According to the International Energy Agency, global primary energy production in 2012 totaled 13,400 Mtoe . Oil accounted for 31.4% of the total, coal and peat accounted for 29%, natural gas for 21.3%, and nuclear for 4.8%. Only 13.5% of primary energy production came from sources that are or can be renewable: hydropower, biofuels, waste, geothermal, solar, and wind. As discussed in Chapter 2, society depends heavily on fossil fuels because they are convenient and “cheap,” from a market perspective. However, the broader lens of sustainability requires that we reexamine this assumption.