Net Metering in Washington: How Solar Credits Work

Net metering is the billing mechanism that allows Washington solar system owners to receive credit for surplus electricity sent to the utility grid. This page covers how the credit calculation works, which utilities must comply, what state law requires, and where the policy's practical boundaries lie. Understanding net metering is essential for accurately estimating the financial return on any grid-tied solar installation in Washington State.

• Definition and scope
• Core mechanics or structure
• Causal relationships or drivers
• Classification boundaries
• Tradeoffs and tensions
• Common misconceptions
• Checklist or steps (non-advisory)
• Reference table or matrix

Definition and scope

Net metering in Washington is governed primarily by RCW 80.60, the state's net metering statute, which obligates qualifying electric utilities to offer net metering service to eligible customer-generators. Under RCW 80.60.010, a "customer-generator" is defined as a utility customer who operates an electrical generating facility with a capacity of no more than 100 kilowatts (kW) that uses solar, wind, hydropower, or biogas as its fuel source. The 100 kW threshold applies per customer account, not per physical site.

The Washington Utilities and Transportation Commission (UTC) regulates investor-owned utilities subject to net metering rules, including Puget Sound Energy and Pacific Power. Publicly owned utilities — municipal utilities and public utility districts (PUDs) such as Seattle City Light, Snohomish County PUD, and Clark Public Utilities — operate under separate governance structures but are still required by RCW 80.60 to offer net metering.

Scope and coverage: This page applies specifically to net metering policy within Washington State under RCW 80.60 and associated Washington UTC rules. Federal interconnection standards under FERC Order 2222 and IEEE 1547-2018 govern technical grid interconnection but are not covered in full detail here. Net metering rules for systems larger than 100 kW, virtual net metering, and community solar crediting operate under different statutory frameworks and are not covered by the residential net metering provisions described on this page. Community solar programs in Washington are addressed separately at Washington Community Solar Programs.

Core mechanics or structure

Net metering works by measuring the difference between electricity consumed from the grid and electricity exported to the grid over a billing period. When a solar system produces more power than the home or business consumes at any given moment, the excess flows onto the grid and the meter effectively runs backward — or, in the case of digital smart meters, registers a separate export reading.

Washington utilities calculate net metering credits on a kilowatt-hour (kWh) basis. Exported kWh offset consumed kWh at the retail rate during the same billing period. If exports exceed consumption within a monthly billing cycle, the surplus rolls over as a kWh credit to the following month. Unlike some states, Washington does not require utilities to pay cash for surplus credits at year's end; instead, any remaining credits are typically extinguished at the end of a 12-month cycle, though utility-specific tariffs govern the exact treatment.

The net metering measurement cycle and true-up schedule vary by utility. Puget Sound Energy, for example, applies a monthly netting approach with annual true-up, while some PUDs apply different billing period structures under their own tariff filings. Reviewing the specific tariff document on file with the UTC or the relevant PUD's board-approved rate schedule is the authoritative source for each utility's exact mechanics.

For a foundational explanation of how solar energy systems generate and deliver electricity before metering applies, see How Washington Solar Energy Systems Work: Conceptual Overview.

Causal relationships or drivers

Washington's mandatory net metering obligation exists because RCW 80.60 was enacted to lower economic barriers to distributed renewable generation. The statute reflects a legislative finding that distributed solar reduces peak load demand and supports the state's clean energy goals under the Washington Clean Energy Transformation Act (CETA), RCW 19.405, which requires all electricity utilities to achieve 100% clean energy by 2045.

Retail-rate crediting is the key financial driver that makes net metering attractive. Because exported kWh are credited at the same rate the customer pays to consume electricity — rather than at the lower wholesale generation rate — the effective value of solar production is maximized when consumption and production align. A Washington residential customer paying $0.11 per kWh (a typical rate tier; actual rates vary by utility and tariff class) receives $0.11 of credit per exported kWh, whereas the utility's avoided wholesale cost for the same energy is substantially lower.

The 100 kW capacity cap is a policy boundary, not a technical one. It is set at the statutory level to limit net metering's scope to small customer-generators, reducing potential cross-subsidization concerns that arise when larger generators receive retail-rate credits for wholesale-scale production. For commercial or agricultural operations with larger systems, different interconnection and compensation mechanisms apply. Those contexts are covered at Washington Solar Energy for Commercial Properties and Washington Solar Energy for Agricultural Operations.

The regulatory framework shaping net metering decisions is detailed further at Regulatory Context for Washington Solar Energy Systems.

Classification boundaries

Washington net metering involves three distinct classification axes that determine which rules apply:

1. Utility type:
- Investor-owned utilities (IOUs): Regulated by the Washington UTC. Must follow UTC-approved tariffs. Puget Sound Energy and Pacific Power fall here.
- Public utility districts and municipal utilities: Governed by locally elected boards. Subject to RCW 80.60 but not UTC rate regulation. Tariff structures are board-approved.
- Electric cooperatives: Subject to RCW 80.60 net metering obligations.

2. System capacity:
- Systems at or below 100 kW AC qualify for standard net metering under RCW 80.60.
- Systems above 100 kW must negotiate separate interconnection agreements; standard net metering credits do not apply.

3. Generation technology:
- Eligible technologies: solar photovoltaic, wind, hydropower, and biogas.
- Fuel cells, conventional generators, and non-renewable sources are not eligible under RCW 80.60.

Battery storage systems paired with solar do not alter net metering eligibility but affect how export is measured. Only electricity that physically flows onto the grid is eligible for net metering credits; electricity stored in and later discharged from a battery is credited only if it ultimately exports to the grid through the bidirectional meter. Washington Solar Battery Storage Options covers storage integration in detail.

Tradeoffs and tensions

Retail-rate crediting vs. cost allocation:
The central tension in net metering policy is whether crediting solar exports at the full retail rate accurately reflects the value those exports provide to the grid. Utilities argue that retail rates include fixed infrastructure costs (poles, wires, billing systems) that solar customers avoid paying when they offset consumption with exports. Ratepayer advocates and solar proponents argue that distributed solar provides grid services — peak shaving, reduced transmission losses, deferred capacity investment — that justify retail-rate compensation. This debate is active at the Washington UTC and in utility integrated resource planning processes.

Aggregate program caps:
RCW 80.60 previously included a provision allowing utilities to limit net metering enrollment once aggregate capacity reached 0.5% of the utility's 1996 peak demand. Legislative amendments have modified this structure over time, but the underlying tension between open-ended enrollment and utility resource planning remains a policy consideration.

Annual credit forfeiture:
Customers whose systems are oversized relative to annual consumption may generate surplus credits that are extinguished at the 12-month cycle. This represents a real financial cost of over-sizing, which is why system sizing relative to actual load is a technical consideration — not a marketing preference. Washington Solar System Sizing Guide addresses this directly.

Rate design evolution:
As Washington utilities file new rate cases with the UTC, time-of-use (TOU) rate structures are increasingly under consideration. If TOU rates are applied to net metering, the value of exported solar may vary depending on when surplus production occurs, creating new optimization challenges for system owners.

Common misconceptions

Misconception: Net metering means free electricity.
Correction: Net metering offsets consumption charges. Customers typically still pay fixed monthly service charges, demand charges (in some commercial tariffs), and any consumption that exceeds solar production. The word "net" refers to the mathematical difference, not a zero-cost outcome.

Misconception: Excess credits roll over indefinitely as cash.
Correction: Under RCW 80.60, surplus kWh credits carry forward month to month but are extinguished at the end of the 12-month period. They do not convert to cash payments unless a specific utility tariff provides otherwise. No Washington IOU tariff approved by the UTC currently requires cash buyback of surplus annual credits.

Misconception: All Washington utilities use the same net metering rules.
Correction: While RCW 80.60 establishes a statewide floor, the precise billing cycle, true-up date, rate structure, and interconnection fees vary by utility. A customer on a Snohomish County PUD rate schedule operates under different tariff specifics than a Puget Sound Energy customer.

Misconception: A bidirectional meter is optional.
Correction: A bidirectional (or two-register) meter is a technical prerequisite for net metering. Most Washington utilities require the customer to coordinate meter replacement or upgrade as part of the interconnection application process before net metering billing can begin. Interconnection requirements are addressed at Washington Utility Interconnection Requirements.

Misconception: Net metering applies automatically once solar is installed.
Correction: Net metering billing does not activate until the utility has completed its interconnection review, issued permission to operate (PTO), and installed the appropriate meter configuration. Operating a grid-tied inverter before PTO is issued violates utility interconnection agreements and NEC/IEEE 1547 safety requirements.

Checklist or steps (non-advisory)

The following sequence describes the procedural stages a Washington customer-generator typically moves through to activate net metering. This is a descriptive framework, not professional advice.

1. Confirm utility net metering tariff — Obtain the current net metering tariff or rate schedule from the serving utility. For UTC-regulated utilities, tariff documents are publicly available on the UTC Tariff System.

2. Determine system capacity eligibility — Verify that the proposed system does not exceed 100 kW AC nameplate capacity per the RCW 80.60 definition.

3. Submit interconnection application — File a formal interconnection application with the utility before installation commences. Utilities typically require a completed application, single-line diagram, equipment specifications, and site plan.

4. Obtain building and electrical permits — Local authority having jurisdiction (AHJ) building and electrical permits are required. Permit processes are addressed at Permitting and Inspection Concepts for Washington Solar Energy Systems.

5. Complete installation to code — Installation must comply with the 2023 National Electrical Code (NEC), NFPA 70-2023, Washington State electrical code amendments, and IEEE 1547-2018 interconnection standards.

6. Pass inspections — Local electrical and building inspections must be passed and documented before energization.

7. Receive utility permission to operate (PTO) — The utility conducts its own review (which may include a site visit or documentation review) and issues PTO.

8. Meter configuration — Utility installs or programs bidirectional metering. Net metering billing begins on the first full billing cycle after meter configuration.

9. Confirm tariff enrollment — Verify with the utility that the account has been enrolled in the net metering rate schedule and that the billing cycle and true-up date are correctly recorded.

Reference table or matrix

Washington Net Metering Key Parameters

Utility-Specific Net Metering Snapshot (Washington)

Tariff specifics change with rate case filings. Customers should verify current tariff documents directly with their utility or the UTC tariff database.

For a broader orientation to solar policy and incentive programs in Washington, the Washington Solar Authority home provides navigational context across all relevant topics.

References

• RCW 80.60 — Net Metering (Washington State Legislature)
• RCW 19.405 — Washington Clean Energy Transformation Act (Washington State Legislature)
• Washington Utilities and Transportation Commission (UTC)
• Washington UTC Tariff System — Electric Utilities
• IEEE 1547-2018 — Standard for Interconnection and Interoperability of Distributed Energy Resources
• FERC Order 2222 — Participation of Distributed Energy Resource Aggregations
• NFPA 70 — National Electrical Code (NEC), 2023 edition