Investment opportunities in electric power generation have changed dramatically since electricity industry restructuring first began. In contrast to regulated utilities adding capacity in line with central planning and regulation, power plant investment is now more often made by independent companies who market power across multiple utility jurisdictions. Because the regulatory approval process is long and outcomes uncertain, developers often plan multiple options for a given development budget. As more information is revealed about the future prospects at different sites, options are abandoned sequentially until only projects that will be completed remain. In this paper we evaluate the decision to build new generation facilities in a changing and uncertain regulatory environment. We estimate hazard rates for new power plant projects using a database of generation projects in North America and examine in greater detail the development patterns in California and Texas, two states with very different regulatory regimes. We find that regulatory uncertainty significantly affects the pattern of development in the electric power generation industry. (c) 2006 Elsevier Ltd. All rights reserved.