How Much Is Solar in Seattle, WA? $2.55/W, 18.6-Yr Payback

In Seattle, WA, an 8 kW system at $2.55/W produces about 1,086 kWh per kW and pays back in roughly 18.6 years at 14.09¢/kWh with the federal credit at $0.

Updated September 2026 · Source: EIA Electric Power Monthly Table 5.6.A (July 2026 data) · next EIA update ~Oct 23

On this page: CalculatorTableHow we calculatedSources

Washington is not one solar market

Across the 6 Washington cities with their own modeled figures, production spans 32% — Everett at 999 kWh per kW to Yakima at 1,320. Every column except production is identical down this table: same 14.7¢/kWh retail rate, same export regime, same $2.55/W installed cost. The payback differences are caused by weather and nothing else.

Against the state figure, Seattle is the reference point: our Washington page uses 1,045 kWh per kW, which is this city. The value of this page is the comparison above, not a different headline number.

The seasonality nobody prices in

Seattle’s annual figure is misleading in an unusual way: the output is not uniformly poor, it is violently seasonal. At 47.6° north the summer days are very long and often genuinely clear, and June through August production per kilowatt is competitive with far sunnier places. November through February is close to nothing.

That shape is why full-retail net metering matters so much here. Washington still credits exports at the retail rate under RCW 80.60, which lets a Seattle array bank a large summer surplus against a dark winter. Under net billing the same hardware would be far less attractive, because the summer surplus — the bulk of the annual output — would be sold at a fraction of its value instead of carried forward.

Your utility, officially

Washington’s average residential rate is 14.7¢/kWh, but the bill in Seattle comes from City of Seattle - (WA) at 14.09¢ — 4.2% below the state figure. These are the residential figures Seattle’s utility reported to the U.S. Energy Information Administration on Form EIA-861 for 2024 — computed as revenue ÷ sales from the official file, not estimated:

How exports are treated matters as much as the headline price: City of Seattle is modeled here under full-retail net metering , and that treatment is baked into every payback figure on this page.

Seattle City Light is not a company you can compare against competitors — it is a department of city government, founded by Seattle voters in 1902, and it bills all 459,964 residential customers inside its territory at an average of 14.09¢/kWh per the 2024 EIA-861 file. Being municipal matters more here than almost anywhere else on this site, because Washington’s statewide export rules formally bind investor-owned, state-regulated utilities; a city-owned utility writes its own solar terms. In Seattle’s case, the terms it has written are good, and unusually well documented.

City Light’s own solar page (seattle.gov ) lays out the deal: systems up to 100 kW AC fall under its net metering program, exports are metered in real time, and credits are valued at your retail rate and applied automatically, so you pay only for net usage each billing period. Surplus in a strong month carries forward as a credit balance against future bills — the summer-banking mechanism this page’s seasonality section explains, offered here by a utility that never had to. City Light even allows meter aggregation, letting excess generation offset a second meter on the same account and parcel, which is rare and occasionally very useful for a house with a detached workshop or an accessory dwelling.

Now the part that deserves your attention before you sign a twenty-year bet. The same official page opens with a program note: City Light “has begun planning the next phase of its net metering program,” with a stated goal of giving customers and installers at least six months’ notice before proposed changes take effect. That is not a rumor; it is the utility telling you, in its own words, that today’s retail-rate crediting is under review. Nothing published there says what the successor looks like, and we will not guess. It does mean a Seattle solar decision made in 2026 should be sized for self-consumption first, with export value treated as a bonus that may be restructured.

One data footnote: the 2024 EIA net-metering file contains no residential net-metering row for City Light, so unlike Tacoma next door we cannot report how many Seattle roofs are already connected from federal data. The program’s existence is verified on the utility’s own site; the adoption count is a number Seattle’s utility did not hand the federal government that year.

Source: EIA Form EIA-861, 2024 final release , accessed 2026-09-02. Average price is total residential revenue divided by total residential sales for the year — your own rate depends on your tariff and usage tier.

Who else serves the metro

Even though the City of Seattle’s own utility covers a single-county EIA-861 territory, that county still lists other systems nearby: Puget Sound Energy at 14.6¢, the City of Tacoma’s utility at 10.8¢, and the Chelan County PUD at just 3.7¢. Against Seattle’s 14.09¢, that’s a swing from about 0.5¢ above to about 10.4¢ below, driven partly by Chelan’s hydropower-based pricing — too large for a payback built on Seattle’s rate to hold anywhere else on that list, especially since export terms also vary by utility. Washington’s July 2026 state average, 14.71¢, is a later number computed differently from these 2024 figures. A ZIP code, not a Seattle mailing address, determines which utility serves a property.

The exact answer is a ZIP question, not a city question: look up your utility by ZIP . Candidates: utilities EIA-861 lists in 1 service county of the metro’s main utility; prices are 2024 revenue ÷ sales from the official file.

The policy risk is the real risk in Seattle

RCW 80.60 is full retail in statute, but several Washington utilities have already reached the 4% cumulative capacity cap that triggers a successor tariff, and practice across the state is now mixed. Because Seattle’s economics lean so heavily on banking summer surplus, a move to net billing would hurt more here than in a sunnier, flatter-output market.

Seattle City Light is a municipal utility, which puts it outside the state-regulated framework entirely. If that is your provider, confirm its own net-metering terms rather than assuming the statutory rule applies to you.

What Washington pays Seattle for exported power

Washington credits exported power at the retail rate under RCW 80.60 , so a kilowatt-hour a Seattle array sends to the grid is worth the same as one you buy. That is the best case for solar economics and it is why the payback above is what it is.

It is also the assumption most likely to change. Twenty-two states have already moved to net billing. If Washington did the same on typical terms, this system would take about 28.6 years instead of 18.6 — 10.0 years’ difference from a policy change, with no change to the hardware and none to Seattle’s weather.

Full retail in statute, but several utilities have hit the 4% cap and moved to successor tariffs, so practice is mixed.

Sources and method

• Production: modeled with PVGIS v5.2 PVcalc (European Commission JRC) using the PVGIS-NSRDB radiation database — the same NREL satellite dataset PVWatts draws on for the Americas. Assumptions: 4 kWp, standard c-Si, 14% system loss, roof mounting, 20-degree tilt, due south, horizon shading on. The 1,086 kWh per kW figure for Seattle is a modeled location point, not an interpolation from the Washington average. PVGIS is free to use with JRC attribution requested; the underlying NSRDB is public domain (NREL/DOE).
• Real-roof derate: a separate 10% deduction for azimuth, pitch and shading, applied in the shared model rather than folded into the production data — so you can adjust it if your roof is genuinely unobstructed.
• Electricity rate: U.S. Energy Information Administration, average price by state . This is Washington’s residential average; EIA does not publish a Seattle figure, so the state rate is used and labeled as such.
• Export rules: RCW 80.60 , from our Washington state page and the shared export-rules dataset behind it.
• State average rate: EIA Table 5.6.A, July 2026 data (released Sep 2026), used for every state-average comparison on this page.
• Payback model: shared with the solar savings calculator and the state pages — 2.5%/yr utility inflation, 0.5%/yr degradation, $150/yr running costs, one $2,000 inverter replacement in year 14, federal credit $0. The rest of the toolset — battery, sizing, financing — is under all calculators .
• Incentives: DSIRE . City and utility programs change more often than state ones — check yours directly.

Electricity rate, export regime, production figure and installed cost on this page were last verified on 30 August 2026. Export credits reset on annual tariff cycles and incentive budgets run out mid-year, so treat every figure as a snapshot at that date and confirm current terms before acting. Nothing here is tax or financial advice.

Frequently asked questions

Sources: U.S. Energy Information Administration (EIA) electricity rates · DSIRE incentive records · public IRS/OBBBA guidance. Figures are modeled estimates, not quotes or tax advice. See our methodology.

Compare with the rest of Washington

• Solar panel cost in Washington — The statewide picture: Washington’s rate, incentives, export rules and the 1,045 kWh per kW average this page corrects.
• Solar panel cost in Yakima — 1,320 kWh per kW and a 15.1-year payback — better than Seattle on identical hardware.
• Solar panel cost in Spokane — 1,195 kWh per kW and a 16.5-year payback — better than Seattle on identical hardware.
• Solar panel cost in Tacoma — 1,046 kWh per kW and a 18.5-year payback — worse than Seattle on identical hardware.
• Solar panel cost in Bellingham — 1,022 kWh per kW and a 18.9-year payback — worse than Seattle on identical hardware.
• Solar panel cost in Everett — 999 kWh per kW and a 19.2-year payback — worse than Seattle on identical hardware.
• Solar panel cost in Portland — 1,083 kWh per kW in Oregon — the closest production match to Seattle in our data.
• Solar panel cost in Syracuse — 1,114 kWh per kW in New York — the closest production match to Seattle in our data.
• All city solar figures — The 66 US cities with their own modeled production data, and the spreads between them.