What source of energy do Americans think affects the environment the most?

One of the questions we ask during the Energy Survey is about what source of energy Americans think affects the environment the most. This question is the third in a sequence that probes views on the environmental dimensions of energy (see our questionnaire here).

We first ask each respondent how much he or she believes that energy affects the environment. Based on the latest data, 77 percent of Americans say that they think energy affects the environment at least at fair amount, in contrast to 20 percent who say it affects the environment only a little and 3 percent who don’t believe energy use affects the environment at all.

We next ask about the aspect of the environment that they think is most affected by energy use. Based on their answer to that question, we then ask the respondents what source of energy they think is most responsible. This question is posed in a completely open-ended fashion; the university’s professional telephone interviewers do not recite a list of energy sources from which to choose or otherwise prompt a respondent for an answer. The results are shown in the following chart, which tracks consumer responses over the first three years of the U-M Energy Survey. The most frequent answer is some form of petroleum, reflecting responses of petroleum, oil or a petroleum product such as gasoline. Although the number of respondents who fingered petroleum varied over the three years of quarterly samples shown, no clear trend is apparent. On average, 36 percent of consumers said that some form of petroleum was the source of energy that affected the environment the most.

It turns out that, according to the U.S. Energy Information Administration (EIA), petroleum accounted for an average of 36 percent of U.S. energy consumption over the past three years. A plot of the EIA statistics, given in Quads (quadrillion British thermal units) per year is given below. Although the role of any particular fuel depends on the particular environmental impact of concern, petroleum consumption was responsible for about 40 percent of energy-related CO2 emissions over the past three years.

Because we did not prompt consumers with a list of energy sources, some answered “fossil fuels” in response to the question, without saying which fossil fuel they might have hand in mind (if any). That generic fossil fuel answer, shown by red line in the first chart, was given by 9 percent of respondents on average. Coal was the response given by an average of 17 percent of respondents when asked what source of energy they think affects the environment the most. As seen in the chart of EIA data, coal use has declined markedly over the past decade, accounting for 14 percent of U.S. energy use as of last year. Mainly used for generating electricity, coal has been largely displaced by natural gas, which accounted for 29 percent of America’s energy use as of last year. Renewable power production has also been on the rise, as wind, solar and geothermal sources (green line on the chart) came to provide 3 percent of U.S. energy based on the most recent annual data.

Of course, burning coal impacts the environment more than natural gas, emitting nearly twice the amount of carbon dioxide per unit of energy than gas, for example. An average of just under 7 percent of consumers said that natural gas was the energy source that affects the environment the most, probably reflecting the belief that natural gas is more benign than other fossil fuels. In fact, however, natural gas has recently overtaken coal in terms of nationwide CO2 emissions, now accounting for about 27% of U.S. energy-related CO2 (not including other effects, such as methane emissions).

Again reflecting the open-ended nature of our question, an average of 13 percent of consumers identified electricity as the source of energy that most affects the environment. A similar number gave a response that fell into the “Other” category as we graph it here. That includes responses identifying nuclear or some form of renewable energy, or other generic responses (such as simply “pollution”) that consumers gave when we asked the question.