Washington's net metering cap, and the gauge that fills toward it

How the gauge fills

State law is simpler here than the acronyms suggest. It directs each investor-owned utility to keep net metering open to new customer-generators (the legal term for a customer who makes some of their own power) until the combined nameplate capacity of those systems reaches roughly four percent of the utility's peak demand measured back in 1996, per RCW 80.60. Nameplate capacity is just the maximum a system is rated to produce, the figure stamped on the equipment.

Because the yardstick is a peak from 1996, it does not grow as the utility grows, which is part of why the cap has drawn attention as rooftop solar spreads across the state. The honest caveat: the exact headroom left under the cap is a moving number, and the only trustworthy version of it is whatever the utility most recently reported to the Washington Utilities and Transportation Commission, the state agency that regulates the three big utilities. If a figure is not in a filing you can open, treat it as rumor.

Where the three big utilities stand

Three utilities fall under the commission's oversight across most investor-owned territory in the state. Puget Sound Energy is the largest, serving much of the Puget Sound lowlands from around Bellingham down through the suburbs east of Seattle. Avista serves the Spokane area and the eastern edge of the state, and Pacific Power covers a patchwork that includes Walla Walla and the Yakima Valley in the southern part of Washington.

Each utility tracks its own cap separately, so a reader in Spokane and a reader in Bellevue are watching different gauges at different levels. If you are served by a consumer-owned utility instead, say Seattle City Light, Tacoma Power, or a county public utility district, the statewide statute still frames net metering, but that utility's own board sets many of the terms, and you should check its tariff directly rather than the commission's docket.

What happens to the next customer after the cap

Hitting the cap does not switch the lights off on rooftop solar. What it ends is the legal guarantee that a newly signed customer gets net metering on the current terms. After that point, the compensation for a new customer is whatever the utility's tariff, the rate schedule it files with the commission, says it is. The Legislature has pushed utilities toward proposing successor arrangements rather than leaving a cliff, but the details live in each utility's filings and can differ from one service area to the next.

Math is why this matters to a prospective owner. Today's net metering typically credits the power you export at close to the full retail rate, the same price you pay for the power you buy back later. A successor rate that credits exports at a lower, wholesale-like value would lengthen the payback period on a rooftop system, sometimes by years. This desk will not put a number on that shift until a specific tariff is on the table, because the swing depends entirely on the terms filed.

Worth watching this month

1. Whether Puget Sound Energy, Avista, or Pacific Power posts an updated net metered capacity figure in a commission filing, which is the only place the real headroom shows up and is worth a quick check.

2. Any UTC docket opening a successor net metering or distributed generation tariff, since that is where a post-cap credit rate would actually be set, and it would matter more than routine rate housekeeping.

3. The next Clean Energy Transformation Act progress reporting from the state, which hints at how hard the 2045 clean-electricity deadline is pushing distributed generation policy.

4. Your own utility's net metering page for a quiet change in enrollment language, which sometimes shifts before any formal cap announcement.

5. Any bill touching RCW 80.60 when the Legislature convenes, since the cap itself is written in statute and only lawmakers can move it.