In the IEO2013 Reference case, which does not include prospective greenhouse gas reduction policies, coal remains the second largest energy source worldwide. World coal consumption rises at an average rate of 1.3 percent per year, from 147 quadrillion Btu in 2010 to 180 quadrillion Btu in 2020 and 220 quadrillion Btu in 2040 (Figure 70).