A Central Maine Power technician installs one of the first “smart” meters at an apartment building in Portland in 2010. Credit: Joel Page | AP

With customers continuing to report what they consider to be excessively high electric bills, the Office of the Public Advocate on Monday asked Maine regulators to conduct further tests of problematic Central Maine Power accounts.

Thousands of Maine customers have received bills that are 50 percent or more higher than usual since CMP began using a new customer billing system in October 2017, the same time a major windstorm knocked out power to customers for up to a week.

The move comes two weeks before the Maine Public Utilities Commission’s scheduled hearings about ongoing complaints on July 16 in Portland, July 18 in Farmington and July 22 at the PUC’s office in Hallowell.

Even though an audit last December by Liberty Consulting Group of Pennsylvania blamed the high bills on weather and not CMP’s billing system, the high bills persisted, with customers continuing to complain to the utility and to the PUC.

CMP spokeswoman Catharine Hartnett said the utility welcomes the additional look at the system in hopes that consistent answers will help the public regain trust in the company and its system.

“CMP has committed to providing the specific customer information sought by the [Office of the Public Advocate] as part of the ongoing investigation into the metering and billing system,” she wrote in an email. “We trust it will confirm the findings of the Liberty Group’s thorough and lengthy review, which concluded last December, that CMP’s metering and billing system is working as intended, and customer bills are accurate.”

The public advocate wants to take a broader look than Liberty did, including delving into information stored on meters and how it compares to bills. The new study would examine billing that occurred after Liberty concluded its audit in April 2018 and run until the present.

In its filing with the PUC on Monday, the office proposed focusing on specific accounts that are problematic.

The PUC’s Consumer Assistance and Safety Division referred 1,369 accounts involving customers who complained about high usage on their bills since May 2018 to be examined further.

The public advocate wants to see copies of customer bills for the two billing periods before the date of the high usage complaint, as well as the subsequent billing period. It also wants the account number, meter number and daily register reads.

By analyzing the data, the public advocate’s office aims to determine the number of accounts with anomalies. It also wants to request more information from CMP, including asking the utility to test hourly interval data and other information that could shed light on the source of potential problems.

If no problem is found, the public advocate will consider next steps. The office estimated it would take eight weeks from the time it receives the data from CMP to conduct the testing and present its findings in testimony.