PORTLAND, Maine (AP)   Documents show 97,000 Maine power customers saw their bills increase by at least 50 percent between December 2017 and February 2018.

WMTW-TV reports Central Maine Power filed documents with the state Public Utilities Commission Tuesday determined 140,000 bills–and 97,000 customers –fit the criteria of “a year-to-year monthly or average daily use increase of 50 percent or more.”

The state launched an audit of CMP after about 1,500 customers complained about high winter power bills.

The utility previously said an October windstorm and cold winter temperatures both led to the usage increases. CMP says it expects the audit will determine if it provides “accurate measurements of customer usage.”

The commission ruled April 4 power customers disputing their bills have to pay at least a portion of the cost.