Hydro power in the US contributes between 8-12% of total electrical generation. In the Pacific Northwest, 70% of electricity is generated by hydro power. Of the 75,187 existing significant dams in the US, less than 3% are used for hydro power. Total US hydroelectric capacity is 103.8GW (including pumped storage).
River basin analyses have shown there is nearly 70,000MW of potential hydro power development in the US. This only
takes into account engineering and economic factors. When screening for environmental, legal and institutional factors at potential sites there is almost 30,000MW.
Of this, 17,052MW is available at dams or impoundments without current hydroelectric capacity; an additional 4326MW of new generation is available at sites with hydroelectric facilities which have not been developed to their full potential; and only 8500MW of the potential would require new dams.