The Great Wind Energy Forest

Those of us who work in energy communications for a living are always looking for new equivalents–new ways to give an average reader some sense of the size and scale of what we are talking about.

Mark Twain was fond of quoting the saying, "There are three kinds of lies: lies, damned lies, and statistics." Another old saw puts the same skepticism this way: "Figures can’t lie, but liars can figure."

I have a slightly different take–I think of statistics as something like a telescope. A telescope doesn’t distort the visual information it conveys to the eye, but the scale of that information changes dramatically depending on which end you look into. And of course, that means that you have to be willing to invest at least a modest amount of time in learning about the subject in question so that you know which end of the telescope is which.

A good example is the amount of electricity generated by the current U.S. wind turbine fleet. After a decade of explosive growth, wind power now generates … 3% of America’s electricity. Sounds pretty puny, doesn’t it? And in fact, anti-wind farm groups like to point to that end of the telescope, perhaps adding emphasis by describing it as a "tiny fraction."

Our business at AWEA, of course, is to help people look through the telescope’s other end:

– To generate as much electricity from coal as wind energy will produce this year would take a coal train 6,000 miles long–more than enough to stretch from Los Angeles to London.

– To generate that same amount of electricity with oil would take a million barrels of oil, every two days.

Suddenly that "tiny fraction" seems quite a bit larger–which is the point: the truth is that America uses a gigantic amount of energy, and so even a small portion is actually a lot.

Which brings me to the title of this article: "The Great Wind Forest." What does it mean? It’s an invitation to consider the U.S. wind turbine fleet in terms of the amount of carbon dioxide (CO2), the leading greenhouse gas, it displaces, and to compare that with how large a forest it would take to absorb the same amount of carbon dioxide from the atmosphere. The answer turns out to be an eye-popping statistic, in my opinion.

Based on the total wind farm capacity installed as of the end of last year, U.S. wind turbines are expected to generate about 114 billion kilowatt-hours of electricity this year and to prevent, by displacing fossil-fuel generation, the emission of 66 million metric tons of CO2.

How much CO2 per year can a forest absorb? The number appears to vary, from about 0.3 tons per acre for Maine’s forests to as much as 1 ton per acre for fast-growing Southern pines.

Taking the latter estimate, the U.S. wind turbine fleet is equal to a forest of 66 million acres in terms of its effect on CO2 in the atmosphere. Since there are 640 acres in a square mile, that would be a forest of 103,000 square miles, which works out to be the size of New York and Pennsylvania combined.

Using the Maine forest absorption rate more than triples the area, to 220 million acres and 343,000 square miles. To New York and Pennsylvania, you’d have to add Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, New Jersey, Maryland, Delaware, West Virginia, Virginia, North Carolina, and South Carolina.

Caveat: This is not intended to denigrate forests or their multitude of valuable attributes (wildlife habitat, lumber, recreation, solitude, etc.) or to suggest that we substitute wind turbines for them. It’s simply a way of giving an idea of the scale of one of the primary benefits of the wind turbines already installed in the U.S. today. I think you’ll agree: it’s pretty impressive.

By Tom Gray,