Mention hydropower and most people immediately think of enormous, New Deal-era projects like the Grand Cooley or Hoover Dams. These installations are iconic, but they are not the entire story. Hydropower currently generates 6.8%1 of the electricity used by the United States, but we are not yet using the full potential of our domestic hydro resources. By modernizing some existing large hydropower producers and equipping some other dams with electricity generation turbines, we could add more than 8 GW of new clean electric capacity to the grid.
Conventional hydropower is generated by dams and pump storage, and while the bulk of it is located in the Pacific Northwest and West, much of the nation benefits from hydropower.2 Existing installations collectively provide 101 GW3 of generation capacity. But there is much more power available without erecting any new dams.4 While we obviously cannot install turbines on all 50,000 of our nation’s unpowered dams,5 the Bureau of Reclamation (USBR) has identified 100 large dams that could generate significant amounts of hydropower.6 The U.S. could add a total of 8.225 GW of hydro-electric capacity by adding electricity generation capacity to those 100 dams and increasing the efficiency of turbines at existing facilities.7 That would be enough to power at least 6.2 million homes,10 more than in the states of Missouri, Louisiana, and Iowa combined.11
Assuming this new hydropower replaced coal, it would displace 31 million metric tons of annual greenhouse gas emissions.12 And hydropower produces no conventional pollutants, so it would remove as much nitrogen and sulfur oxides, mercury, and particulate matter as produced by about 13 average-size coal plants.13 These new hydro projects would also create as many as 48,000 additional jobs.14 Most of these new positions would be in the Southeast and the Midwest.15 Based on analysis of data compiled by the Idaho National Laboratory, the Midwest and South currently rely on only about 1 GW of hydropower capacity.16 This would be a substantial broadening of electricity resources for these regions.
The cost of hydro is competitive with other energy sources aside from natural gas at its current price. Levelized costs of hydro projects are expected to remain generally low, at $88.9 per MWh for the foreseeable future, compared to $110.9 per MWh for advanced coal (without CCS), $111.4 per MWh for advanced nuclear, and $66.1 per MWh for advanced combined cycle natural gas.17 Once built, hydropower needs no feed stock fuel unlike coal, natural gas, or nuclear, making it the cheapest source of baseload power to produce.18
Congress and the Administration should develop strategies to ensure facilities are modernized and use more efficient technologies, and certain unpowered dams should be electrified to provide power to underserved regions in the Midwest and South.