Oregon's 2021 Clean Energy Targets Act requires the state's electricity supply to be 80 percent clean by 2030, 90 percent by 2035, and 100 percent by 2040. These are among the most ambitious clean energy targets in the United States. But targets on paper and electrons on the grid are different things, and the technical challenges of integrating high levels of variable renewable energy are substantial.
TerraFuture's research team has developed a detailed hour-by-hour model of Oregon's electrical grid under various renewable energy scenarios, using 10 years of historical generation, demand, and weather data to stress-test the system under real-world conditions. Our analysis identifies both the opportunities and the bottlenecks that will determine whether Oregon meets its clean energy commitments.
Current State of the Grid
Oregon's electricity generation in 2024 was approximately 48,200 gigawatt-hours. Hydropower contributed 42 percent, natural gas 18 percent, wind 14 percent, coal 8 percent from out-of-state contracts, solar 5 percent, and other sources including biomass and geothermal contributed the remaining 13 percent. By this accounting, Oregon's grid is already approximately 61 percent clean, giving it a significant head start toward its 2030 target.
However, the remaining 39 percent represents the hardest portion to decarbonize. Natural gas plants currently provide essential grid services including frequency regulation, voltage support, and dispatchable capacity during winter peak demand and summer evening ramps when solar generation drops to zero.
Modeling Results
Our grid model simulated 8,760 hours per year across 10 weather years for three scenarios: a reference case maintaining current renewable build rates, a moderate acceleration achieving 80 percent renewables by 2035, and an aggressive scenario reaching 90 percent by 2035.
The moderate scenario requires approximately 4,800 megawatts of new solar capacity, 2,100 megawatts of new onshore wind, and 2,400 megawatts of battery storage with an average duration of 4 hours. The total capital investment is estimated at 11.2 billion dollars over 10 years, though declining technology costs could reduce this figure by 15 to 25 percent.
The most critical finding is that without battery storage, the grid experiences reliability shortfalls during 127 hours per year in the moderate scenario, concentrated in winter evenings when solar production is zero and wind generation is low. With 2,400 megawatts of storage, these shortfalls drop to 8 hours per year, all during extreme cold weather events. Adding demand response capacity equivalent to 15 percent of peak load eliminates remaining shortfalls entirely.
The question is not whether 80 percent renewable energy is technically feasible. Our modeling shows it clearly is. The question is whether we will make the investments in storage, transmission, and demand flexibility that make it reliable.
Transmission Constraints
Oregon's existing transmission network was built to move hydropower from the Columbia Basin to load centers in Portland and the Willamette Valley. The optimal locations for new solar development are in central and eastern Oregon, where solar irradiance is 20 to 35 percent higher than west of the Cascades but transmission capacity is limited.
Our analysis identifies three critical transmission corridors that require upgrades: the Central Oregon to Portland path, currently constrained at approximately 1,800 megawatts; the Southern Oregon to Willamette Valley path at 1,200 megawatts; and the Columbia Gorge east-west path at 2,400 megawatts. Combined upgrade costs are estimated at 1.8 to 2.6 billion dollars.
Without these upgrades, curtailment of renewable generation, where available clean energy is wasted because it cannot reach demand centers, reaches 12 percent in our moderate scenario by 2032. With upgrades, curtailment drops to 2.4 percent, a level considered economically acceptable by grid planners.
Cost Implications
Under the moderate scenario, Oregon's average retail electricity rate increases from the current 11.2 cents per kilowatt-hour to an estimated 13.8 cents by 2035, a 23 percent increase in nominal terms. Adjusted for inflation, the real increase is approximately 8 percent.
However, this cost increase is offset by several factors not captured in the retail rate: avoided health costs from reduced air pollution estimated at 180 million dollars annually, reduced price volatility compared to natural gas generation, and local economic benefits from clean energy jobs and investment.
Policy Recommendations
TerraFuture is submitting this analysis to the Oregon Public Utility Commission and the state legislature with three recommendations. First, establish a state-level energy storage target of 2,000 megawatts by 2030. Second, streamline permitting for transmission upgrades on existing rights-of-way. Third, expand demand response programs through utility rate design that rewards flexible consumption.
Oregon has the resources, both natural and institutional, to lead the clean energy transition. The grid analysis shows the path is clear. What remains is the political will to walk it.
