HOLTWOOD, Pa. - The century-old dam on the Susquehanna River doesn't look like an energy source of the future.
Weeds sprout out of cracks in the weathered Holtwood Hydroelectric Dam, 12 miles upriver from Maryland. Inside the generating building, antique brass volt meters look like something from Dr. Frankenstein's lab. Water snakes slither across the floor.
Despite the decrepit appearance, a Pennsylvania power company is planning to spend $350 million to build new water-powered turbines next to the dam. The first new hydroelectric power plant in the East in 20 years, it would double the dam's electrical output, providing another 100,000 homes in the region with pollution-free electricity, according to the company.
At a time when utilities are looking to generate more power without global-warming pollution, some point to the PPL Corp.'s Holtwood project as a good example of going back to the future.
"Hydropower has been nearly forgotten, but it's a great source of electricity because it's completely emission-free and combustion-free generation," said Douglas Hall, manager of the water energy program at the U.S. Department of Energy's Idaho National Laboratory.
Increasing the efficiency of old plants can create more juice to meet rising demand, Hall and others say. Across the country, power companies are upgrading generators in 23 dams in Idaho, Kentucky and California, among other places.
Hydroelectric dams were the original source of electricity for many of America's cities a century ago. As late as the 1940s, 40 percent of the electricity in the U.S. was generated by water pushing wheels and spinning turbines. But the technology was neglected for decades after World War II as coal-burning plants took over the dominant role in generating America's electricity.
America today gets 7 percent of its electricity from hydroelectric power, and this could rise to perhaps 11 percent by simply adding more and better generators to existing dams, Hall estimated. That would mean more clean energy without blocking additional rivers or flooding more valleys - major environmental drawbacks that halted most major construction of dams in the U.S. by the 1950s.
About 79,000 dams are scattered across the U.S., many dating to grain mills of the 19th century. Only 2,400 of these dams have hydroelectric generators built into them. Adding more turbines to the existing dams could add as much as 37,000 megawatts of power, Hall said. That's enough electricity to light up 27 million homes.
