Robert Bryce: Dreaming the Impossible Green Dream - WSJ

Robert Bryce: Dreaming the Impossible Green Dream - WSJ

Mr. McKibben is among the world's most famous environmentalists. He's written or edited 15 books and been awarded honorary degrees from 18 colleges and universities. He is also the founder of 350.org, whose goal is to reduce atmospheric carbon-dioxide levels to 350 parts per million from the current level of about 400 parts per million. To achieve that goal, he's written that "we need to cut our fossil fuel use by a factor of twenty over the next few decades."

But what are the actual implications of cutting fossil fuels 20-fold? Let's "do the math," as Mr. McKibben is fond of saying.

Global hydrocarbon consumption is now about 218 million barrels of oil equivalent energy a day, according to the BP Statistical Review of World Energy, which includes 83 million barrels of oil as well as about 75 million barrels of oil equivalent from coal and about 60 million barrels of oil equivalent from natural gas. Reducing that by a factor of 20 would cut global hydrocarbon use to the energy equivalent of 11 million barrels of oil a day, roughly the amount of energy now consumed by India, where 400 million people lack access to electricity.

In 2012, the average resident of planet Earth consumed about 1.3 gallons of oil-equivalent energy a day from hydrocarbons. If Mr. McKibben's plan were enacted—and we shared those available hydrocarbons equally—-each of us would be allotted about eight fluid ounces of oil-equivalent energy from hydrocarbons a day. Today, the average resident of Bangladesh uses about half a liter of oil equivalent—slightly less than 17 ounces—a day. Under Mr. McKibben's prescription, the average Bangladeshi would be required to cut his hydrocarbon use by about half.

Like many others among the green left, Mr. McKibben insists that the prospect of catastrophic climate change means we must rely solely on renewable energy (and no nuclear power, either). What would that mean? Again, let's "do the math." And to keep it simple, let's ignore oil (even though it accounts for about a third of all energy consumption) and focus solely on electricity.

Over the past three decades, according to the BP Review, global electricity demand has been growing by about 450 terawatt-hours a year. And the International Energy Agency expects power demand will continue growing by about that pace for the next two decades.

What would be required if we relied on solar energy to keep up with expected growth in electricity demand? Let's look at Germany, which has more solar capacity than any other country, about 33,000 megawatts. In 2012 those solar facilities produced 28 terawatt-hours of electricity. Thus the world would have to install about 16 times as much photovoltaic capacity as Germany's entire installed base, and it would have to do so every year.

Wind? Merely to keep pace with the global growth in electricity demand would require the installation of about 280,000 megawatts of new wind-energy capacity every year. According to several academic studies, the areal power density of wind energy—that is, the amount of power that can be derived from a given amount of land—is about one watt per square meter. This means that installing the requisite additional wind capacity would require covering about 280,000 square kilometers (108,000 square miles of land)—an area nearly the size of Italy—with wind turbines, every year. (For comparison, the areal power density of nuclear power is more than 50 watts per square meter. The productivity of oil and gas wells vary, but even marginal wells have power densities of about 27 watts per square meter.)

Late last month I emailed Mr. McKibben, asking for his calculations regarding the energy-supply, land-use, or economic implications of his 20-fold reduction plan for hydrocarbons. His response included no math on the quantity of hydrocarbons available, nor any numbers for expected land use, or costs. Instead Mr. McKibben pointed mainly to a report earlier this year by Mark Jacobson, an engineering professor at Stanford University, which claims that wind, water and solar could meet all U.S. energy demand by 2050.

That document, in turn, refers largely to a 2010 paper Mr. Jacobson published in the journal Energy Policy, which rests heavily on the assumption that some type of electricity-storage system will be invented so that we can store the intermittent energy harnessed from the wind and sun. How reasonable is that assumption? Energy storage, Mr. Jacobson writes, "is a critical area for new research."

My email to Mr. McKibben also inquired about the need for refined petroleum products in transportation and aviation. His response ignored aviation but replied that "we've made great strides in electrifying vehicles." The energy he collects from the solar panels on his house, he wrote, can power his Ford C-Max on "most days."

Here's a suggestion: As a test of his scheme to cut hydrocarbon use 20-fold, Mr. McKibben and his allies making the pilgrimage to the September climate-change march, should be required to travel to New York City in solar-powered cars. If there aren't enough of those, they should be required to walk to the Big Apple.

It will be a good test. For if policy makers implement Mr. McKibben's energy plan, we'll all be walking. A lot.