This paper analyzes the impacts of consumer subsidies in the global market for solar panels. Consumer subsidies can have at least two effects. First, subsidies shift out demand and increase equilibrium quantities, holding production costs fixed. Second, subsidies may encourage firms to innovate to reduce their costs over time. I quantify these impacts by estimating a dynamic structural model of competition among solar panel manufacturers. The model produces two key insights. First, ignoring long-run supply responses can generate biased estimates of the effects of government policy. Without accounting for induced innovation, subsidies increased global solar adoption 49 percent over the period 2010-2015, leading to over $15 billion in external social benefits. Accounting for induced innovation increases the external benefits by at least 22 percent. Second, decentralized government intervention in a global market is inefficient. A subsidy in one country increases long-run solar adoption elsewhere because it increases investment in innovation by international firms. This spillover underscores the need for international coordination to address climate change.