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Impact of Policy Uncertainty on Renewable Energy Investment: Wind Power and PTC

28 Pages Posted: 18 Jan 2008 Last revised: 22 Mar 2015

Merrill Jones Barradale

University of Colorado at Boulder

Date Written: December 30, 2008


It is generally understood that the pattern of repeated expiration and short-term renewal of the federal production tax credit (PTC) causes a boom-bust cycle in wind power plant investment in the U.S. This on-off pattern is detrimental to the wind industry, since ramp-up and ramp-down costs are high, and players are deterred from making long-term investments. It is widely assumed that the severe downturn in investment during "off" years implies that wind power is unviable without the PTC. This assumption turns out to be unsubstantiated: this paper demonstrates that it is not the absence of the PTC that causes the investment downturn during "off" years, but rather the uncertainty over its return. Specifically, it is the dynamic of power purchase agreement (PPA) negotiations in the face of PTC renewal uncertainty that drives investment volatility. With contract negotiations prevalent in the renewable energy industry, this finding suggests that reducing regulatory uncertainty is a crucial component of effective renewable energy policy. The PTC as currently structured is not the only means, existing or potential, for encouraging wind power investment. Using data from a survey of energy professionals, various alternative policy incentives are considered and compared in terms of their perceived reliability for supporting long-term investment.

Suggested Citation

Barradale, Merrill Jones, Impact of Policy Uncertainty on Renewable Energy Investment: Wind Power and PTC (December 30, 2008). USAEE Working Paper No. 08-003. Available at SSRN: or

Merrill Jones Barradale (Contact Author)

University of Colorado at Boulder ( email )

1070 Edinboro Drive
Boulder, CO 80309
United States

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