A new 50-year operating license issued in 2008 from the Federal Energy Regulatory Commission for the Baker River Project – the largest hydropower asset owned by Puget Sound Energy (PSE) – called for flow releases from the Lower Baker Dam to improve movement of migratory fish. To help PSE optimize the use of the Baker River water resource for power generation while accommodating the flow release requirement, Black & Veatch designed a new powerhouse and other hydropower components as part of the design-build team for the Lower Baker Unit 4 Powerhouse project.
Completed in 2013, the new power facility houses a single turbine-generator unit with a capacity of 30 megawatts (MW), increasing the installed capacity of the Lower Baker development to 109 MW. As a whole, the Baker River Project consists of two hydropower developments, Lower Baker and the 91 MW Upper Baker facilities.
A New Powerhouse
Due to the size and hydraulic capacity of the new powerhouse unit, it is able to generate power from flow releases that are below the operating range of the existing 79 MW turbine-generator unit at Lower Baker. This generation is a significant benefit to the project and would not be possible without the construction of the new powerhouse facility.
In addition to generating power, the new powerhouse, operating in concert with the existing unit, allows PSE to closely regulate and maintain river flows through the Lower Baker Dam to better accommodate the needs of fish and optimize the water resource.
Black & Veatch, the project’s engineer of record on the PCL Construction design-build team, also designed a new 12-foot diameter, 1,000-foot long pressure tunnel from the existing surge tank to the new powerhouse. The project features also include the design and construction of a penstock and bifurcation; synchronous bypass valve; draft tube gates; installation of owner-furnished equipment; and startup and commissioning services.
The new powerhouse, built approximately 400 feet downstream of the existing powerhouse site, is a single-unit, subterranean, reinforced concrete structure. The work also included governor and control upgrades for the existing unit at Lower Baker.
The new powerhouse allows PSE to closely regulate river flows to better accommodate the needs of fish and optimize the water resource.