From the late 1800s, when the first hydropower turbines were installed on Columbia River tributaries, into the 1960s water power from dams in the Columbia River Basin provided most of the electricity in the Pacific Northwest. Then, as population increased and the regional economy grew, demand for electricity surpassed the output of the dams. Other types of power plants were built, steadily adding to the region’s electricity supply. Primarily these were thermal plants fueled by coal, nuclear fission and natural gas. These plants boil water to make steam; the pressurized steam drives power-generating turbines. The modern power supply also includes propeller-driven turbines that make electricity from wind.
Electricity in the Northwest still is dominated by hydropower, which accounts for about 51 percent of the supply. The amount of hydropower varies with water conditions. Most of the region’s hydropower is generated on the Columbia River and its tributaries, but there also are dams on other rivers, particularly those that empty into Puget Sound. In years when precipitation and runoff are normal, the region’s hydroelectric system can provide about 16,000 average megawatts of electricity (an average megawatt is one million watts supplied continuously for a period of one year). The amount can be as much as 20,000 in a wet year or as little as 12,000 in a dry year. About 20 percent of the region’s electricity comes from plants that burn coal, and about 21 percent comes from plants that burn natural gas. The region’s single operating nuclear plant, located in eastern Washington, provides 3.2 percent of the region’s power. In all, the region’s power supply totals about 32,000 megawatts.
The resource not shown in this map — in fact, the most important resource to the Council — is energy conservation. Consistent with the Northwest Power Act of 1980, the federal law that authorized the four Northwest states to create the Council, energy conservation gets planning preference over all other sources of electricity to meet future demand for power. At a cost that is less than the cost of building new generating plants, measures can be implemented to improve energy efficiency — insulation, double-paned windows, compact fluorescent light bulbs, low-wattage traffic lights and energy-efficient industrial motors, for example. Between 1983, when the Council completed its first Northwest Power Plan, and 2004 more than 2,900 megawatts of conservation have been achieved in the Northwest. Expressed as energy generation, that is more than enough power for two cities the size of Seattle.