Installed wind electric generating capacity in the United States surpassed conventional hydroelectric generating capacity, long the nation’s largest source of renewable electricity, after 8,727 megawatts (MW) of new wind capacity came online in 2016. However, given the hydro fleet’s higher average capacity factors and the above-normal precipitation on the West Coast so far this year, hydro generation will likely once again exceed wind generation in 2017.
Wind and hydro generation both follow strong seasonal patterns. Hydro generation typically reaches its seasonal peak in the spring and early summer, especially in the Pacific Northwest and California where about half of U.S. hydropower is produced. Across most of the country, wind generation typically peaks in the spring with a smaller peak in late fall and early winter. The Pacific Northwest and California have a slightly different seasonal pattern for wind resources, with generally only one peak in the early summer.
In the Southwest Power Pool (SPP) electric system, which extends from northern Texas to North Dakota and Montana, wind power recently supplied more than half of the system’s generation mix for a brief period, reaching 52.1% (11,419 MW) in the early hours of February 12, 2017—a first for any of the seven U.S. regional transmission organization (RTO) electric systems that together serve two-thirds of the country’s electricity consumption.
The Electric Reliability Council of Texas (ERCOT) system which covers most of Texas continues to set records for the highest level of wind generation on any U.S. electric system. ERCOT’s most recent record of 16,022 MW occurred on the morning of December 25, 2016, and accounted for slightly more than 47% of the generation mix at the time.