In January 2006, the Idaho National Laboratory (INL) issued a report that concluded that there are a large number of opportunities for increasing U.S. hydroelectric generation throughout the United States. These opportunities collectively represent a potential for approximately doubling U.S. hydroelectric generation (not including pumped storage), but more realistically offer the means to at least increase hydroelectric generation by more than 50 percent.

The 68-page report "Feasibility Assessment of the Water Energy Resources of the Untied States for New Low Power and Small Hydro Classes of Hydroelectric Plants" found that, with the exceptions of part of most of eight states, potential hydropower projects are abundant throughout the country.

For its study, the INL used a run-of-river model, which employs a penstock to direct water through a powerhouse and then back into streams without any impoundment of water. For the addition of powerhouses to existing dams and for adding capacity to existing hydropower operations, the INL considered an assortment of current turbine technologies.

The INL evaluated the likelihood of development based on land use and environmental sensitivities, prior development, site access, and load and transmission proximity, and only included those sites in its estimate that met all of the criteria. For new sites, only streams that demonstrated power greater than 10 akW and were within one mile of a road and transmission lines, a power plant or substation -- or were within a distance of population centers comparable to other power plants of the same power class in the area -- were included. Funding of potential projects, however, was not addressed in the report.

INL found that of the approximately 300,000 MWa of total, gross power potential of U.S. natural stream water energy resources, only about 10 percent has been developed. About 30 percent are located in zones where development is unlikely. The remaining 60 percent of over 170,000 MWa have not been developed and are not restricted from development based on information sources used in the assessment.

Of this potential, it was found that nearly 100,000 MWa of gross power potential could feasibly be developed. This feasible potential corresponds to nearly 130,000 potential low-power and small hydro projects. Estimation of the hydropower potential of these sites indicates 30,000 MWa of new power supply could feasibly be developed in the United States.

The West is home to nearly 20,000 MW of these undeveloped, prime hydropower opportunities. Moreover, the sum of feasibly developable hydropower in the Western states roughly equals the region's developed hydropower, in terms of potential average megawatts.

The potential sites evaluated in the West were for small damless hydropower operations of up to 30 MW and for low-power operations of less than 1 MW, which could account for 10,000 MW, in addition to adding powerhouses at existing dams and expanding capacity at existing hydroelectric plants, which could account for another 10,000 MW. Combined they could contribute toward the Western Governors' Association's (WGA) goal of developing 30,000 MW of clean energy in the West.

Of the 18 Western states represented by the WGA, Six western states - Alaska, Washington, California, Idaho, Oregon, and Montana - have the highest hydropower potentials. From the perspective of the density of hydropower potential (kWa/sq.mi.) that could feasibly be developed, Hawaii and Washington have the highest densities of feasibly developable resources.

With the exception of Washington, which already has the highest amounts of hydroelectric generation among the states by a wide margin, these six western states have sufficient hydropower potential to increase their generation by between 60 an 1600%. Alaska has sufficient hydropower potential to increase its hydroelectric generation by nearly a factor of 16. Hawaii, if it developed its potential projects, would also increase its hydroelectric generation by more than a factor of ten.

However, there are a large number of feasible potential projects to choose from, and they are located such that most states could benefit from a significant amount of additional renewable energy if they were developed. In fact, by comparing hydropower potential associated with feasible projects to the total annual average power of the existing hydroelectric plants in the state, it was found that 33 states could increase their hydropower generation by 100 percent or more and 41 states could realize increases of more than 50 percent.

In total, development of the 5,400 feasible small hydro projects alone would provide more than a 50 percent increase in U.S. hydroelectric generation.

The majority of the identified feasible hydropower potential could be harnessed without constructing new dams and by using existing techniques and technologies developed over the long and extensive history of installing small hydroelectric plants in the U.S. In fact, 84 percent of the identified hydropower potential could be developed using existing
technology.

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The complete 68-page study "Feasibility Assessment of the Water Energy
Resources of the United States for New Low Power and Small Hydro Classes of
Hydroelectric Plants, January 2006" can be found at:

http://hydropower.inl.gov/resourceassessment/pdfs/main_report_appendix_a_final.pdf

An article which examines the hydropower potential in western states, based
on this study, was published in the April 7, 2006 edition of "Energy
Prospects" newsletter. It can be found at:

http://www.energyprospects.com/cgi-bin/package_display.pl?packageID=1817