The precipitous fall in oil prices, continued geopolitical instability and the ongoing climate negotiations are witness to the dynamic nature of energy markets. In a time of so much uncertainty, understanding the implications of the shifting energy landscape for economic and environmental goals and for energy security is vital. The World Energy Outlook 2015 (WEO-2015) presents updated projections for the evolution of the global energy system to 2040, based on the latest data and market developments, as well as detailed insights on the prospects for fossil fuels, renewables, the power sector and energy efficiency and analysis on trends in CO2 emissions and fossil-fuel and renewable energy subsidies.