LBNL reported the following comparative performance numbers for wind turbines. The comparison is between 1998-99 and 2015:
- Average capacity of WTG has increased by 180%
- Average hub height has increased by 47%
- Average rotor diameter has increased by 113%
As a result of these, the capacity factor of WTGs has increased from 26% to 41%.
In 2015, the average prices of wind projects had fallen to $1,690/kW (which is 20% to 40% below 2008 prices)
With these efficiencies and cost reductions, PPA for wind projects in US are averaging about $0.02/kWh in 2015.