Our Untapped Water Power Potential

Hydroelectricity is the leading source of renewable energy in the U.S. Yet Washington continues to ignore it in favor of costlier and less-dependable solutions.

Hydroelectricity is the leading source of renewable energy in the United States, hydroelectric power plants produced 248 billion kilowatt-hours of electricity in 2008. In the same year, wind, geothermal and solar power plants produced 52 billion, 15 billion and 843 million kilowatt-hours of electricity, respectively. Despite this, the cost and environmental damage associated with hydroelectricity has prevented the construction of new dams. Fortunately, it is possible to massively expand the production of hydroelectric power without building dams.

The majority of existing dams and diversions in the United States do not generate electricity. According to the Army Corps of Engineers, only 2,516 of the nation’s roughly 83,000 dams generate electricity. Most of these dams were built for a number of other purposes, such as flood control or irrigation. When energy prices were low in the 1980’s and 90’s, there was no incentive to retrofit the dams to produce electricity.

According to the Department of Energy existing dams and diversions in the U.S. have over 25,000 megawatts of undeveloped capacity to generate hydroelectricity. While estimates vary by location and other factors, 1 megawatt is roughly enough electricity to power 650 U.S. houses. This would increase the installed capacity of hydroelectric installations in the United States by almost a third.

The official numbers underestimate the true potential hydropower of existing dams. The report focused on powerplants of greater than 1 megawatt capacity but projects under 1 megawatt can also contribute to the nation’s energy supply. Small hydroelectric powerplants can support the national electric grid and improve energy supplies in remote locations. By including small hydropower sites, the potential of existing dams and diversions would go far beyond the 25,000 megawatts identified by the Department of Energy.

The impact of 25,000 megawatts of additional hydropower on the U.S. energy supply would be impressive. Over 70 billion kilowatt-hours of electricity would be produced annually. This is just under 2% of total electricity consumption in the United States.

Retrofitting dams with turbines would also help facilitate the development of wind, solar and geothermal power. Since hydroelectricity is easily turned up or down to match demand, it is a good partner with other power plants. Wind and solar power are intermittent, and subject to rapid changes in productivity depending on the weather. The on-demand flexibility of hydroelectricity would be a good complement to that.

A widespread dam retrofit project would facilitate renewable energy development in other ways. Many of the nation’s dams with undeveloped hydroelectric potential are far from existing power lines and other infrastructure. Tying these new hydroelectric power plants into the national grid would improve access to other renewable resources. Throughout the western United States, existing dams are close to high-quality wind and geothermal resources that could be tapped.

The environmental benefits would be profound. 70 billion kilowatt hours of hydroelectricity would translate into 70 million tons of carbon dioxide emissions avoided if coal-fired electricity were displaced. This represents over 1% of total U.S. carbon dioxide emissions.

A plan to install hydroelectric turbines in existing dams would provide economic benefits. Employment would be created in a broad range of industries. Large amounts of work for plumbers, pipefitters, engineers, linemen, concrete workers, heavy equipment operators and other construction workers would be created. Many of these dams are in rural areas with high unemployment and many of these jobs would be concentrated in the construction sector, which has been devastated by the housing crash.

Hydroelectricity would likely displace natural gas as a source of power. This is because natural gas power plants are similar since they can also be easily turned up and down to match demand. There are a number of reasons why displacing natural gas is as a power source is desirable.

While natural gas remains an efficient fuel for space heating, water heating and cooking, the leading consumer of natural gas in the United States in 2008 is still the electric sector. Natural gas supplies are problematic. About 3/4ths of the world’s natural gas lies under the former Soviet Union, Venezuela and the Middle East. Natural gas exporters are currently looking into forming an OPEC-like cartel. Displacing natural gas from electricity generation would reduce dependency on imports and reducing overall demand for natural gas is also likely to help contain prices.

The total cost of retrofitting these dams with turbines would run around 50 billion dollars. Turbine retrofits would be more expensive than natural gas power plants on a per-kilowatt basis, but cheaper than nuclear power plants. In addition, unlike natural gas and nuclear power plants, the fuel for a hydroelectric power plant is free. Future rounds of economic stimulus spending would be well-spent on installing turbines in government-owned dams. Some or all of the cost of these projects could be recouped in electricity sales.

The federal government needs to simplify and expedite the process for installing turbines into existing dams. Symbiotics LLC began pursuing a license to install a 3.3 megawatt turbine in Chester Dam in 2001. The Federal Energy Regulatory Commission did not issue a license until 2008. Federal authorities need to streamline this process without omitting the public’s concerns. These projects can impact fisheries in much the same way that wind farms impact bird populations. However, most of the environmental damage from dams will occur whether or not the dams generate electricity.

Secondly, a carbon tax or a cap and trade regime will decisively improve the economics of these projects. Electricity generated by coal and natural gas will become more expensive, and hydroelectricity will become much more cost-competitive. When utility companies evaluate the long-term cost-benefit ratios of hydroelectric dam retrofits, they will no longer need to consider the possibility of sustained low prices for natural gas and coal that prevailed throughout the 1980s and 90s.

Finally, state, local and private-sector initiatives to obtain a share of electricity from green resources should include low-impact hydroelectric projects. The Low Impact Hydroelectric Institute (LIHI) certifies projects that meet rigorous standards for watershed protection and environmental stewardship. LIHI-certified projects should be given parity with wind, solar, biomass and geothermal power in renewable energy portfolios.

By taking these steps, the United States can unleash a new era of hydroelectric power. Now is the time for a hydroelectric renaissance in existing dams and diversions.