For the first time, hydropower accounts for less than 50% of U.S. renewable energy

Source: Nathanael Massey, E&E reporter • Posted: Tuesday, May 27, 2014

Solar and wind power may be leading the growth of renewables in the United States today, but it has long been an older source of energy — hydropower — that has dominated the renewable energy sector. Built for the most part decades before climate change entered the popular lexicon, hydroelectric has continued to supply the majority of the country’s clean, renewable energy, even as other power sources raced forward.

Until now, that is. In the first quarter of 2014, hydroelectric fell below 50 percent of total renewable electricity, outpaced by the collective output of solar, wind, biofuels, waste energy and geothermal, according to data from the International Energy Agency.Hydropower still held the largest minority share of the renewable energy pie, accounting for about 46.84 percent of the 135 million megawatt-hours of clean energy generated in the first three months of 2014. But that’s a significant decrease from the same period a year before, when it accounted for 50.66 percent of the total.

Output from all renewable resources fluctuates from year to year, depending on the weather, capacity increases, investment and many other factors. It is possible that, over the months ahead, hydropower could swing back up to claim more than half of renewable output.

But over a longer timeline, the growth trajectory of the different renewable resources indicates that hydropower will claim a smaller and smaller portion of total renewable energy output.

While geothermal energy, landfill gas and solar thermal energy have all made gains over the past decade, it is primarily two power sources — wind and solar photovoltaic — that have accounted for the sector’s rapid expansion.

Wind, which in 2004 generated 14 million MWh of electricity, accounted for well over 167 million MWh last year. Solar photovoltaic grew even faster — although its share of the overall total remains smaller — going from 6,000 MWh in 2004 to more than 8 million in 2013.

Hydropower’s output, by contrast, has been more or less flat over the same period. Most of the country’s hydropower came online in the first half of the 20th century, as demand for electricity grew and expanded in Southern and Western states. Dam building peaked in the 1960s, declining sharply thereafter due, in part, to environmental concerns.

And to be sure, hydropower’s shrinking share represents its relatively stable status in a growing sector, rather than a constriction of its output. Electrical generation from the sector as a whole accounted for about 13 percent of U.S. electrical generation in the first quarter of this year, up 3.29 percent from the same period last year, according to nonprofit research organization the SUN DAY Campaign.