The DoE's latest wind technologies market report, compiled by the Lawrence Berkeley National Laboratory, found an average capacity factor in 2018 of 42% for projects built since 2014.
By comparison, the wind farms that came online from 2004 to 2011 achieved an average of capacity factor of 31%, while those completed between 2008-2001 returned 24%.
The efficiency of the recently built projects has now pushed the US's total wind fleet's capacity factor to over 35% for the first time.
The average rotor diameter of US turbines has grown 135% in the past 20 years to 113 metres. Average hub heights have climbed by 54% in the same period to 86 metres.
Permit applications to the Federal Aviation Administration show taller and higher-rated turbines are on the way.
They include GE's 5.3MW Cypress turbine, with a rotor diameter of 158 metres and a hub height of over 160 metres.