Obsidian Renewables LLC recently broke ground on a portion of its planned 400-MW Obsidian Solar Center in Lake County, Ore., with a potential 50-MW flow battery storage system, David Brown, a company co-founder and senior principal, said in an interview.

It is the largest solar project under development in Oregon, nearly seven times the capacity of the state's biggest operating solar farm, according to S&P Global Market Intelligence data. And it marks a milestone in the state's renewable-energy transition, as developers of large-scale solar farms, including with battery storage, build new projects across Oregon as part of the state's accelerating efforts to decarbonize its power supplies. New facilities are appearing in central and eastern Oregon, in counties like Morrow, and in rainy western counties, like Clackamas.

"The tax law forced me to start," Brown said in reference to the U.S. government's step down of investment tax credits for solar and solar-charged batteries. Obsidian started work at the end of 2019 in order to qualify it for incentives amounting to 30% of project cost.

While Obsidian still lacks a power purchase agreement, Brown sees encouraging signs in the Pacific Northwest's embrace of renewables and the emergence in Oregon of power-hungry data centers from tech firms seeking zero-carbon electricity.

But Brown's bet is based foremost on the retirement of coal plants throughout the region.

Portland General Electric Co. will retire its 585-MW Boardman power plant in eastern Oregon, the state's only coal-fired facility, at the end of 2020. In Washington, TransAlta Corp. plans to shut down half of its 1,340-MW Centralia coal facility in Lewis County in December 2020 and the other half in 2025, ending coal generation in that state.

In Montana, Talen Energy Corp. recently shuttered two of four units at the Colstrip coal plant, which is co-owned by a collection of Northwest utilities, while Idaho Power Co. is retiring several coal generating stations.

Oregon solar pipeline

With the coal plant shutdowns and Oregon's requirement for utilities to source 50% of their retail electric sales from renewable resources by 2040, not including large-scale hydropower, solar development in the state has accelerated. More than two dozen large-scale solar photovoltaic, or PV, projects are under development in Oregon, totaling nearly 1,500 MW, S&P Global Market Intelligence data shows.

Roughly 614 MW of utility-scale and distributed PV capacity was operational in Oregon through the third quarter of 2019, according to the Solar Energy Industries Association.

Avangrid Renewables LLC, which sells power to Apple Inc. from its 56-MW Gala Solar Plant (Prineville Solar), the state's largest operating PV project, is moving quickly on bigger solar projects.

The developer, an affiliate of Avangrid Inc., plans to start construction on a 162-MW solar farm in Gilliam County at the end of 2020 or early 2021, its 11th renewable-energy project in Oregon. Sited next to its Montague Wind Facility (Leaning Juniper III), which also sells power to Apple, the still-unnamed project is underpinned by a 15-year power purchase agreement with Portland General Electric, or PGE, announced Feb. 11.

The investor-owned utility is buying the power for participants in its voluntary Green Future Impact program, which offers 100% renewable electricity. Customers include the state's most populous cities and counties, including Portland, as well as major corporations Adobe Inc. Comcast Corp. and Daimler Trucks North America LLC, a subsidiary of German auto giant Daimler AG.

"Given our company's long history in the Pacific Northwest, we are proud to play a key role in delivering more renewable electricity to forward-thinking commercial energy customers," Alejandro de Hoz, president and CEO of Avangrid Renewables, said in a news release.

Avangrid's proposed Bakeoven Solar Project, under review by the Oregon Department of Energy's facilities siting division, would combine 100 MW of lithium-ion or flow batteries with 303 MW of solar generation capacity in Wasco County. While it has not announced a customer, Avangrid plans to begin construction as soon as June 2020 and complete the project by 2025.

Moving aggressively

PGE last year announced agreements with NextEra Energy Resources LLC, a subsidiary of NextEra Energy Inc., to purchase 300 MW of wind, 50 MW of solar and 30 MW of battery storage from the Wheatridge Renewable Energy Facility starting in December 2021.

Located in Morrow County, home of the Boardman coal plant, NextEra's hybrid complex has additional uncommitted capacity at the Wheatridge Solar & Battery Storage Facility, with 150 MW of solar and 30 MW of storage, and the 500-MW Wheatridge Wind Energy Facility.

PGE is also purchasing solar from a 10-MW plant completed in December, part of a contracted 40-MW solar portfolio acquired by Soltage LLC.

Developer US Solar Fund PLC owns four Oregon solar projects currently under construction, totaling 61 MW, the company announced Feb. 27. Contracted with an undisclosed "investment-grade offtaker," the projects are scheduled for completion in the second half of this year.

Also under construction is Invenergy LLC's 75-MW Boardman Solar Energy Facility in Morrow County, according to an official at the Oregon Department of Energy. EcoPlexus Inc.'s proposed 63-MW Madras Solar Energy Facility in Jefferson County, with up to 240 MWh of energy storage, and EDP Renewables North America LLC's 60-MW Blue Marmot Solar Energy Facility in Lake County are under review.

EDP Renewables is a subsidiary of EDP - Energias de Portugal SA.