Company Behind Three Mile Island Restart Gets High Marks on Emissions

WASHINGTON — Constellation Energy, the company that’s reopening the Three Mile Island nuclear power plant in Pennsylvania to provide power to Microsoft, is once again tops among privately or investor-owned power producers when it comes to low carbon dioxide emissions.

According to the annual “Benchmarking Air Emissions of the 100 Largest Electric Power Producers in the United States” report, the Baltimore, Maryland-based firm boasts the lowest rate of carbon dioxide emissions among the 20 largest non-public power producers in the U.S.

The report, from the independent, London-based consultancy ERM, not only shows Constellation has achieved this distinction — and actually has done so for 11 years running — but that the company is significantly outpacing its competitors when it comes to emission reduction.

Its authors suggest the next cleanest generator among the list’s top 20 nonpublic companies had nearly 4.5 times the carbon dioxide emissions rate as Constellation. 

The emissions report is based on publicly reported generation and emissions data from the Energy Information Administration and the Environmental Protection Agency

It benchmarks key air pollutant emissions — including nitrogen oxide, sulfur dioxide, carbon dioxide and mercury — from the 100 largest U.S. power producers from the year 2022. 

Constellation, which bills itself as America’s largest producer of “clean, carbon-free energy,” produces about 10% of the nation’s emissions-free energy through a fleet of nuclear, solar, wind and hydroelectric plants.

At present, about 90% of its annual energy output comes from these sources, and according to its website, Constellation hopes to produce 95% carbon-free electricity by 2030 and 100% by 2040.

The restarting of Three Mile Island Unit 1, announced in September, is part of that strategy.

Most people, of course, remember the power plant located near Middletown, Pennsylvania, as the site of the worst commercial nuclear accident in U.S. history.

It was in the early morning hours of March 28, 1979, that a cooling malfunction caused part of the core to melt in the Unit 2 reactor of what was then called the Three Mile Island Nuclear Generating Station.

The partial meltdown released radioactive gases and radioactive iodine into the environment, and what’s widely seen now as governmental ineptness led to a delayed evacuation of the area.

The so-called “accident with wide consequences” inspired the anti nuke movement.

Largely ignored — or at least widely forgotten by the general public — was that the Three Mile Island Unit 1 reactor continued to produce power for decades.

Though located adjacent to the site of the meltdown, Unit 1 was a completely independent facility that generated enough electricity annually to power more than 800,000 homes.

Purchased by Constellation in 1999, Unit 1 was retired for “economic reasons” in 2019.

In its last year of operation, the plant was producing electricity at maximum capacity 96.3% of the time and employed more than 600 full-time workers with an annual payroll of about $60 million.

An additional 1,000 “highly skilled, mostly union craftspeople” supported the plant’s biennial refueling outages, Constellation said.

Constellation Energy hopes to have Unit 1, rebranded as the “Crane Clean Energy Center,” up and running and online in 2028.

To prepare for the restart, the company will make significant investments in restoring the plant, including revamping the turbine, generator, main power transformer and cooling and control systems. 

The company will also need approval from the Nuclear Regulatory Commission to restart the reactor, following a comprehensive safety and environmental review, as well as permits from relevant state and local agencies. 

In addition, Constellation Energy has said it will pursue a license renewal that will extend plant operations to at least 2054.

“As the nation’s number one producer of emissions-free energy, we are committed to ensuring our customers and communities have access to clean, reliable energy where and when they need it,” said Katie Ott, vice president of Sustainability and Climate Strategy, Constellation, in a written statement. 

“The Constellation team is working to extend the lives and increase the output of our nuclear units and innovating new solutions like restarting the Crane Clean Energy Center to power the nation’s critical infrastructure, including data centers, with zero-emission nuclear energy,” she added.

The 20-year power purchase agreement with Microsoft will help ensure the tech giant has ample access to energy as it expands its cloud computing and artificial intelligence programs.

State and company officials estimate the deal will create approximately 3,400 jobs and bring in more than $3 billion in state and federal taxes.

In addition, Constellation officials have said the agreement will add as much as $16 billion to Pennsylvania’s Gross Domestic Product.

“This agreement is a major milestone in Microsoft’s efforts to help decarbonize the grid in support of our commitment to become carbon negative,” said Bobby Hollis, vice president of Energy, Microsoft, in a written statement. 

“Microsoft continues to collaborate with energy providers to develop carbon-free energy sources to help meet the grids’ capacity and reliability needs,” he said.

The plant is being renamed in honor of Chris Crane, who was CEO of Constellation’s former parent company and who died in April 2024.

Throughout his career, Crane was an ardent advocate for the commercial nuclear power industry and its potential to power the nation.

According to the ERM’s “Benchmarking Air Emissions” report, zero-carbon resources generated approximately 41% of U.S. electricity in 2023. 

Nuclear energy led the way, the report said, comprising 44% of that total and 18% of all U.S. generation.

If Constellation Energy meets its goal of reopening the Crane facility in 2028, it will be coming online three years after the Palisades Nuclear Plant in Michigan will have become the first closed reactor in the U.S. to reopen.

Like Three Mile Island’s Unit 1, the Palisades nuclear plant was retired after falling on economic hard times. 

The plant closed in May 2022, and Holtec International purchased the plant from Entergy in June 2022 intending to decommission it. 

All that changed in late 2022 and early 2023 with the passage of the federal Inflation Reduction Act, and a package of state bills signed by Gov. Gretchen Whitmer in November 2023 that established a goal for Michigan to reach 100% carbon neutrality standards by 2040.

Acting through the Department of Energy, the Biden administration committed to conditionally offering Holtec International a $1.5 billion loan to reopen the facility.

If all goes to plan, that will happen in October 2025.

Dan can be reached at [email protected] and at https://twitter.com/DanMcCue