Washington Supreme Court Reinstates Electrification Legislation
On September 17, 2026, the Washington Supreme Court issued a split decision in Climate Solutions v. State of Washington striking down Initiative 2066, a 2024 voter-approved initiative intended to preserve the use of natural gas in the state by, among other things, barring certain laws that discourage use of gas and/or that promote electrification. In doing so, the Court effectively reinstated decarbonization legislation enacted in 2024 to hasten the state's transition from natural gas to electricity. The Climate Solutions decision will likely increase the demand for electricity in the state at a time when regional electricity demand is already skyrocketing due in part to the accelerating development of data centers.
For developers of electric generating facilities (mostly wind and solar, as a practical matter), the ruling is good news. For data centers and other large loads, it increases both the importance of securing power early and the risk of greater regulatory scrutiny with respect to the use of gas. For building owners and developers, the decision restores local and state flexibility to adopt building policies that promote electrification or discourage the use of natural gas in new construction.
How Washington Got Here
In 2021, the Washington Legislature enacted the Climate Commitment Act (CCA), creating a Cap-and-Invest program designed to greatly reduce the emission of greenhouse gases (GHGs) in the state. In 2024, the Legislature followed that with the Washington Decarbonization Act for Large Combination Utilities (Decarbonization Act). RCW 80.86 et seq. The Decarbonization Act established a planning framework intended to transition "large combination utilities" (defined to include only the state's largest electric and gas utility, Puget Sound Energy) toward increased use of electricity and away from long-term natural gas use.
Following the Decarbonization Act, initiative campaigns were launched against both the CCA and the Decarbonization Act. In November 2024, the anti-CCA initiative failed by a large margin, but the anti-Decarbonization Act initiative (I-2066) prevailed. It sought to preserve retail customer access to natural gas and prevent policies that discourage its use. The initiative required gas companies, large combination utilities, and municipal gas providers to continue serving eligible gas customers, limited the Washington Utilities and Transportation Commission's (WUTC) ability to approve plans restricting gas access, removed a zero-emission goal from the state energy code, constrained the Washington State Building Code Council from imposing rules restricting natural gas use, and restricted local governments and air agencies from discouraging gas use.
A coalition led by Climate Solutions challenged I-2066, arguing that it addressed multiple subjects, failed to disclose all subjects in its title, and amended existing laws without setting out the affected provisions in full, in violation of the Washington Constitution. The King County Superior Court agreed and invalidated I-2066, and the Washington Supreme Court affirmed.
Why the Supreme Court Struck It Down
In a 6-3 decision, the Washington Supreme Court affirmed the lower court's invalidation of I-2066 solely for violating the state constitution's single-subject rule (Article II, Section 19). It reasoned that the four policies addressed in the initiative (preserving natural gas service, restricting local air quality regulation, changing state building and energy codes, and repealing the Decarbonization Act's severability clause) lacked "rational unity" (i.e., they were not sufficiently related to each other). As a result, the Court concluded that it could not determine which of the four policies the voters would have approved separately and therefore struck down the entire initiative.
Justice Mungia's dissent took a more surgical approach. He would have rejected the provisions restricting local governments and air agencies, along with the repeal of the Decarbonization Act's severability clause but would have upheld the remainder of the initiative as a sufficiently cohesive effort to preserve access to natural gas. Although the majority disagreed with this approach, it implicitly left the door open to a future initiative that more clearly defines how its provisions hang together as a unit.
What Does the Decision Mean for Washington's Climate Goals?
The ruling restores several regulatory tools that the state can use to meet its climate goals. The WUTC can again consider integrated system plans submitted by large combination utilities that encourage movement from gas to electric service, including scenarios that achieve GHG emission reductions.
The decision also restores the state energy code's goal of helping achieve zero fossil-fuel greenhouse-gas-emission homes and buildings by 2031, along with the Washington State Building Code Council's authority to adopt code provisions promoting electrification.
Local governments likewise are no longer barred from taking "any action" that discourages gas use. They therefore retain greater flexibility to adopt electrification incentives, renewable-ready construction requirements, and policies favorable to the deployment of distributed energy resources.
What Does It Mean for Renewable Developers?
The restored governmental authorities may produce clearer procurement signals. If utilities anticipate additional electric load from buildings (in addition to the electrification of transportation), they may accelerate requests for renewable generation, storage, and demand-management resources. Restored building-code authority may support all-electric construction, including behind-the-meter solar, community solar, storage, and building-integrated renewables serving new construction. Local incentives and renewable-ready requirements could also create additional opportunities in distributed-generation markets.
But the Court's decision does nothing to overcome the longstanding constraints that are plaguing clean energy developers—siting delays, interconnection queues, and transmission constraints.
What Does It Mean for Data Centers?
The Court's decision could also affect data center development. By allowing Washington's pro-electrification policies to proceed, the ruling has the potential to lead to more new electric generating facilities and accompanying energy storage. But that can only happen if solutions are found to the same bottlenecks facing the energy development community—siting, interconnection, and transmission capacity.
The ruling may also affect data centers that plan to use natural gas for on-site backup generation. To the extent that the state transitions away from the use of gas in buildings, it's logical to expect that more gas will become available for data centers. But reduced demand for gas in buildings could also leave fewer customers paying for pipelines and other infrastructure, potentially undermining future investment in those facilities, so data center developers should not assume that lower overall gas demand will necessarily translate into cheaper or more reliable gas service for their facilities. Separately, local air agencies and building-code authorities may have greater freedom to regulate the permitting, installation, and operation of natural gas or diesel backup generators associated with data center buildings because I-2066's restrictions no longer apply.
What Does It Mean for Property Owners and Developers?
The decision restores the state's zero-emission building goal and removes I-2066's restrictions on state and local rules that prohibit, penalize, or discourage natural-gas use for any form of heating or for appliances or equipment in any building. This means that property owners and developers may face additional building standards that promote electric heating and appliances or make natural-gas systems more difficult or expensive to install, particularly in new construction and major renovations. The ruling does not itself prohibit natural gas in buildings, but it restores the authority of the Washington State Building Code Council and local governments to pursue electrification through future code changes. Developers should monitor upcoming code cycles and preserve flexibility in projects that may be permitted or constructed over several years.
Bottom Line
The Climate Solutions decision restores governmental authority to transition from natural gas to electricity, potentially boosting the demand for clean electricity. But that demand can only be met if—you guessed it—those stubborn siting, interconnection, and transmission problems can be solved. In the meantime, the debate over the role of natural gas in the state is far from over. The Court's 6-3 majority struck down I-2066, but its reasoning left room for a more carefully tailored initiative.
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Molly Barker is counsel, Clayton Graham is a partner, Megan Raymond is an associate, and Craig Gannett is senior counsel in DWT's Seattle office. We'll be tracking these matters closely and would welcome the opportunity to discuss your questions, concerns, and insights at your convenience. Please reach out to the authors or another member of our energy, natural resources & environmental team. To stay informed, sign up for our alerts.