The Public Utilities Regulatory Authority approved a rate hike for United Illuminating’s electric customers on Tuesday in its first major decision following the resignation of the authority’s former chair, Marissa Gillett.

The decision will allow the company to collect more than $450 million in revenues over the next year, an increase of about 17% — or $66 million over its currently-authorized revenues. Those revenues will be collected through new distribution rates, which will go into effect beginning Nov. 1.

While the additional $66 million is less than the original $105 million increase the company sought in this case, it’s also a sharp increase from the $28.6 million increase recommended by PURA before Gillett stepped down earlier this month amid a wave of scrutiny from utility officials and state lawmakers.

Officials for the Orange-based utility had publicly threatened to sue PURA over the earlier proposal, which they argued would have weakened the company’s financial footing and forced dozens of layoffs. Prior to Tuesday’s ruling, UI had offered a resolution that would have increased the company’s revenues by $63.7 million — slightly less than the $66 million PURA approved Tuesday.

A spokesperson for UI declined to comment on the ruling.

According to estimates released by PURA on Tuesday, the decision will increase the average UI customer’s electric bill by about $10 a month.

The Office of Consumer Counsel, which represents the interests of utility customers before PURA, estimated a slightly higher bill impact, around $13 a month. In a statement on Tuesday, Consumer Counsel Claire Coleman expressed disappointment in the the decision — which she said comes at “particularly challenging” time for the authority.

“Given that the final decision gives UI more revenue than the company’s own stated bottom line for providing safe and adequate service, I hope that UI will accept the decision rendered by its regulator and cease its practice of filing a battery of appeals,” Coleman said in an emailed statement. “This should allow the Company to turn its focus toward improvements and efficiencies that can still be achieved in the delivery of electricity to customers.”

The decision allows UI to achieve a 9.25% return on its investments in Connecticut. PURA trimmed that amount by a fraction of a percentage point, citing several issues including the company’s failure to complete its remediation of the abandoned English Station power plant in New Haven.

That cleanup effort was required as part of UI’s 2015 merger with Spanish power company Iberdrola. To date, however, PURA said the company has spent only slightly more than half of the $30 million it originally promised as part of the effort.

“Time is thus of the essence in this endeavor, yet the remediation of English Station lingers nearly a decade after the Authority approved the Merger Decision with remediation as an express condition thereof,” the decision states.

Regulators did give UI credit — and reduced the company’s existing penalty related to the English Station cleanup — for improving security measures at the site and removing 1,120 tons of contaminated soil from underneath a boiler at the plant. New Haven is currently considering purchasing the property with the hope of transforming it into a waterfront park.

Regulators also docked UI’s potential profits for noncompliance with PURA’s orders regarding the rollout of so-called “smart meters” aimed at helping customers reduce their electricity usage.

John Erlingheuser, an advocacy director for AARP Connecticut, said in a statement Tuesday that the decision offered a “mixed outcome” for consumers.

“While PURA set the return on equity at 9.25%, a figure below the national average and significantly less than UI’s original request, the decision still results in an average increase of approximately $10 per month in distribution charges on customer bills,” Erlingheuser said. “This added cost comes at a time when many residents are already grappling with the pressures of inflation and rising living expenses.”

The final decision was approved Tuesday by PURA Vice Chair David Arconti and Commissioner Michael Caron.

The newly-appointed chair of the authority, Thomas Wiehl, recused himself from the vote as he had previously weighed in on UI’s application while serving as a staff attorney for OCC. Commissioner Janice Beecher also did not participate in the vote as her first day at PURA was Tuesday, and she said she did not have enough time to prepare.

Wiehl was appointed this month by Gov. Ned Lamont to replace Gillett, who stepped down following a long and bitter dispute with the utilities, who have filed lawsuits accusing her of bias and boxing out her fellow commissioners to issue decisions that harmed the company’s financial reputation. Those lawsuits remained pending as on Tuesday.

“After months of relentless legal attacks, United Illuminating succeeded in running off its chief regulator,” Attorney General William Tong said in a statement responding to PURA’s decision Tuesday.

“For those who spent these last months fixated on personalities and politics, this decision is a stark reminder of what this fight was always about. It was about millions upon millions of dollars that Connecticut families will now pay to increase United Illuminating’s bottom line. We cannot lose sight of that, and we must redouble our efforts to address the crisis of affordability in our state,” Tong said.

In a legal filing earlier this week, attorneys in Tong’s office conceded that some of Gillett’s actions while serving as chair violated state law.

Lamont’s office declined to comment on the decision.

Caron defended the outcome during Tuesday’s meeting, noting that he and Arconti had allowed time for the OCC and other interested parties to attempt to reach a settlement with UI following Gillett’s resignation.

Those negotiations, however, failed to produce an agreement. In the meantime, Caron said PURA staff were put to work revising the earlier draft in response to comments it received from stakeholders.

“This isn’t perfect by any means, but I fully believe it gets the rates right with the revenue that is sufficient, but no more than sufficient, to prudently manage the system,” Caron said.

Tom Swan, executive director of the Connecticut Citizens Action Group, called the decision “overly-friendly” to UI, and expressed concern that Arconti — who worked briefly as a lobbyist for the utility — was one of two votes to approve it.

Arconti did not address his prior work for UI in his remarks on Tuesday. He left the company in mid-2024, before the latest rate case was filed in November.

“The revenue requirement we are approving today will support continued reliability of essential services and help with addressing aging infrastructure while striking a balance between affordability and the need for ongoing system improvements,” Arconti said.

UI serves about 341,000 customers in south-central Connecticut. Its last rate case was decided by PURA in 2023.

This year’s rate case was the first of three major decisions expected by PURA in the aftermath of Gillett’s departure.

The authority is scheduled to rule on the pending rate case for the Yankee Gas Company on Nov. 5, followed by the proposed sale of Eversource’s Aquarion Water Company to the South Central Regional Water Authority on Nov. 19.