This study assesses the risk of energy accidents using an original historical dataset over the period 18742014, and it evaluates that risk across 11 energy systems: biofuels, biomass, coal, geothermal, hydroelectricity, hydrogen, natural gas, nuclear power, oil, solar energy, and wind energy. Our study shows how these energy systems collectively involved almost 1,100 accidents resulting in more than 210,000 human fatalities and almost $350 billion in property damages. Across the entire sample, the mean amount of property damage was $319 million and 196 fatalities per accident, though when reflected as a median the numbers substantially improve to $3 million in damages per accident and 0 fatalities. We found that wind energy is the most frequent to incur an accident within our sample, accounting for almost one third of accidents. Accidents at hydroelectric dams were the most fatal, accounting for 85 percent of fatalities. Nuclear power accidents are by far the most expensive, accounting for 70 percent of damages. We then utilize this data to test six hypotheses, drawn from the energy studies literature, related to energy systems, energy policy and regulation, and technological learning. (C) 2015 Elsevier Ltd. All rights reserved.