Extreme Summer Heat Put Maine's Grid to the Test, Highlighting Need for Infrastructure Upgrades
Crews safely and quickly responded as extreme heat put strain on aging grid infrastructure.
Augusta, ME – September 21, 2026 – Central Maine Power (CMP), a subsidiary of Avangrid Inc., today reported a record number of heat-related grid events across its 11,000-square-mile service territory as Maine experienced its second-hottest meteorological summer on record.
CMP has proposed upgrades to electrical infrastructure to address capacity and extreme weather challenges. The company has publicly highlighted the need for these upgrades as part of ongoing efforts to strengthen reliability and support growing energy needs. CMP is advancing these solutions to improve reliability, increase system capacity and ensure crews can continue providing safe, reliable service to customers.
“We cannot ignore the reality and challenge in front of us when it comes to the strain that extreme heat is placing on aging components of Maine’s electric grid,” said Linda Ball, President and CEO of Central Maine Power. “We must implement solutions like upgraded substation transformers that are ready to handle the energy demand that comes with extreme heat. We’ve also seen the value of having mobile substations ready to deploy as our crews used these to alleviate equipment that either failed or could have failed on these hottest days.”
High temperatures can increase demand for electricity and place strain on electrical equipment like lines and transformers. CMP grid equipment is designed to operate safely for a limited time above a defined strain threshold. This year, on July 3, prolonged extreme heat on a holiday weekend pushed some of that equipment, like substation transformers in Auburn and in tourism destination Ogunquit, beyond that limit. In several communities, CMP conducted temporary protective outages to prevent damage to critical equipment, an unprecedented measure during periods of extreme heat. Virtually all temporary measures to alleviate demand on these areas of the electric grid were deployed by crews, including the installation of a mobile substation brought to Ogunquit from Augusta with the help of a Maine State Police escort.
CMP's grid strengthening plans, currently under review by the Maine Public Utilities Commission (MPUC), include replacing two existing transformers at a York County substation with larger units to increase system capacity and backup capability, while upgrading communications technology to support the area's growing energy needs. CMP’s proposals also include replacing more substation transformers in Cumberland, Franklin, Kennebec, Lincoln, and Penobscot counties. Additional grid-hardening investments include installing thousands of stronger distribution poles, deploying hundreds of smart devices that enable faster remote restoration, and expanding vegetation management to reduce tree-related outages.
Work to restore power or prevent outages was not limited to teams in the field. CMP Energy Control Center operators and support staff worked around the clock for multiple days, coordinating real-time communications with field personnel and executing critical switching operations to safely manage infrastructure. Previous investments in smart grid technology were instrumental in maintaining service for thousands of customers during periods of extreme demand. This equipment enabled control center operators to find solutions remotely such as shifting how power was flowing on individual lines to alleviate equipment under strain.
CMP's plans for continued upgrades come as the company reports that approximately 15,000 customers experienced heat-related power interruptions during the summer of 2026. The company anticipates a final decision from the Maine PUC on its proposals subject to the commission's review and approval.