Plant Miller (with or without carbon sequestration retrofits) is uneconomic, and Alabama Power would be able to provide customers with cost savings by investing further in clean energy resources. In order to determine the most cost-effective replacement of Plant Miller, Alabama Power should periodically conduct capacity expansion modeling that considers the retirement of Plant Miller in the context of the Company’s entire system.

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Testimony on LG&E-KU’s Certificates of Public Convenience and Necessity and Site Compatibility Certificates

Client: Kentuckians for the Commonwealth, Kentucky Solar Energy Society, Metropolitan Housing Coalition, and Mountain Association

Authors: Liz Stanton, PhD

June 2025

Principal Economist Elizabeth A. Stanton, PhD, submitted direct testimony before the Kentucky Public Service Commission to assess the load forecasting assumptions utilized in the 2025 request for approval for Certificates of Public Convenience and Necessity (CPCN) filed by Louisville Gas and Electric Company and Kentucky Utilities Company (LG&E-KU) in Kentucky PSC Case No. 2025-00045. In her testimony, Dr. Stanton reviews the Companies’ 2025 CPCN Load Forecast and assesses the methodology, assumptions, and findings of their economic development growth forecast, particularly as they related to projected growth in data centers.

Dr. Stanton recommends that the Companies employ a short-term forecast of new data center and other large customer load based on concrete evidence that there is a high likelihood that such load will actually come online, while discounting or excluding possible large customer load that is merely speculative or has a low likelihood of materializing, and presents an alternative framework for using probability weighting to forecast future load growth from data centers.

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Basin Electric's Coal Fleet: Risks to Continued Operation and Opportunities for Replacement

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

Client: Western Organization of Resource Councils

June 2025

On behalf of the Western Organization of Resource Councils, this AEC report evaluates the risks associated with continued operation of Basin Electric’s coal-fired plants and outlines opportunities for replacement with lower-cost clean energy resources. The continued operation of Basin Electric’s coal plants entails important risks to Basin Electric, its members and members’ ratepayers, including risks presented by:

Federal oversight: In 2019, Basin Electric became subject to Federal Energy Regulatory Commission (FERC) oversight, which means Basin Electric is facing greater scrutiny of whether continued operation of its coal plants is most prudent for its members and their ratepayers.
Competition in Southwest Power Pool (SPP): Basin Electric’s forthcoming full membership in the Southwest Power Pool (SPP) risks that Basin Electric’s coal plants will operate less often because more of its coal generation will compete in every hour of the day with every other resource in SPP’s marketplace.
Environmental regulations: There are cost risks for Basin Electric’s coal-fired power plants related to new emission and pollution control technologies to comply with federal environmental regulations including: the Regional Haze Rule, the coal ash waste rules, and carbon pollution standards.

AEC finds that Basin Electric can hedge against risks to its coal-fired resources by taking advantage of cost-saving opportunities to replace coal resources with cheaper wind and solar resources—resources which become even more cost-effective when coupled with federal incentives, funding, and financing streams targeted specifically at electric cooperatives to pursue them.

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Assessing U.S. Electric Grid Operators' Governance: Transparency, Accessibility, Accountability

Authors: Bryndis Woods, PhD, Deja Garraway, Alicia Zhang, PhD, Sagal Alisalad, Sumera Patel

Client: Slingshot

May 2025

On behalf of Slingshot (and their participation in the broader, grassroots Fix the Grid campaign in New England), this AEC report card utilized approximately 250 sources—including grid operator documents, research reports, and expert testimony—to develop and assign points across 34 metrics among three categories: 1) transparency is making information and materials publicly available; 2) accessibility is facilitating public awareness and involvement in grid operator processes; and 3) accountability is structuring governance and decision-making processes to incorporate viewpoints reflective of the diversity of the communities in each grid operator's territory.

The primary finding of the report card is that none of the seven U.S. grid operators perform particularly well in any assessment category and there is considerable room for improvement across grid operators in terms of transparency, accessibility, and accountability. The highest overall grade was a C+ earned by CAISO due to its strong performance in the accountability category. The lowest overall grade was an F earned by ISO-NE due to its receiving a failing grade in the accessibility and accountability categories. The five remaining grid operators (PJM, MISO, SPP, ERCOT and NYISO) each received an overall grade ranging from C- to D-.

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News: Consumer Liaison Group Discusses ISO-NE’s Failing Accessibility Grade

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Clean Energy Expansion: Recommendations for Georgia Power

Authors: Tanya Stasio, PhD, Jordan Burt, PhD, and Elisabeth Seliga

May 2025

Senior Researcher Tanya Stasio, PhD, Researcher Jordan Burt, PhD, and Assistant Researcher Elisabeth Seliga prepared a report that reviews the Georgia clean energy policy landscape, assesses Georgia Power’s existing fossil fuel-fired power plants and reviews Georgia Power clean energy program offerings. AEC identifies several sites of Georgia Power-owned retired and operating fossil-fuel energy infrastructure and recommends that Georgia Power consider replacing these sites with clean energy sources such as a solar plus storage facility. In addition, AEC recommends the Company re-assess retirement plans for fossil fuel plants with higher environmental costs that are expected to operate past 2025. Lastly, AEC provides recommendations to expand Georgia Power’s clean energy program offerings and increase customer participation in its existing programs.

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Identifying Priority Areas for Clean Energy Expansion and Emissions Reduction Opportunities

Authors: Tanya Stasio, PhD, Elisabeth Seliga, Elizabeth A. Stanton, PhD

April 2025

Senior Researcher Tanya Stasio, PhD, Assistant Researcher Elisabeth Seliga, and Principal Economist Elizabeth A. Stanton, PhD, prepared a white paper that provides energy, economic, environmental, and equity criteria that can be used by states, regional organizations, or other entities to identify priority areas for clean energy expansion and emissions reduction efforts within a particular jurisdiction. In addition to providing a pathway for identifying efficient and equitable locations for clean energy expansion efforts, these criteria may be helpful for prioritizing efforts to secure funding to support clean energy projects.

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LG&E-KU’s 2024 Integrated Resource Plan: An Assessment

Client: Mountain Association (MA), Kentuckians for the Commonwealth (KFTC), Kentucky Solar Energy Society (KYSES), and Metropolitan Housing Coalition (MHC)

Authors: Joshua R. Castigliego, Elizabeth A. Stanton, PhD

March 2025

On behalf of the Mountain Association (MA), Kentuckians for the Commonwealth (KFTC), Kentucky Solar Energy Society (KYSES), and Metropolitan Housing Coalition (MHC) (collectively, the “Joint Intervenors”), Senior Researcher Joshua R. Castigliego and Principal Economist Elizabeth A. Stanton, PhD prepared a white paper that sets out best practices for IRP modeling and reporting, and assesses the Louisville Gas and Electric Company (LG&E) and Kentucky Utilities Company (KU) (collectively, LG&E-KU) 2024 IRP filed on October 18, 2024 in Case No. 2024-00326 based on those criteria.

AEC’s best practices are organized into five categories: (A) Demand-Side Analysis; (B) Supply-Side Analysis; (C) Modeling Structure; (D) Selection of Recommended Plan; and (E) Stakeholder Input. Through its best-practices assessment, AEC finds that LG&E-KU’s 2024 IRP is missing critical components and includes errors in forecasting key assumptions, resulting in an overall flawed least-cost resource plan selection. LG&E-KU’s failure to follow IRP best practices results in resource decisions that are not properly informed (or justified) by comprehensive IRP modeling, leading to possible adverse effects on ratepayers. In particular, the flawed IRP findings may result in support for uneconomic resource additions in near-term CPCN applications.

Link to White Paper

Link to Joint Intervenors’ Comments

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Testimony on East Kentucky Power Cooperative Certificates of Public Convenience and Need

Client: Appalachian Citizens’ Law Center, Kentuckians for the Commonwealth, and Mountain Association

Authors: Liz Stanton, PhD

February 2025

Principal Economist Elizabeth A. Stanton, PhD, submitted direct testimony before the Kentucky Public Service Commission (“the Commission”) in response to the 2024 request for approval of Certificates of Public Convenience and Need (“CPCN”) filed by East Kentucky Power Cooperative, Inc. (“EKPC”). In her testimony, Dr. Stanton assesses EKPC’s: annual and peak customer demand forecasts, with a focus on its Winter Peak; alternative supply resource options; modeling and resource selection methods; and rate impacts. Dr. Stanton’s review finds that EKPC has not adequately supported its winter peak demand forecast, failed to provide the modeling and analytical support needed to justify the CCGT, and failed to demonstrate that the CCGT is superior to other available alternatives such as battery storage, demand response, or peaking resources.

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A Community Assessment of Health Impacts from the Pittsfield Generating Facility on Local Communities

Client: Massachusetts Clean Peak Coalition

Authors: Jordan Burt, Elisabeth Seliga, Tanya Stasio, PhD, Lila McNamee, and Liz Stanton, PhD

February 2025

On behalf of the Massachusetts Clean Peak Coalition Researcher Jordan Burt, Assistant Researcher Elisabeth Seliga, Researcher Tanya Stasio, PhD, Research Assistant Lila McNamee, and Principal Economist Liz Stanton, PhD, prepared a report that summarizes the negative health impacts of fossil fuel-fired emissions on communities living near the Pittsfield Generating Facility. The report identifies three key takeaways:

As long as the Pittsfield Generating Facility is in operation, it has the potential to produce much higher greenhouse gas emissions and co-pollutants in any given year.
EJ and other vulnerable communities live in close proximity to the Pittsfield Generating Facility, increasing vulnerability to adverse health outcomes.
Replacing the fossil fuel-fired plant with clean energy resources can reduce emissions in the area.

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Duke KY IRP Comments

Client: Sierra Club

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

January 2025

Principal Economist Tyler Comings, Senior Researcher Joshua Castigliego, and Researcher Jordan Burt co-wrote comments on the Duke Energy Kentucky 2024 Integrated Resource Plan (IRP). The comments focused on the utility's decision to co-fire a coal unit (East Bend Unit 2) with natural gas. We found that full conversion of the unit to gas was more cost-effective and reduced regulatory risk.

Link to Comments

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Testimony on Alabama Power Company Petition for Certificate of Convenience and Necessity

Client: Energy Alabama and GASP

Authors: Elizabeth A. Stanton, PhD

January 2025

Principal Economist Elizabeth A. Stanton, PhD, submitted direct testimony before the Alabama Public Service Commission (“Commission”) in response to Alabama Power Company’s proposed Lindsay Hill Generating Station (“Lindsay Hill”) purchase. In her testimony, Dr. Stanton addresses Alabama Power’s failure to satisfactorily consider alternative resources to its proposed purchase and determines that without consideration of alternative resources, it is not possible to conclude that the Lindsay Hill purchase is the lowest cost option. Dr. Stanton’s review of Alabama Power’s Lindsay Hill Certificate of Convenience and Necessity (“CCN”) Petition finds that the proposed purchase would decrease the Company’s resource diversity and increase its reliability risks. To address these concerns, Dr. Stanton recommends the Commission require Alabama Power to:

Include portfolio diversity risks in IRP and CCN cost modeling
Issue a new Capacity request for proposals (“RFP”) that does not exclude bids by alternative resources including battery storage and solar plus storage resources
Require that cost modeling be conducted for more than one resource (or more than two versions of the same resource) to be considered for CCN approval
Reissue RFPs when there are insufficient bids submitted to obtain proposals for a minimum of four resources and three resource types.

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Rooftop Coverage Alternatives: Assessing Benefits for Grove Hall

Client: Greater Grove Hall Main Streets (GGHMS)

Authors: Elisabeth Seliga, Sumera Patel, Joshua R. Castigliego

January 2025

On behalf of Greater Grove Hall Main Streets (GGHMS), Assistant Researcher Elisabeth Seliga, Assistant Researcher Sumera Patel, and Senior Researcher Joshua R. Castigliego prepared an issue brief examining a set of rooftop coverage alternatives (i.e., solar photovoltaic (PV), green, white, blue, and brown roofs) aimed at addressing the unique energy and environmental challenges faced by Boston’s Grove Hall community, highlighting the potential for a systems approach encompassing each rooftop coverage alternative to enhance energy efficiency and alleviate energy burden in a region characterized by urban heat island effects and a high share of environmental justice (EJ) populations. The issue brief provides actional recommendations for GGHMS to implement a combination of rooftop coverage alternatives to mitigate energy and environmental disparities, promote environmental resilience, and foster a healthier urban environment in Grove Hall.

Link to Issue Brief

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