Maine Rooftop Solar Credits Expire After 12 Months: Check What Your Savings Estimate Counts

Your panels can be producing as expected while your savings fall short. For a Maine homeowner, one place to look is the credit bank on the utility bill. Credits that accumulate faster than your household uses them may eventually expire, even though the financing payment continues.

This article focuses on residential rooftop systems participating in Maine's net energy billing kilowatt-hour program. A community-solar subscription creates a separate payment relationship, discussed below. The commercial tariff-rate program should not be used to estimate residential rooftop savings.

The credit bank has a deadline

Under section 3(I) of Maine PUC Chapter 313, unused kilowatt-hour credits can offset usage within a rolling 12-month period. Once they expire, they cannot offset future usage, and the transmission and distribution utility does not compensate the customer for them. The rule also leaves non-usage charges payable. The current rule is listed as effective February 23, 2026.

A rolling deadline matters. Do not assume every credit survives until a single year-end cash-out. Ask the utility for the age of the credits in your account and the amount approaching expiration. An aggregate balance alone cannot answer either question.

For example, imagine a household whose credit bank keeps rising after its electricity use falls. The panels may have no performance problem. The financial problem may be that the proposal assumes the household will use electricity it no longer needs. A production chart and a credit-expiration record answer different questions.

Test the estimate against the home you actually live in

Set the original usage estimate beside the most recent complete year of bills. Did the proposal assume an electric vehicle, a heat pump or additional occupants? Did those changes happen? If a future purchase remains only a possibility, ask for a second savings scenario without it.

Next, separate three figures: electricity generated, credits actually used, and credits lost. Counting all production at a retail electricity price can conceal the effect of expiration. Ask the seller to identify where its calculation subtracts unused credits and retains charges the credits cannot offset.

Do not increase electricity consumption merely to avoid losing credits. Evaluate any proposed equipment purchase on its own cost and usefulness. An expiring balance is a reason to review the estimate, not an instruction to buy more equipment.

Read both bills if you subscribe to community solar

CMP explains that subscribers can receive a utility bill and a separate bill from their community-energy project. Its generation-details table includes allocated credits, banked generation and expired credits. Those entries are useful when reconciling what you paid for with what reduced your utility bill.

Do not assume utility credit expiration means a sponsor can retain every subscription payment. Current Chapter 313 section 4(L) requires a sponsor to credit the customer for the specified value of expired credits within 60 days and prohibits retaining the customer's payment for those credits. Keep the sponsor invoice, expiration entry and resulting adjustment together. That sponsor obligation is distinct from the utility's treatment of a rooftop owner's unused credits.

Build a useful review file

Gather the sales estimate, signed agreement, production history and bills showing the credit bank. Mark each mismatch as a question: Was usage overstated? Were expired credits omitted? Is a subscription adjustment missing? A dated question tied to a document is more useful than treating every disappointing bill as a panel failure.

Solar Exit's utility-billing review can help organize those issues. Bring the same records to a contract review if the promised savings and payment obligations do not line up. Credit expiration alone does not establish a right to cancel an agreement.

General consumer information, not legal, tax or electrical advice. Account treatment and contract options depend on the applicable documents and facts.