Wind power is poised to surpass hydroelectricity as the largest renewable energy generation source, the Energy Information Administration said on Jan. 24.
EIA notes that hydroelectric power has historically provided the largest share of renewable electricity generation in the United States. But based on forecasts in its latest Short-Term Energy Outlook, EIA expects wind power to surpass hydroelectricity in the near future.
Different factors lead to questions about the forecast level of electricity generation from each energy source, the agency noted in its “Today in Energy” report.
“Because few new hydro plants are expected to come online in the next two years, hydroelectric generation in 2018 and 2019 will largely depend on precipitation and water runoff,” EIA said. “Although changes in weather patterns also affect wind generation, the forecast for wind power output is more dependent on the capacity and timing of new wind turbines coming online.”
Hydro and wind generation follow seasonal patterns. Hydro generation is typically highest in the spring when precipitation and melting snowpack increase water runoff, the report noted. Wind generation is typically highest in the spring and fall, “reflecting the capacity-weighted mix of seasonal patterns in wind across the country.”
EIA said that hydro often has slightly higher annual capacity factors, or utilization rates, averaging 38% in 2016 compared with wind’s 35%.
EIA’s hydroelectric generation forecasts over the next two years are mostly based on projections of water runoff. After a relatively wet year in 2017 — when hydro provided 7.4% of total utility-scale generation — hydro generation is expected to be slightly lower at 6.5% of total utility-scale generation in 2018 and 6.6% in 2019.
EIA said it expects significant levels of new wind capacity to come online in 2018 and 2019. EIA’s most recent Preliminary Monthly Electric Generator Inventory survey shows wind capacity increasing by 8.3 gigawatts in 2018 and 8.0 GW in 2019. “If these new generating units come online as scheduled, they would add 9% to U.S. utility-scale wind capacity by the end of 2018 and another 8% by the end of 2019,” the report noted.
The agency said that because much of the new electric capacity comes online in the final months of each year, these capacity additions affect the subsequent year’s electricity generation values.
EIA expects wind to provide 6.4% and 6.9% of total utility-scale electricity generation in the U.S. in 2018 and 2019, respectively, which is up from 6.3% in 2017.
“If the forecast levels of both wind and hydro generation are met in 2019, it would be the first time that wind generation surpasses hydropower as the leading source of renewable electricity generation,” EIA said in the short-term energy outlook.