Is Subsidizing Electric Cars an Effective Way to Slow Climate Change?

Some governments have been subsidizing purchases of electric vehicles, or more broadly, fuel-efficient vehicles to slow climate change. How well do such policies work? Are they more or less efficient than other policies intended to reduce carbon dioxide emissions? 

A subsidy is a payment by the government that provides an incentive for people to take an action they otherwise wouldn’t, such as buying an electric car. Subsidies have the potential downside that they may involve payments to people to do something they would have done anyway.  For instance, in the United States in 2021, buyers of electric cars were eligible for a credit of up to $7,500 against their federal income taxes. Suppose that you become aware of this subsidy only after you have already purchased an electric car. In that case, the federal government has wasted $7,500 because you would have bought the electric car even without the subsidy. The same would be true if you knew about the subsidy before you bought but because of the subsidy you bought a higher-priced electric car rather than a lower-priced one.

These complications make it difficult for policymakers to assess the efficiency of subsidizing fuel-efficient cars as a means of slowing climate change. Two recent academic papers address this difficulty.  

Chia-Wen Chen of Academia Sinica in Taiwan, We-Min Hu of National Chengchi University in Taiwan, and Christopher Knittel of the Massachusetts Institute of Technology have analyzed a Chinese government program that subsidizes the purchase of fuel-efficient cars. Because the study used data from 2010 and 2011, these vehicles were fuel-efficient gasoline powered cars rather than electric cars.  They find that only about 44 percent of the subsidies went to car buyers who would otherwise not have bought a fuel-efficient car. “Thus, about 56 percent of the program’s payments were ineffective ….” 

The authors calculate that the subsidy cost about $89 per metric ton of carbon dioxide reduced, which is high relative to other policies, such as a carbon tax. With a carbon tax, the government taxes energy consumption on the basis of the carbon content of the energy. (We discuss a carbon tax in the opener to Chapter 5.) The authors conclude: “Paying more than $89 for a metric ton of carbon dioxide is not a cost effective way to reduce carbon dioxide; if the main policy objective of China’s subsidy program on fuel-efficient vehicles was to reduce carbon dioxide emissions, then our results suggest that it was an ineffective way to achieve this goal.”

Jianwei Xing of Peking University, Benjamin Leard of Resources for the Future, and Shanjun Li of Cornell University analyze the efficiency of the U.S. federal income tax credit for purchasing an electric vehicle. As with the study just discussed, they find that consumers who use the credit to buy an electric vehicle were likely to have otherwise bought a hybrid vehicle (a vehicle that combines an electric motor with a gasoline engine) or a relatively fuel-efficient gasoline powered car. They also find, as with the other study, that the federal subsidy is inefficient because while it increased electric vehicle sales by 29 percent, “70 percent of the [tax] credits were obtained by households that would have bought an EV without the credits.”

Because the design of a particular subsidy for buying an electric car will affect the subsidy’s efficiency, these studies are not conclusive evidence that all programs of subsidizing electric cars will be inefficient. But their results show that two existing programs in large markets—China and the United States—are, in fact, inefficient.  

As we note in Chapter 5, many economists favor a carbon tax as a way to reduce carbon emissions rather than policies, such as the federal electric vehicle tax credit, that target a particular source of carbon emissions. Economists can contribute to debates over public policy by using economic principles to identify programs that are more or less likely to efficiently achieve policy goals. They can also, as the authors of these two papers do, use statistical methods to analyze the effects of particular policies. 

Sources: Chia-Wen Chen, We-Min Hu, and Christopher R. Knittel, “Subsidizing Fuel-Efficient Cars: Evidence from China’s Automobile Industry,” American Economic Journal: Economic Policy, Vo. 13, No. 4, November 2021, pp. 152-184; Jianwei Xing, Benjamin Leard, and Shanjun Li, “What Does an Electric Vehicle Replace,” National Bureau of Economic Research, Working Paper 25771, February 2021.

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