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In 2019, annual wind generation in the US. exceeded conventional hydroelectric generation for the first time, according to the US Energy Information Administration’s Electric Power Monthly. This means wind is now the top renewable source of electricity generation in the country.

Annual wind generation totalled 300 million MWh in 2019, exceeding conventional hydroelectric generation by 26 million MWh. Wind generation has increased steadily during the past decade, in part, the EIA says, because the production tax credit (PTC), which drove wind capacity additions, was extended.

Annual conventional hydroelectric generation has fluctuated between 250 million MWh and 320 million MWh in the past decade, reflecting a stable capacity base and variable annual precipitation. Hydroelectric generation is typically greatest in the spring when precipitation and melting snowpack increase water runoff. Although weather patterns also affect wind generation in different regions (with the greatest generation in the spring and fall), capacity growth has been the predominant driver of annual changes in wind generation, EIA reports.

Wind capacity additions tend to come online during the fourth quarter of the year, most likely because of tax benefits. Wind capacity additions totalled 10GW in 2019 (3.8GW installed in the fourth quarter), making 2019 the second-largest year for wind capacity additions in the U.S., second only to 2012.

Total installed wind capacity surpassed total installed conventional hydroelectric capacity in 2016. And as of the end of 2019, the US had 103GW of wind capacity, three-fourths of which (77%) was installed in the past decade. The US has 80GW of hydroelectric capacity, most of which has been operating for several decades. However, only 2GW of hydroelectric capacity has been added in the past decade, and some of those additions involved converting previously nonpowered dams.

Pumped storage in the U.S. adds 22,878MW (nearly 23GW) of capacity to the generation fleet. This brings the total installed US hydro capacity of 103GW, in line with wind.

Another important point is that the average annual capacity factors for the conventional hydroelectric fleet between 2009 and 2019 ranged from 35% to 43%. The average annual capacity factors for the US wind fleet were 28% to 35%. Capacity factors are the ratio of the electrical energy produced by a generating unit for a specified period of time to the electrical energy that could have been produced at continuous full power operation during the same period.

Note: The EIA does not include pumped storage or marine energy in its statistics around conventional hydropower. Potentially marine energy is included in the “other energy sources” category. Pumped storage is included in an energy storage category.

This story first appeared in a slightly different format on our sister-site,
Renewable Energy World.