Indiana backslides on commitments to clean energy, Sierra Club report says

Indiana’s five major utilities are “backsliding” on their clean energy transitions, according to the Sierra Club’s 2025 Dirty Truth Report.

None of the utilities in question — AES Indiana, CenterPoint Energy, Duke Indiana, Indiana Michigan Power (I&M)and The Northern Indiana Public Service Company (NIPSCO) — found themselves with a better score in the report’s most recent iteration than in years past.

Scores were awarded on a scale of 1 to 100, largely based on whether utilities are retiring coal plants by 2030, not building new gas plants through 2035, and how the utility’s plan transitioned toward clean energy, also by 2035.

Indiana’s utilities largely did not fare well against these standards.

A spokesperson from Duke Indiana said the utility’s “utmost obligation” is to provide reliable and low-cost energy to customers, which can get tricky when renewable sources, like wind and solar, are weather dependent.

Still, Megan Anderson, a senior organizer with the Sierra Club’s Beyond Coal campaign said she’s worried that utilities are keeping aging coal plants online and building new natural gas plants in response to an upcoming data center boom. If the boom doesn’t happen on the predicted scale or if the centers quickly become more data efficient, she worries that ratepayers will be stuck with the burden of maintenance and repairs for coal plants long past their prime.

Pollution from coal plants remains a major concern for the Sierra Club. Even when utilities meet environmental regulations, which continue to be rolled back, people can still suffer, according to Nicole Chandler, who also works on the Beyond Coal campaign. In her opinion, meeting these regulations should just be the beginning.

“That’s the minimum,” she said. “People are still being harmed by what’s happening in these fenceline communities from the pollution.”

When air pollution in the form of health of sulfur dioxide, nitrous oxide, particulate matter and mercury spew from fossil fuel burning power plants, the health of communities living nearby are at risk, according to the Environmental Protection Agency.

The Sierra Club’s report demonstrates that state and federal desires to keep the coal industry afloat is reflected in local utility decision making. But despite President Donald Trump administration’s tirade against renewable energy, Indiana utilities are pursuing an “all of the above” approach to solve the precarious future of Indiana’s energy needs. Coal is staying online, natural gas is being built and renewables are here to stay.

Here’s how each utility stacked up in the Sierra Club’s report.

AES Indiana

AES tied for Indiana’s highest utility score, with a 57%. The Sierra Club cited AES’s interest in building two new gas burning power plants to serve big customers, like data centers, in their explanation for the score. 

Mallory Duncan, a spokesperson for AES, wrote in a statement that the utility has not filed any plans for such plants, adding that future development would comply with state and federal regulations.

She added the utility will also likely be the state’s first investor-owned utility to go coal-free, and it has invested widely in renewable energy like wind and solar. AES is also paving the way forward in Indiana with construction of battery storage systems, which can store energy from wind and solar to be discharged after the sun sets or wind calms.

CenterPoint Energy

CenterPoint Energy’s score took a hit this year, earning a 33%.

The utility is in the middle of writing its next Integrated Resource Plan (IRP), which is a long-term guide map for energy generation, and the drafts show the utility heading in a new direction.

CenterPoint’s last report planned to retire all coal generation by 2023. The Sierra Club noted that now, drafts of the updated IRP show the utility retaining coal past 2030.

Noah Stubbs, a spokesperson for CenterPoint Energy, wrote in an email to IndyStar that the Sierra Club’s report “does not fully reflect the broad set of considerations utilities must weigh today, including rising resource costs, shifting federal incentives and evolving environmental regulations.”

He added that 70% of the company’s coal fleet has been retired or exited since the Integrated Resource Plan. CenterPoint also has plans for 1.1 GW of new generation by 2026, over half of which Stubbs said will be sourced from renewable energy projects.

Duke Indiana

The Sierra Club awarded Duke a 0% this year, which is the same score it received in the organization’s last report. 

Duke was initially planning to close its Gibson County coal plant in 2035, but the utility extended its life by three years, much to the ire of clean energy advocates, according to reporting from WFYI. Duke also proposed new natural gas plants, like in Vermillion County, Indiana, and the Sierra Club noted the utility has ditched plans to build out renewable energy. Almost 3,798 megawatts of renewable energy investments that were cut dropped from its long-term energy plan, according to the report.

Angeline Protogere, a spokesperson for Duke, wrote in an email to IndyStar that MISO, the agency running the energy market across most of Indiana, lowered the values assigned to renewable generation, which was an “important driver” in how they planned energy generation.

“We have to demonstrate that we have enough generation to serve our customers’ needs in every season,” said Protogere.

I&M

I&Mslid from a 66% last year to a 48% in 2025. The Sierra Club cited costs from coal plants being shifted solely onto Indiana customers.

Stephanie Smith, a spokesperson from I&M, stressed that the utility’s energy mix is designed to provide safe, reliable and clean power customers can count on around the clock in a statement. This mix includes fossil fuels like coal, natural gas, but also emission-free energy generation from nuclear, wind, solar and battery storage.

NIPSCO

After receiving an 80% last year, NIPSCO earned a 57% in 2025, tying with AES for top marks. 

As for the drop, the Sierra Club cited NIPSCO’s plans for new gas plant. Jessica Cantarelli, a spokesperson for NIPSCO, explained that while the utility committed to protecting human health and the environment, NIPSCO has to ensure reliability — a common theme across the Indiana utilities struggling to balance clean energy and dependability.

IndyStar’s environmental reporting is made possible through the generous support of the nonprofit Nina Mason Pulliam Charitable Trust.

Sophie Hartley is an IndyStar environment reporter. You can reach her at sophie.hartley@indystar.com or on X at @sophienhartley.