What an Energy-Efficiency Hero Gets Wrong about Carbon Taxes

It’s rare that critiques of carbon taxing are as quantitative as the post last month by David Goldstein on the Natural Resource Defense Council’s Searchlight blog.

Goldstein qualifies as a genuine energy-efficiency hero, in my book. He has spearheaded NRDC’s pioneering analyses of appliance engineering, manufacture and marketing since the 1970s and guided the council’s strategic interventions in utility governance and energy standard-setting in California and at the federal level. This in-the-trenches work has slashed power consumption and carbon emissions from refrigerators, air conditioners, light bulbs and building envelopes in all 50 states. Goldstein’s 2002 MacArthur Foundation “genius award” was richly deserved. (The Washington DC-based American Council for an Energy-Efficient Economy, ACEEE, merits a shout-out as well.)

Befitting his analytical bent, Goldstein’s critique sticks to the high road. No self-fulfilling taunts about carbon taxers’ naivete or the tax’s political infeasibility. His post does drag out a straw man, though, insisting up-front that “carbon emissions fees alone cannot solve the climate problem” — a position held by few carbon tax advocates. (We ourselves “recommend carbon taxes in addition to energy–efficiency standards.”) His criticism sharpens at the end: “In summary, carbon pollution fees, as a stand-alone policy, are incapable of doing much to solve the climate problem.”

Goldstein has certainly thrown down the gauntlet. He has four main arguments, which I’ll treat in order. Some math is involved, but it’s central to the issue.

Argument #1: Carbon Taxes Must Raise U.S. Energy Prices 44-Fold to Meet Our Carbon Targets

Let’s start with an assertion by Goldstein that is startling but accurate — mathematically:

If we wanted energy demand to drop by 85 percent [the minimum required for the U.S. to meet IPCC temperature-rise targets] due to price, the math behind elasticities shows that we would require a price increase of 44 times. This is an impossibility condition. (emphasis added)

Price-elasticity is how economists denote the extent to which a rise in price causes demand or usage of a good or service to diminish. Assuming, as Goldstein does for argument’s sake (and as we do in modeling carbon taxes), that the price-elasticities of the various forms in which energy is used in the U.S. have an average value of minus 0.5, then a doubling of energy prices, whether effected through a carbon tax or market fluctuations, will cause energy use over time to shrink by 29 percent. (See sidebar for calculations.) With two doublings in price, the shrinkage would be 50 percent.

Elasticity math. You can do it.

Elasticity math. You can do it.

Note that the second doubling in price produces less of a decrease in usage than the first, reflecting the famed Law of Diminishing Returns. Indeed, three doublings, increasing the price 8-fold, would only bring about an overall 65 percent drop in usage. To hit the 85 percent reduction target requires a 44-fold energy-price rise. Goldstein’s math is spot-on.

But not the use to which it is put. While an 85 percent reduction in energy use would indeed cure the United States’ carbon obligations (not to mention protect and conserve air, water and land), it far exceeds what’s required, thanks to the ongoing and parallel reduction in the carbon intensity of energy supply. This decarbonization of supply is prominent in energy and climate discourse, and has been evident in the electricity sector over the past decade. Measured as pounds of CO2 emitted per kWh generated, the emission rate for all electricity generated in the U.S. last year was 16 percent less than the rate in 2005. For that we can thank increased generation from lower-carbon natural gas and zero-carbon wind. (Solar electric generation, though growing very fast, started from a tiny base and wasn’t a notable factor in the decarbonization to date.) Energy efficiency has helped as well by reducing the need to fire up high-carbon coal plants.

A carbon emissions tax, which by its nature favors wind and solar over gas, and gas over coal, will help sustain and accelerate this encouraging supply-side trend. [Read more…]


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