Economists Without Calculators
Be wary of op-eds in the New York Times that tout an “environmental revolution.”

Wind turbines in Lincolnshire


Robert Bryce

Last week, just before the opening of the U.N.’s Earth Summit meeting in Rio de Janeiro, the New York Times ran an op-ed that decried the rapid rise in carbon dioxide emissions during the two decades since a similar meeting was held in Rio.

The authors of the article — Christian Azar, a professor at Sweden’s Chalmers University of Technology, and two economists from the Environmental Defense Fund, Thomas Sterner and Gernot Wagner — claimed that the world needs to “kick its addiction to fossil fuels” and that renewable energy provides the road to salvation because “the seeds of an environmental revolution are being sown.”

The authors’ solution was a familiar one: a carbon tax and/or a cap on carbon dioxide emissions. Never mind that the failure of the meeting at Rio shows, yet again, that a global carbon tax or emissions cap stands absolutely no chance of being implemented. Further, let’s ignore the claim that we have an “addiction” to hydrocarbons, which remain the cheapest, most abundant, most reliable source of energy for billions of people all over the world.

Instead, let’s consider the issue that Azar, Sterner, and Wagner — along with nearly every other proponent of “green” energy — refuse to consider: scale. A simple bit of math shows that even with the rapid expansion that solar-energy and wind-energy capacity have had in the past few years, those two sources cannot even meet incremental global demand for electricity, much less make a dent in the world’s overall demand for hydrocarbons.

Between 1985 and 2011, global electricity generation increased by about 450 terawatt-hours per year. That’s the equivalent of adding about one Brazil (which used 485 terawatt-hours of electricity in 2010) to the electricity sector every year. And the International Energy Agency expects global electricity use to continue growing by about one Brazil per year through 2035.

How much solar capacity would be needed to produce 450 terawatt-hours? Well, Germany has more installed solar-energy capacity than any other country, with some 25,000 megawatts of installed photovoltaic panels. In 2011, those panels produced 18 terawatt-hours of electricity. Thus, just to keep pace with the growth in global electricity demand, the world would have to install about 25 times as much photovoltaic capacity as Germany’s total installed base, and it would have to do so again every year.

The scale problem is equally obvious when it comes to wind.

At the end of 2011, the U.S. had 47,000 megawatts of installed wind-energy capacity. (Only China, with 62,000 megawatts, had more.) In 2011, all the wind turbines in the U.S. together produced about 120 terawatt-hours of electricity. Thus, just to keep pace with the growth in global electricity demand by using wind energy, we would have to install about 3.75 times the total current installed wind capacity in the U.S. every year. That means that global wind-energy capacity would have to increase by about 176,000 megawatts each and every year.

That would be an enormous challenge, given that between 2010 and 2011, global wind-energy capacity increased by just 41,000 megawatts. That’s a record increase, and one that advocates of renewable energy are quick to laud. But those same advocates refuse to acknowledge the energy sprawl inherent in wind energy, nor will they admit the growing backlash against the wind industry.

Let’s consider the extent of the energy sprawl if wind energy were to supply that 450 terawatt-hours per year of incremental electricity demand.

The power density of wind energy is roughly two watts per square meter, or about five megawatts per square mile. That means that by the end of 2011, the U.S. had covered a land area of about 9,400 square miles, just slightly smaller than the state of Maryland, with wind turbines. Therefore, to keep up with the growth in global electricity demand by using wind energy alone, the global wind industry will need to cover a land area of some 35,000 square miles — about the size of Indiana — with wind turbines. And it will have to do so every year from now through 2035.

That metric’s still hard to grasp, so let me put it another way: In order to merely keep up with the growth of global electricity use, the wind industry would have to cover 96 square miles every day with wind turbines. That’s an area about the size of four Manhattans.

Glib economists might suggest that such a feat could be achieved, but that ignores another key question: Where will we put all those turbines?


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