Central Maine Power is pushing an industrial high-voltage line through Cumberland, Falmouth, Portland, Westbrook, and Yarmouth. CMP's own filings put the price tag at $546.97 million — and unless intervenors succeed in changing the record, that cost lands on Maine ratepayers through delivery rates, not on the region as a whole.
CMP has applied to the Maine Public Utilities Commission for a Certificate of Public Convenience and Necessity to build Phase 1 of the "Greater Portland Transmission Upgrades" — new and rebuilt high-voltage lines and two new or expanded substations running through Cumberland, Falmouth, Portland, Westbrook, and Yarmouth. In several of these neighborhoods, this would be the first time high-voltage transmission infrastructure has been sited there at all, rather than an upgrade of an existing corridor residents already live alongside.
Landowner intervenors in the case — represented informally as the Falmouth Corridor Intervenors — have formally challenged whether the project is even needed at the scale CMP proposes. Their motion argues the load forecast behind the project relies on the same 2024 ISO New England forecasting methodology that Maine's own Office of the Public Advocate has already flagged for overestimating electric-vehicle and heat-pump adoption. The Commission's July 15, 2026 order expressly left that question open for this case.
Intervenors have also filed formal data requests asking CMP to state, in plain language, exactly how close energized 115kV wires will come to homes — including any home located near or under the line — and whether CMP has assessed places where the standard clearance can't be met, including near school bus stops where children wait outdoors.
Need and cost are the heart of our challenge — but they're not the whole case. Here's the rest of it, briefly.
CMP's design calls for roughly 90–120-foot steel structures and 100–150 feet of total cleared corridor — in several neighborhoods, the first high-voltage infrastructure ever sited there. Published research on transmission lines and nearby home values reports meaningful price effects for close-by properties.
ISO New England determined Phase 1 addresses localized needs, not regional grid reliability — so none of the $546.97M qualifies for regional cost-sharing. The full amount is instead recovered through Maine customers' delivery rates, and intervenors are asking the Commission to weigh whether that allocation and scale are justified.
Intervenors have raised concerns about how well affected property owners across all five towns were notified before CMP filed, and about a hearing schedule that leaves little time for residents to review technical filings. Maine law (35-A M.R.S. § 3132(2)) lets the Commission grant schedule extensions for exactly this kind of disadvantage.
Showing up — in person or on the live stream — puts community opposition directly in front of the Commissioners and the Hearing Examiner. Every date below is filed under Docket No. 2025-00276.
Dates and venue per Docket 2025-00276 filings as of Sept 2026 — the Commission can amend its schedule, so confirm on the CMS portal before you travel. Clerk's office: (207) 287-3831.
Submit a formal petition to intervene before the Commission to gain direct legal standing, request data, and join joint filings alongside other affected landowners.
Ask your Town Manager and Councilors to formally petition the MPUC for a procedural pace that gives residents time to review CMP's technical filings, and to weigh in on routing and setback concerns before final design is locked in.
Your state senator and representative can press the Commission directly and have more day-to-day leverage over MPUC proceedings than a town council does. Find and reach out to yours — a short call or email asking them to look into Docket 2025-00276 goes a long way.
If your property is along the route, photos looking toward the corridor help our technical consultant and legal team document real visual and access impacts for the case record.
Submissions are reviewed by our team before any public use — nothing is posted automatically.
We've engaged independent energy consultant Kay Aikin on a preliminary, no-cost basis, and filed for state intervenor funding under 35-A M.R.S. § 1310-A. Community contributions close the gap while that funding is pending — every dollar goes toward independent technical review and legal counsel for the case.
Scan the code or use the link above. Contributions to the fund are not tax-deductible.
We can't tell you exactly what CMP's proposed route will do to your specific home, and we aren't claiming CMP has caused any particular loss. What we can share is what published, independent research generally finds about homes near high-voltage transmission corridors — so you can weigh it for yourself.
CMP's own filings include maps of the proposed corridor through Cumberland, Falmouth, Portland, Westbrook, and Yarmouth — worth a look before using the estimator below.
What this is — and isn't. These ranges come from published, independent research on transmission lines and residential property values in general. They are not a property-specific appraisal, and they are not a claim that CMP's project has caused, or will cause, any particular loss to any particular home. We're sharing this because it's publicly available information directly relevant to residents deciding how to respond to this case — not as an accusation against CMP.
Not sure which zone your property falls in? Submit a photo from your property and our team can help you get oriented relative to the proposed route.
Everything below is drawn directly from filings under Docket No. 2025-00276. Formal PDFs are being finalized for handouts and door-knocking — read the summaries now, or download a plain-text copy.
A one-page summary of the project, its cost, the towns affected, and the open questions in the case — built for sharing at your door or at a town meeting.
What CMP has been formally asked to answer, and why intervenors dispute the underlying need — sourced from the joint data requests and the motion on need.
Step-by-step instructions for photographing and logging how the proposed line would affect your property's view, access, and use — useful whether or not you end up filing testimony.