The first article in this series made the case for removing the dams on the Snake River because of the importance we place on wild salmon, drawing on analysis from a recent report by ECONorthwest (ECONW). A second reason to remove the dams, beyond boosting the odds of salmon survival, is that they are no longer—or will soon no longer be—the cheapest option for generating the power that they produce.
Low-cost hydro electricity from the federal hydro system has provided a competitive advantage to the economy of the Pacific Northwest since the 1940s. But over time the dams, penstocks, turbines, and power lines aged and the costs of helping declining fish populations move through the system went up. In the last decade, a boom in solar and wind power has reset West Coast energy markets, undercutting not only coal-fired power but also aging hydro-electric projects.
The four lower Snake River Dams—Ice Harbor, Lower Monumental, Little Goose, and Lower Granite—have operated for half a century with a combined maximum capacity of over 3,000 megawatts. The dams are owned and operated by the US Army Corps of Engineers (the Corps). The Bonneville Power Administration (Bonneville) markets their output and delivers their electricity through its transmission system. The dams’ annual output is about 1,000 average megawatts, about one third of their peak capacity.
Figure 1 shows the maximum generating capacity of Snake River dams compared to all the other power generators in the region. The dams are considered “run of river,” which means they have relatively little storage capacity compared with other Northwest dams. Their output is highest in the spring as snow melts in the mountains and then electricity production falls in late summer and fall.