Wind project performance with age: Policy, technology, markets, and the maturing wind power industry

U.S. wind generation capacity has grown by a factor of nearly 50 times in the past 20 years; now nearly a third of wind capacity is 10 years old or older. This ageing of this fleet affects the productivity of existing investments and raises the stakes for replacing these assets through repowering. Focusing on the Texas wind power fleet to examine declining productivity over time, and how those changes factor into replacement and retirement decisions, we corroborate earlier decline findings but observe a slower rate of repowering than in other settings. We then explore repowering decisions and find evidence that technological change has favored relatively unproductive sites, in contrast to the previous literature on this topic. We explore the policy implications of our findings, in particular the desirability and feasibility of using policy tools to promote more repowering.