According to the Statistical Review of World Energy, human beings consumed the equivalent of 132,000 terawatt hours (TWh) of energy in the year 2008. One terawatt hour is equivalent to a billion kilowatt-hours (kWh). Numbers this big are difficult to relate to—but to put this into perspective, the average annual electricity consumption for a U.S. residential utility customer is just under 1,000 kWh per month (according to the U.S. Energy Information Administration), which adds up to about 4 TWh per year. The majority of electrical energy generation in the US comes from coal (45 percent), followed by natural gas (24 percent), and nuclear (20 percent). A mere 10 percent is generated by renewables, and of this wind generated power accounts for just over 2 percent, and solar 0.03 percent. It is estimated that worldwide energy consumption will increase by 30 percent from now until the year 2035. Our consumption of energy is insatiable, but unsustainably so in the way we produce it.
For all the hype about how renewable energy will save us from inevitable doom, its impact in the amount we produce annually, at less than 3 percent for wind and solar combined, is awfully underwhelming. If every building had a solar array on the roof, every yard a wind turbine, it still wouldn’t make much of a dent. And this is all the more frustrating when considering that, according to the Worldwatch Institute, the potential for annual renewable energy production worldwide is staggering; many times over what the world produces and uses annually—for all energy sources: