On the last day of August 1964, Congress approved the Pacific Northwest Consumer Power Preference Act (Public Law 88-552), which authorized the sale of federal Columbia River hydropower to the Southwest, particularly to California, over the Pacific Northwest/Pacific Southwest Intertie, but only power that was surplus to needs in the Northwest.

The Preference Act could be said to have its roots in the public preference clause of the 1937 Bonneville Project Act, which states in Section 4(a) that the federal Columbia River dams “shall be operated for the benefit of the general public” and that in selling power from the federal dams the Bonneville Power Administration “shall at all times … give preference and priority to public bodies and cooperatives” (See Norwood, Columbia River Power for the People, Page 69).

The preference act was one of several federal laws approved through the summer and fall of 1964 that made the year one of the most important in the history of the Pacific Northwest electric energy system.

The Columbia River Treaty, ratified on September 16, ensured that storage dams that would be built in British Columbia would be operated in a way that would maximize hydropower generation downstream in the United States. In response, additional generating units were planned and later built at Grand Coulee and Bonneville dams. Canada and the United States would share equally in this additional generation, called the downstream benefit, but British Columbia didn’t need the extra power and so was interested in selling it in the United States. But high-voltage transmission lines were not available to carry the power to willing buyers in southern California and the Desert Southwest. The Intertie, approved by Congress on June 24, provided the electron superhighway that made power exchanges possible between the Northwest and Southwest, including the sale of Canada’s share of the so-called downstream benefit under the Columbia River Treaty.

But customers of the Bonneville Power Administration did not like the idea of the Intertie if it might be used to sell firm Columbia River hydropower to California utilities, which those utilities wanted. So the Preference Act ensured that Bonneville’s customers would continue to have have preference to Bonneville’s electricity from the Federal Columbia River Power system and that Bonneville would only sell surplus energy to utilities in California and the Southwest.

The Preference Act states, in Section 2, that … “the sale, delivery, and exchange of electric energy generated at, and peaking capacity of, Federal hydroelectric plants in the Pacific Northwest for use outside the Pacific Northwest shall be limited to surplus energy and surplus peaking capacity.”

To ensure the treaty would have its intended effect, 17 Northwest utilities that generate power and would be able to take advantage of the Intertie signed the Pacific Northwest Coordination Agreement on September 15. Historian Jim Kershner provides an excellent history of coordination among power producers in the Northwest and Canada in his HistoryLink essay on the Northwest Power Pool.