If we could make coal plants, natural gas facilities, and gasoline engines so efficient that they could extract 90% of the energy (roughly 3 times the current amount) stored in fossil fuels, would our environmental woes be solved?
Assuming society’s total energy use stayed exactly the same, then we could cut emissions by as much as 66%. That would be extremely significant. However, when energy can be extracted more efficiently, that energy becomes cheaper, and when energy is cheaper people consume more of it. This is known as the Rebound Effect and it means that improving efficiency could lead to greater energy consumption.
The rebound effect has been a very hotly contested topic in the academic community for the last 40 years. The intensity has increased more recently as climate change has become an important global issue. The consensus is that the rebound effect is real, but the magnitude of the rebound is under serious debate and may be categorized as follows1:
- Super conservation – more resources are saved than expected
- Zero rebound – as many resources are saved as expected
- Partial rebound – fewer resources are saved than expected
- Full rebound – no net resources are saved or consumed
- Backfire – resource consumption has increased
In our example, a 66% reduction in energy use would be a zero rebound scenario because as many resources are saved as expected, an ideal outcome. Nobody is debating whether this occurs because everyone agrees that some form of rebound happens. The debate is whether the rebound is small and say 90% of expected resources savings are achieved, whether it is large and only 10% of expected resource savings are realized, or whether more resources are being used than were previously.
The rebound concept was first described by William Stanley Jevons in the 1865 book “The Coal Question.” At the time, James Watt had recently invented the Watt Steam Engine, which was significantly more efficient than the previous engine in use. According to Jevons, this increase in efficiency resulted in a much broader range of industries using the steam engine than before and caused an overall increase in the use of coal in the UK. Thus Jevons paradox, as it was coined, is an extreme rebound that has reached a backfire condition.2
Unaware of Jevons paradox, Dr. Daniel Khazzoom and Dr. Len Brookes came to similar conclusions when researching appliance efficiency and energy efficiency, respectively, in the 1980s. The same thing happened in 1992 when Dr. Harry Saunders created a model incorporating energy efficiency into neoclassical growth theory and was shocked to see the model predict increases in energy use when energy efficiency increased. He then began researching prior knowledge in the subject found that Khazzoom and Brookes had described the same concept 10 years earlier, thus he named it the Khazzoom-Brookes postulate. Only later did he discover that Jevons had beat him by over 100 years.3
Why it Happens
The reasons for the rebound are attributable to three economic considerations: direct, indirect, and economy wide effects. A direct effect is increasing the use the specific resource because one can now afford to do so (i.e. traveling more due to cheaper fuel). Indirect effects are increasing spending in other areas because one now has more income (i.e. buying more clothes because one now has more money due to cheaper fuel). Economy wide effects are the increase in societal consumption due to the improved economy that resulted from efficiency improvements.4
It is the attempt to measure the size of each of these effects that results in so much debate around the subject.
What Determines the Magnitude of Rebound
The country in where the efficient technology is implemented can have a significant effect because of the maturity of the industry. For example, in America the use of energy is already very high, therefore increasing the efficiency at which energy is generated will have a smaller effect than if the same new energy efficient technology was implemented in a developing country where there is a larger consumer base that will have new uses to apply cheaper energy.5
The peculiarities of the customer have a similar effect. If a wealthy individual already puts his/her thermostat at the optimal temperature then a decrease in electricity prices will not result in an increase in energy use because the individual was already using the maximum amount possible. However, for a low income family, a reduction in electricity costs may result in thermostat settings at a more comfortable level.6
Finally, the sector in which the efficiency improvement occurs affects the magnitude of the rebound. For example, a rebound effect is likely higher for steam engines or electric motors than for thermal insulation.4
What is the Evidence of Rebound
Those who would say that the rebound is significant point to measures such as a 37% increase in total national air conditioning energy use between 1993 and 2005 when air conditioners became 28% more efficient.7 However, looking at the same set of data, another might say that the increase in the use of air conditioning equipment is due to the fact that income (adjusted for inflation) increased by 30% and the average new home was 16% larger in 2005 than 1993.8 This is precisely the opinion of Dr. Jim Barrett, Chief Economist at the Clean Energy Development Center. Delving deeper into the problem, some economists, such as Dr. Saunders, say that this is where energy efficiency advocates fail, because they are looking at energy in isolation without considering that materials or labor may be substituted by energy use.3
In another example, David Owens points out that refrigerator size increased in the 60s and 70s with the increase in refrigerator efficiency, and suggested that increased efficiency enabled larger refrigerators to become affordable.7 David Goldstein, Co-Director of the Energy Program at NRDC, points out that Owens is incorrect because refrigerator size increased even as efficiency decreased in the 1950s and 60s.9 However, these analyses have narrowed their scope too far and focus only on direct effects. Perhaps some combination of other products became cheaper during the 50s and 60s due to improved manufacturing or energy efficiencies. This would leave the consumer with more money in their pocket, which means they could choose to spend more on something such as a refrigerator. This is the exact definition of an indirect effect where people choose to spend more on something else (refrigerators in this case) because they saved money elsewhere. This is a self serving argument for rebound enthusiasts that would make it even more difficult to prove anything regarding a rebound effect, but it highlights the difficulty of rebound analysis.
Governmental Research Efforts
A research effort undertaken by the UK Energy Research Centre in 2007 established that much of the data necessary for quantifying the rebound effect is difficult, if not impossible to obtain, including effects on capital, labor, and materials used, which may amplify the rebound. They concluded that the approximate rebound effect in developed countries is around 10% and 50% or higher in developing countries. However, it should be noted that their confidence level in their conclusions is very low due to the lack of data.4
As expected, this conclusion is seriously contested by both sides because it strikes more of a middle ground on the issue. Amory Lovins, Chief Scientist at Rocky Mountain Institute, says that rebounds are in the range of zero percent to just a few percent.9 While Dr. Saunders would suggest that the rebound is 50% to 60% in the US.3 Interestingly, Amory Lovins says that energy efficiency offers an “economic bonanza because saving fuel is a lot cheaper than buying it.”9 This would seem to support the position that energy efficiency could rebound because of all the extra money consumers and corporations save, yet he does not believe the rebound is significant.
A major part of the argument rebutting Jevons paradox is the fact that energy consumption only accounts for roughly 6% of GDP, therefore any direct savings from efficiency spent on other goods would still be saving 94% of the claimed savings.7 However, this logic is questionable because as energy efficiency increases, society spends less on energy, but society is even more dependent on it.
Who is Right?
Well, there wouldn’t be a debate if we knew who was right. However, the debate might be better served to be re-centered around another question: how much does energy efficiency increase the size of the economy?
The paradox is difficult to prove or disprove because so many studies focus on the effect of one product or one consumer, but the effect is observed at the macroeconomic scale. However, it is clear that some level of rebound exists and that rebounds are different product to product and country to country.
That argument is possibly best summarized by Steve Sorrell, senior fellow at Sussex University, “I think the point may be that Jevons has yet to be disproved. It is rather hard to demonstrate the validity of his proposition, but certainly the historical evidence to date is wholly consistent with what he was arguing.”7
The rebound effect is very similar to a concept called induced demand from the transportation industry. In transportation planning, engineers and planners are confronted with problem that when traffic congestion is relieved on one road (by the addition of lanes or constructing trains that run parallel to the road) more people choose to use that road, more people move to that area, and people begin use that road from a longer distance out; all causing that road to return to a similar or greater level of congestion than it previously had. Currently, there is no great solution to this problem, though tolls have begun to show a positive effect. Perhaps the same solution is necessary for energy efficiency, greater taxes on energy use when we use more energy.
This thought process naturally leads to the notion that the cost of energy must be manipulated to reduce or eliminate the rebound effect. A tax solution for our environmental woes associated with energy use could be a carbon tax. A carbon tax will stimulate development of more efficient fossil fuel technologies and renewable energy. Plus it will counter the natural rebound effect that occurs. For example, if it cost me $100 to operate my car, then a carbon tax was implemented that increased that cost to $150, then I would be more inclined to purchase a more fuel efficient vehicle or drive fewer miles to bring my cost back down to $100. In that scenario, when I bring my energy use down, I would be spending the same amount as I had been originally, but using 33% less fuel (assuming a linear price elasticity). A carbon tax that escalates over time can ensure that the price of energy remains the same even as we are using less of it.9
Renewable energy is clearly one of the better solutions if the rebound has any kind of an effect, but even more so if the rebound is significant. If policies and programs designed to improve efficiency end up meaning society uses more energy, then the policies will fail to to reduce our carbon emissions.
Interestingly, cheap renewable energy has its own rebound issues based on the same economic principles as Jevons paradox. For example, a solar customer who sees their bill go to zero may increase their energy use because they can afford to do so. However, it is impossible for this rebound to be 100% because solar energy isn’t free. Thus if an individual were paying $100 per month on electricity, and then a new solar system reduces their bill to $20 plus $50 per month on their solar payment plan, the maximum that they would rebound is $30, assuming all other factors stay the same. This would be a rebound of 37.5% ( = 30 / 80), which is clearly not ideal, but far from a Jevons scenario of over 100%.
It is important to note that even this situation highlights the Jevons paradox though. Using the same example from before, if solar panels are more efficient, then the cost per unit of energy is lower. Thus if the individual who was paying $100 per month is now paying $20 plus $40 per month on their payment plan for more efficient solar panels. Then they could rebound a maximum of $40, which would be a rebound of 50% (= 40 / 80).
Nevertheless, technologies that do not produce emissions will clearly have a beneficial effect on the environment regardless of the rebound because we are increasing the percentage of environmentally friendly energy in the global mix. Plus, once the carbon emissions problem is solved, then energy efficiency can go back to doing what it does best: improving welfare.
- Saunders, Harry D. “Fuel conserving (and using) production function”. Energy Economics. 2007.
- Garrett, Tim. “Rebound, Backfire, and the Jevons Paradox”. University of Utah. 2014. http://www.inscc.utah.edu/~tgarrett/Economics/Jevons_Paradox.html
- The Breakthrough. “Understanding Energy Efficiency Rebound: Interview with Harry Saunders”. The Breakthrough. 23 Jan 2013. http://thebreakthrough.org/index.php/programs/energy-and-climate/understanding-energy-efficiency-rebound-interview-with-harry-saunders
- UK Energy Research Centre. “The Rebound Effect: an assessment of the evidence for economy-wide energy savings from improved energy efficiency”. 2007
- The Breakthrough. “Understanding Energy Efficiency Rebound: Interview with Joyashree Roy”. The Breakthrough. 23 Jan 2013. http://thebreakthrough.org/index.php/programs/energy-and-climate/understanding-energy-efficiency-rebound-interview-with-joyashree-roy
- Milne, Geoffrey and Boardman, Brenda. “Making cold homes warmer: the effect of energy efficiency improvements in low income homes”. Energy Policy. 2000.
- Owen, David. “The Efficiency Dilemma”. The New Yorker. 20 & 27 Dec 2010. http://www.newyorker.com/magazine/2010/12/20/the-efficiency-dilemma
- Barrett, Jim. “Debunking the Jevons Paradox: Nobody goes there anymore, it’s too crowded”. Think Progress. 16 Feb 2011. http://thinkprogress.org/climate/2011/02/16/207532/debunking-jevons-paradox-jim-barrett/
- Rocky Mountain Institute. “Jevons Paradox: The Debate That Just Won’t Die”. Rocky Mountain Institute”. 20 Mar 2012. http://blog.rmi.org/blog_Jevons_Paradox
- Goldstein, David B. “Some Dilemma: Efficient Appliances Use Less Energy, Produce the Same Level of Service with Less Pollution and Provide Consumers with Great Savings. What’s Not to Like?”. NRDC. 18 Dec 2010. https://www.nrdc.org/experts/david-b-goldstein/some-dilemma-efficient-appliances-use-less-energy-produce-same-level