Numbers Don't Lie: 71 Things You Need to Know About the World

by Vaclav Smil

Portable electronics don’t last long—on average, just two years—and so the world’s annual production of these devices embodies about 0.5 exajoules per year of use. Because passenger cars typically last for at least a decade, the world’s annual production embodies about 0.7 exajoules per year of use—which is only 40 percent more than portable electronic devices! I hasten to add that these are, necessarily, only highly approximate calculations—but even if these rough aggregates were to err in opposite directions (that is, if car-making actually embodies more energy than calculated, and electronic production needs less), the global totals would still be surprisingly similar, with the most likely difference no greater than twofold. And looking ahead, the two aggregates might get even closer: annual sales of both cars and mobile devices have been recently slowing, but the future looks less promising for internal combustion engines. Of course, operating energy costs of the two classes of these highly energy-intensive devices are vastly different. A compact American passenger car consumes about 500 gigajoules of gasoline during a decade of its service, five times its embodied energy cost. A smartphone consumes just 4 kilowatt-hours of electricity annually and less than 30 megajoules during its two years of service—or just 3 percent of its embodied energy cost if the electricity comes from a wind turbine or from a photovoltaic cell. That fraction rises to about 8 percent if the en...