The adoption of renewable energy technology has received significant government support. However, there is limited empirical evidence on the effectiveness of subsidies that are used to promote the adoption of such technologies. This paper exploits a natural experimental setting, in which a solar PV subsidy is assigned randomly within a group of households applying for the subsidy. Combining data gathered from 100,000 aerial images with detailed information on 15,000 households, we estimate the impact of subsidy provision on the adoption of solar PV, installed capacity, timing of the adoption, and, ultimately, electricity consumption. The results show that, within the group of households that applied for the subsidy, the provision of subsidy leads to a 14.4 percent increase in the probability of adopting solar PV, a 9.6 percent larger installation, and a 1-year faster adoption. However, examining the subsequent electricity consumption of the applicants, we report that the subsidy provision leads to a decrease in household electricity consumption of just 8.1 percent, as compared to the rejected applicant group, implying a cost of carbon of more than €2,202 per ton of CO2