A little short: CMLP billing error will cost customers

A five-year-old calculation error is hitting Concordians’ electricity bills.

It will cost the average residential customer an extra $6.74 per month on top of their regular bill for the next five years as the Acton Municipal Light Plant moves to recoup $6.6 million in lost revenue.

A new set of accountants reviewing CMLP’s 2025 financials found the problem during their recent audit, Director Jason Bulger wrote in a memo to the Light Board. The board approved what’s effectively a surcharge for ratepayers at a September 23 meeting.

“I’m concerned that we and the former auditors look like dummies for not knowing about this,” Light Board member Warren Leon said during the session. 

Presented with the choice to recover revenue over three, four, or five years, he pushed for the longest horizon to minimize the monthly charge. 

Customers will pay an extra $0.00728 per kilowatt hour. This will add up to about $400 more over five years for a household with average electricity use.

The light plant buys power to distribute to its customers. At issue is a formula that CMLP uses to account for fluctuating wholesale costs.

Budget writers can only estimate how much they’ll need to spend. The light plant’s power cost adjustment lets officials issue a refund or collect extra cash as prices rise and fall. 

Based on the formula the light plant had used since 2021, CMLP officials thought they owed customers $4.8 million back in overcharges. 

The calculation wasn’t factoring in electricity that escapes as it runs through transformers and lines. Counting “line loss,” officials found they’d underbilled. 

A double hit

Residents had been getting a monthly credit worth $3.70 for the average household. That’s gone, and Concordians will see the extra charge on their October bills, Bulger told The Acton Bridge. 

Leon said that “the fact that nobody noticed this problem” sooner suggests that while it’s worth fixing, it’s not urgent. 

Member Nicole Grosner asked whether CMLP could correct its formula but not charge customers for the last five years of underbilling. 

Bulger said he doesn’t think CMLP’s auditors would let them write off the loss. 

Light plant leaders say they switched from their old auditor, CBIZ CPAs, to Goulet, Salvidio & Associates partially because Goulet specializes in working with municipal light plants. 

“They understand that they need to think about [electricity transmission] losses,” CMLP Assistant Director of Power Supply and Energy Management Laura Scott said. “A regular accountant isn’t going to know that.”

CMLP has undergone turnover since 2021. Bulger defended the team that developed the flawed arithmetic. 

This wasn’t “an oopsie that nobody saw before,” he told the Light Board. “People with the best of intentions went down a path” before others realized “that’s probably not [an] advisable way to do that thing.” 

Select Board reactions

Auditors presented their larger review to the town’s Financial Audit Advisory Committee. 

Experts found what audit committee Chair and Select Board Clerk Cameron McKennitt described as a “laundry list” of other accounting practices to clean up. But they didn’t issue the kind of “material weakness” findings that sparked concern after they appeared in a round of delayed 2024 audits.

Auditors signed off on the light plant’s financials despite the issues they uncovered. 

Goulet’s Heather Isaacs said officials were making changes and she expects the 2026 audit will be “much cleaner.” 

Select Board members reacted with surprise when McKennitt relayed the formula problem. Board Chair Wendy Rovelli called it “unfortunate” and told The Bridge she wanted more information. 

“It’s nice to have fresh eyes,” she said of the new auditors who caught the error.