Imagine what our economy would be like if almost half of our electricity came from renewable energy resources. No fuel price shocks, no foreign control, no worries about climate change—just clean, abundant, affordable electricity.

Before World War II, Americans actually lived that way, thanks to hydropower. The massive public works projects undertaken during the Great Depression built a fleet of huge facilities on some of the country’s biggest waterways. Job creation, electrification and inexpensive power modernized the rural South and helped to industrialize the West.

Then, the story goes, after the war ended and the atomic age began, hydropower growth slowed to a trickle. A myth that hydropower couldn’t expand any further gained currency. Well, get ready for some myth-busting.

Hydropower is the largest renewable resource in the U.S., providing about 8 percent of the nation’s electricity. Analysts say that capacity can double in 30 years, rivaling the growth predicted for the nuclear power industry and at a fraction of the cost. The Federal Energy Regulatory Commission is reviewing more than 30,000 megawatts’ worth of new projects, equal to a third of all existing hydropower capacity and big enough to power the New York metropolitan area.

Surprised? Many people are, because they still think of hydropower only on a scale of the giant Hoover Dam. The fact is, new technologies are creating ways to generate electricity in all kinds of waterways. For example, turbines that rotate slowly like underwater windmills can sit in rivers, aqueducts or other locations where water flows freely. Other units in oceans or tidal waters generate electricity as they bob up and down.

Even existing dams hold promise for energy production. Only about 3 percent of the country’s 80,000 dams generate electricity. Power-generating turbines could be added to many of these structures. The hydropower industry is encouraging the federal government, which owns many of these nonpowered dams, to begin assessing the potential.

Beyond that, engineers are finding ways to generate more electricity at existing hydroelectric dams by installing more efficient turbines and other technologies. The Grant County (Washington State) Public Utility District is almost halfway through a project to replace 10 turbines at its Wanapum Dam that will increase the facility’s capacity by more than 10 percent. The new turbines, developed through a public-private partnership, also offer a more “fish friendly” design.

Projects such as this one that maximize efficiency and reduce environmental impact are starting to attract support from environmentalists, who appreciate hydropower’s ability to provide reliable, affordable energy resources without greenhouse gas emissions.

The U.S. hydropower industry is pleased to see the Obama administration take a closer look, and we’re urging officials to invest in federal research and development that can propel new water power technologies to market. As the administration examines public works projects that can jump-start the economy, it should consider hydropower initiatives, just as its predecessors turned to hydro development during tough economic times 75 years ago.

The industry is also asking Congress to ensure that such development receives the same tax incentives given to other renewables. Hydropower should be part of state and federal policies, too. From renewable portfolio standards to comprehensive energy and climate strategies, hydropower offers a proved resource.

Note: This article was originally printed with the title, "Time to Think Hydro".