The idea that there are untapped opportunities for improving the energy efficiency of individuals and homes is common. Energy efficient windows, lightbulbs, and appliances are sold worldwide. People are advised to “turn off the lights when you leave a room,” and schemes have been introduced to reduce energy consumption by tapping into social psychology. But what about large firms? Or entire industries? Companies, after all, want to minimize costs to save money, don’t they? How about airlines, whose bottom lines are subject to the international price of fuel?
It seems rational, but the International Energy Agency does not mention the aviation sector in its Energy Efficiency Market Report, nor does Kinsey in their comprehensive catalog of potential energy efficiency measures. Most reports (that I could find) focus on regulation of commercial enterprises. This is a shame. The environmental impact of aviation is clear: aircraft engines emit heat, noise, particulates, CO2, and other harmful gases that contribute to climate change. Despite more fuel-efficient and less polluting turbofan and turboprop engines for airplanes as well as innovations in air frames, engines, aerodynamics, and flight operations, the rapid growth of air travel in recent years has contributed to an increase in total aviation pollution. In part, this is because aviation emissions are not subject international regulation thus far and because the lack of global taxes on aviation fuel results in lower fares than one would see otherwise.
Interestingly, although perhaps not surprisingly, the National Bureau of Economic Research just released a working paper that suggests airlines’ fuel consumption can be reduced if they “nudge” the pilots to use less fuel, using behavioral interventions.
Greer Gosnell of the London School of Economics and Political Science and University of Chicago economists, John List, the Homer J. Livingston Professor of Economics, and Robert Metcalfe, Becker Friedman Institute research scholar partnered with Virgin Atlantic Airways to conduct an experiment to explore how information and incentives might affect the choices pilots make. The study included over 40,000 unique flights made by 335 pilots covering an eight-month period in 2014
Fuel use was measured during three separate flight phases: before a plane takes off, while it is operated in the air, and then on the ground post-landing. The pilots were randomly assigned to four separate groups which received either (1) monthly assessments about average fuel efficiency on the flights the pilot made in the previous month, (2) the same personalized information as group 1 plus personalized targets for the coming month and praise when they succeeded or more encouragement to do better if they didn’t, (3) the same personalized information as group 1 and targets like group 2, plus an offer to donate 10 GBP (which was worth more pre-Brexit…) to a charity for each target achieved, or (4) notification that the experiment was taking place but didn’t receive a monthly mailing (comparison group).
All four groups increased their implementation of fuel-efficient behaviors, demonstrating that informing pilots of their involvement in a study significantly changed their behavior. Even pilots in the comparison group (group 4) improved their fuel efficiency considerably relative to the months before the study began. The authors speculate this is an example of the Hawthorne Effect, which suggests that people behave differently when they know they’re being studied.
Pilots who only received information (group 1) significantly improved their fuel efficiency, and pilots who received personalized targets (group 2) or who received targets and charitable donations (group 3), improved their fuel efficiency even more.
Most importantly, the intervention appears to induce habit formation, as fuel efficiency measures remained in use after the study ended.
Contrary to expectations based on prior studies, charitable contributions for meeting targets did not further change behavior, but captains in this group did report 6.5 percent higher job satisfaction than captains in the other groups.
In terms of fuel consumption, the experiment saved 6,828 tons of fuel for Virgin Atlantic, worth GBP3.3 million, according to the airline. This prevented the emission of 21,507 tons of carbon dioxide to the atmosphere.
The costs of running the experiment, moreover, were very low – less than $3,000 to send a couple hundred letters a month. The authors calculate that the intervention produced savings estimated at $250 per metric ton of CO2 abatement.
Indeed, the intervention was so cost effective, the researchers say, that it “outperforms every other reported carbon abatement technology of which we are aware” (page 4).
So, what adjustments did the pilots make to save fuel? As it turns out, pilots have a great deal of control over how much fuel they burn per flight, and most of the improvements involved simply – ahem – following the rules. For example, when taxiing, pilots are usually supposed to turn off half of the engines (e.g., one on a two-engine plane and two on a four-engine plane). Before the experiment, pilots did so on 35% of the flights, and, this increased to 51% after they knew they were being observed. Other adjustments include following the advice of air traffic control about more efficient routes or using information about baggage onboard to adjust fuel levels.
While the fuel savings are statistically significant, they amount to small tweaks to the way the airline does business. Many scientists and policy advocates continue to call for “deep cuts in emissions levels (not just growth rates) over the next few decades that would hold the likely increase in global temperature closer to 2°C.” A 2°C trajectory, though, would require extraordinary mitigation efforts so while very little bit certainly helps, we cannot stop looking for more fundamental changes within sectors. Let’s hope more companies take similar opportunities to find savings this way but also remember that real change will require more than following the rules.
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Photograph of plane landing by Aero Pixels via Flickr
Photograph of plane taxiing by Caribb via Flickr