Renewables forecast: rainy with patchy sunshine

A few headlines last week celebrated the news that in the U.S. renewable energy production now surpasses nuclear energy production. The increase, however, is hardly coming from the solar panels adorning your roof.

Conventional hydroelectric power still makes up the majority of renewable energy, as it has for decades. And, according to the National Hydropower Association, it's quietly rising. Compared to the same period last year, electricity from hydropower is up almost 30 percent. The energy share from biofuels increased last year too, continuing a 15-year trend, and -- when totaled with wood and municipal waste energy production -- actually exceed hydropower.

A high water year, thanks to record snowpack melts, is behind some of the hydropower increase. But plants are also finding ways to increase production: souping up operations with modern, better-working turbines and generators. An upgrade to the 93 year-old Cheoah Dam in Robbinsville, North Carolina will result in nearly 30 percent more power output, without altering the dam or using more water. That’s quite a jump. This is one of half dozen upgrade projects the Department of Energy is helping support through Recovery Act funds. Together, the projects will boost electric generation by about 187 GWh per year. And they'll do it pretty cheaply, at less than 4 cents per kWh.

Nor are dams the only route to hydro-electric power. "Small hydro" projects, fit into existing tunnels, canals or pipes, can generate without the need for new dams and reservoirs. In 2007 the San Diego County Water Authority completed an upgrade at a facility near Mira Mesa, California that generates 4.5 MW through a conduit.

Yet hydropower, although considered renewable, is hardly benign. It's the dams that are the real problem. Beyond the hefty construction expenses, they wreak havoc on the environment -- flooding land upstream, reducing flow down stream, and making the river much less productive. Much of the blame for the drastic declines in Western fish populations in the past few decades rests at the spillways of the big grand dams. (This fall, to restore the river ecosystem, two dams on the Elwha river in Washington state began to be dismantled.)

Though newer dams are built with fish in mind, some are inevitably lost. And reduced river flow makes it hard for fish to migrate, increases river temperature and reduces the nutrients that feed fish, plants and insects.

While the days of big grand dams construction are probably mostly behind us, they might not be over. Alaska especially holds huge development potential. A new major dam and power plant is proposed for the upper Susitna River about halfway between Fairbanks and Wasilla. The dam, if constructed, would produce up to 600 megawatts and would reduce the region's heavy dependence on natural gas.)

While some citizens in Alaska are already organizing in opposition to the proposed dams, in Washington D.C. interest in hydroelectric hasn't slowed. The Hydropower Improvement Act of 2011, currently with the House subcommittee on Water and Power, would substantially increase hydro-borne capacity in the U.S. According to the National Hydropower Association, the U.S. could boost production by at 60,000 megawatts, enough to power 6,000 homes for a year, by 2025, if policies (and the political climate) were favorable. And the 2012 Congressional budget sets aside $59 million for hydropower research and development -- more or less on par with the awards given to biomass and solar research in recent years.

While hydropower and biofuels may currently rule the renewable roost, solar energy is making a wildcard bid -- at least in terms of its speed of growth. Solar thermal and photovoltaic power generation makes up only a small fraction of renewable energy, about 1 percent, compared with hydroelectric's 37, but it’s rising quickly. Compared to the same period last year, power from solar is up almost 50 percent. Still, for the foreseeable future, the bulk of our renewable energy will resemble a Pacific Northwest weather forecast mostly rain, with patchy sunshine.

Danielle Venton is an intern at High Country News.

Image of hydroelectric facility courtesy of Flickr user B Rosen.