Pacific Northwest–Pacific Southwest Intertie

Pacific Northwest–Pacific Southwest Intertie
Name	Pacific Northwest–Pacific Southwest Intertie
Country	United States
Status	Operational
Start	Bonneville Power Administration
Finish	Los Angeles Department of Water and Power
Owner	Federal Energy Regulatory Commission-regulated utilities
Length km	1700
Capacity MW	4800

Contents

Pacific Northwest–Pacific Southwest Intertie The Pacific Northwest–Pacific Southwest Intertie is a high-voltage alternating current and direct current transmission corridor linking Bonneville Power Administration, Pacific Gas and Electric Company, Los Angeles Department of Water and Power, Bonneville Dam, and other utilities across the western United States, designed to move bulk hydroelectricity and thermal generation between the Columbia River, Sierra Nevada, and Los Angeles Basin. The project facilitates seasonal transfers among regions governed by North American Electric Reliability Corporation standards and coordinated through entities such as the California Independent System Operator and the Western Electricity Coordinating Council, enabling transfers tied to market signals from California Energy Commission policies and federal statutes like the Federal Power Act.

Overview and Purpose

Constructed to interconnect resources in the Pacific Northwest and Southern California, the intertie supports reliability for load centers such as San Francisco, San Diego, and Los Angeles while integrating generation from the Columbia River Basin, Sacramento River, and thermal plants in the Central Valley. It serves as an operational asset for balancing obligations under the North American Electric Reliability Corporation and market arrangements administered by the California Independent System Operator and Bonneville Power Administration, enabling power trades influenced by decisions at the Federal Energy Regulatory Commission, U.S. Department of Energy, and state agencies like the California Public Utilities Commission.

Planning began mid-20th century amid postwar development linked to projects such as Bonneville Dam, Shasta Dam, and the expansion by municipal utilities including the Los Angeles Department of Water and Power and investor-owned companies like Pacific Gas and Electric Company and Sacramento Municipal Utility District. Major construction phases involved cooperation among federal agencies like the Bureau of Reclamation, regional entities including Bonneville Power Administration and Western Area Power Administration, and corporate stakeholders such as Southern California Edison and Sacramento Municipal Utility District, with regulatory oversight from the Federal Power Commission and later the Federal Energy Regulatory Commission. Key milestones coincide with legislative acts such as amendments to the Federal Power Act and policy shifts following events like the 1973 oil crisis and deregulation trends associated with the Energy Policy Act of 1992.

The corridor comprises alternating current lines, high-voltage direct current components, and series capacitors spanning mountain passes and desert stretches between the Columbia River Basin and Los Angeles Basin, traversing transmission rights-of-way near the Sierra Nevada, Cascade Range, and the Mojave Desert. Major nodes include substations operated by Bonneville Power Administration, Pacific Gas and Electric Company, Southern California Edison, and municipal systems such as the Los Angeles Department of Water and Power and Sacramento Municipal Utility District, with interconnections to balancing authorities including the California Independent System Operator and North American Electric Reliability Corporation. Engineering elements feature towers and conductors supplied by industrial firms like General Electric, Siemens, and ABB Group, and maintenance coordinated via regional companies including Bonneville Power Administration and Western Electricity Coordinating Council.

Operational capacity has varied with upgrades, reaching several thousand megawatts for long-term transfers and higher short-term swing through coordinated dispatch among California Independent System Operator, Bonneville Power Administration, Southern California Edison, and Pacific Gas and Electric Company. The intertie supports energy arbitrage driven by market prices overseen by the California Public Utilities Commission and federal policies from the Department of Energy, and it plays a role in contingency planning under North American Electric Reliability Corporation criteria and seasonal water management decisions tied to the Bureau of Reclamation and U.S. Army Corps of Engineers. Modernization projects have included converters, series compensation, and conductor replacements funded or implemented by entities such as Federal Energy Regulatory Commission-regulated utilities and regional transmission organizations.

Environmental reviews have involved the National Environmental Policy Act process, consultations with agencies like the U.S. Fish and Wildlife Service and Environmental Protection Agency, and assessments of impacts on corridors near the Sierra Nevada and Columbia River ecosystems, including migratory fish concerns linked to Bonneville Dam. Permitting required coordination across state agencies such as the California Public Utilities Commission and federal regulators including the Federal Energy Regulatory Commission and the Bureau of Land Management, with litigation and stakeholder engagement from municipal entities like the Los Angeles Department of Water and Power and advocacy groups associated with the Sierra Club and Natural Resources Defense Council. Climate policy drivers from the California Air Resources Board and federal initiatives under the Department of Energy have influenced retrofit and renewable integration strategies.

The intertie underpins regional markets by enabling transfers that stabilize prices for consumers in metropolitan areas like Los Angeles, San Francisco, and Sacramento while providing revenue streams for generators in the Columbia River Basin and Pacific Northwest utilities such as Bonneville Power Administration and Avista Corporation. It affects investment decisions by utilities including Pacific Gas and Electric Company, Southern California Edison, and municipal agencies like the Los Angeles Department of Water and Power, and shapes infrastructure funding and policy debates in forums such as the Federal Energy Regulatory Commission and state utility commissions. Broader economic effects touch industries reliant on reliable power in ports like Port of Los Angeles and Port of Oakland and are reflected in regional planning involving entities such as the Western Electricity Coordinating Council and California Independent System Operator.