U.S. wind energy generation has outpaced the growth in new wind power capacity, thanks to innovative technological advancements, according to the American Wind Energy Association (AWEA). The group says that over the past five years, U.S. wind energy capacity grew from 25 GW to over 61 GW, a 140% growth rate, yet electricity generated from these wind turbines grew at a rate of 200%, exceeding capacity growth and making wind energy cheaper than ever.
AWEA says the increasing performance and production of wind turbines is the result of technological innovation and operational improvements, which have effectively driven down the costs and allowed development to occur in lower wind speed regions.
Advancements undertaken by manufacturers include designing taller towers and turbines with longer and lighter blades, allowing rotor diameters to exceed 100 meters. As AWEA explains, the power of the wind is directly proportional to the swept area of the blades, so an increase in rotor diameter has spurred development in low and medium wind speed areas and has added to the efficiency of existing sites.
"Wind turbine and component manufacturers have been diligently working over the last few years to develop longer, lighter advanced technology blades that allow the systems to produce more energy at lower costs," comments Steve Lockard, president and CEO of TPI Composites. "Continued reduction in levelized cost of energy (LCOE) is key to making wind even more competitive with conventional electricity sources."
AWEA adds that tower heights have also grown steadily in the last five years, allowing developers to access higher, steadier wind resources. A decade ago, the average wind turbine was installed on a 65-meter tower. Today, the group says, the average wind turbine sits atop an 80-meter tower, but 85- and 100-meter towers are increasingly utilized.
The combination of taller towers and larger rotor diameters has been vital to bringing the cost of wind energy down, allowing developers to build projects in a cost-effective manner in locations like the Great Lakes. AWEA says states like Indiana, Ohio and Michigan have experienced rapid growth and a decrease in the price of wind power once tower heights reached 80 meters.
Operational improvements have also contributed to the increased production. AWEA says more informed operations and maintenance strategies have led to the highest performance levels ever seen in the U.S. wind industry. Citing an assessment by the Sandia National Laboratory, AWEA says wind turbine availability, utilization and capacity factors have all improved over the past three years. In all, the group says U.S. Department of Energy data shows capacity factors have risen across the fleet, and at certain projects in wind-rich states, capacity factors have exceeded 50%.