What induces clean energy transitions? When transitional dynamics exhibit strong path dependence, a temporary shock to input composition can trigger permanent structural change. I examine whether such dynamics characterize the U.S. electricity sector's use of coal - the most climate-damaging...

On Aug. 8, 2005, President Bush signed the Energy Policy Act of 2005 (PL 109-58). This was the first major piece of energy legislation enacted since 1992 following five years of Congressional efforts to pass energy legislation. Among other things, the law contains tax incentives worth over $14...

This paper examines the effect of environmental policies on technological innovation in the specific case of renewable energy. The analysis is conducted using patent data on a panel of 25 countries over the period 1978-2003. It is found that public policy plays a significant role in determining...

The U.S. tax code provides a number of subsidies for low-carbon technologies. I discuss the difficulties of achieving key policy goals with subsidies as opposed to using taxes to raise the price of pollution-related activities. In particular, subsidies lower the cost of energy (on average)...

In a market subject to environmental regulation, a firmamp;apos;s strategic behavior affects the production and emissions decisions of all firms. If firms are regulated by a Pigouvian tax, changing emissions will not affect the marginal cost of polluting. However, under a tradable permits...

I generalize a benchmark model of directed technical change to allow innovations and factors of production (here energy resources) to be substitutes or complements. I show that a dominant sector is forever locked-in under substitutability but researchers' market incentives can drive a transition...