The Khazzoom-Brookes Postulate

Ottawa war memorial

Reading through George Monbiot’s Heat, I encountered the idea of the Khazzoom-Brookes Postulate for the first time. The postulate relates to the effect of increasing energy efficiency on total energy usage and holds thas as the energy efficiency of industrial processes increases, total energy use actually rises as well. While initially counter-intuitive, the idea does seem to have some validity. If the energy cost of producing one tonne of aluminum falls from $5000 to $4000, you would expect aluminum companies to produce more. After all, their profit margin will have widened, all else being the same. The Celsias blog cites another example: if Boeing’s new 787 Dreamliner is 20% more fuel efficient, that just means that ticket prices will fall and more people will fly. Greenhouse gas emissions will stay the same or rise.

As Monbiot acknowledges, the postulate is controversial. It is certainly decidedly inconvenient for all the people who trot out ‘increased energy efficiency’ as the first (painless) means to combat climate change. Increased energy efficiency may be great for various reasons of convenience and enjoyment, but the postulate and accompanying logic does give one reason to doubt whether it can have a positive effect on reducing greenhouse gas emissions.

Author: Milan

In the spring of 2005, I graduated from the University of British Columbia with a degree in International Relations and a general focus in the area of environmental politics. In the fall of 2005, I began reading for an M.Phil in IR at Wadham College, Oxford. Outside school, I am very interested in photography, writing, and the outdoors. I am writing this blog to keep in touch with friends and family around the world, provide a more personal view of graduate student life in Oxford, and pass on some lessons I've learned here.

18 thoughts on “The Khazzoom-Brookes Postulate”

  1. That might be a good general rule for large continuous processes, but does not work for individual consumption things like cars. If everyone switched to a Prius, there would be GHG savings. You cannot drive two Priuses at once.

    Likewise for air conditioners, and many other objects that just have to meet a particular service threshold.

    Also, if the cost of increasing energy efficiency is comparable to the savings, there is no incentive to increase consumption. The incentives to change would have to be government action or PR.

    So the Postulate could be used to identify areas for efficiency efforts to maximise reductions.

  2. Forward, backward, inward, outward
    Come and join the chase!
    Nothing could be drier
    Than a jolly caucus-race.

    Backward, forward, outward, inward
    Bottom to the top,
    Never a beginning There can never be a stop

    To skipping, hopping, tripping
    Fancy free and gay,
    I started it tomorrow and will finish yesterday.

    Round and round and round we go
    And dance for evermore,
    Once we were behind
    But now we find we are

    Forward, backward, inward, outward,
    Come and join the chase!
    Nothing could be drier than a jolly caucus-race.

  3. “You cannot drive two Priuses at once.”

    No, but you can drive more with the same gas budget, or spend the money you save on carbon-intensive goods.

    “Likewise for air conditioners, and many other objects that just have to meet a particular service threshold.”

    Air conditioners you can run colder, and on cooler days, and for longer. Likewise, all sorts of other gadgets.

  4. I’m glad you made this post because it affords me a better forum in which to respond to the previous post you made about the Prius and how it divides people into 2 camps. As which most things, I think both “camps” are too one sided. Here is a more considered response to this notion:

    It certainly might be the case that building a better mousetrap (here metaphorized by the Toyota Prius) could help mitigate climate change while maintaining what we currently see as a positive lifestyle. However, you as much as anyone know that we do not need only metaphors but the real deal. What I mean is the Toyota Prius is a fraud: it claims to be what it is not. It claims to be an environmentally friendly auto, when actually, while it is reasonably cheap on fuel, it’s far too expensive and far to heavy for its own good. It’s not what it claims to be: a diesel would get better mileage on the highway, and be much cheaper to buy in the first place. But, it wouldn’t have the environmental “cachet”. Also, no one likes diesels.

    The thing is, we don’t need the appearence of environmentally friendly lifestyles, we need actual environmentally friendly lifestyles. But, if these lifestyles are sold to us by marketers that have a stake in them, they will inevitably perhaps, lie. And create, like in the prius, what are essentially golden calfs. (The golden calf is the original Satan – the appearence of god without really being it).

    Furthermore, if we remain within what I and others call the “will to power” mentality, where we simply aquire more power for the sake of the further aquisition of power (reading “a brief history of nearly everything” and “guns germs and steel” have solidified for me the belief that at least current understandings of world history characterize it and life itself as will to power, as simply “wanting to be”), we will obey economic laws like the one discussed in this post. A more environmentally friendly lifestyle simply means we can have more of it. This operates on both a psychic and economic level (you don’t feel “guilty” about driving more if you have a prius).

    What we need, I think, is the technology of the market but the will of sacrifice. Not even a very strong will, but monumentally strong because it must be strong enough to overcome the will to more for more’s sake which seems to govern everything. I’m not sure we can have this. Thus many people’s unwillingness to acknolege the problem of the will to power, or, having acknoledged it, strongly rejecting progress at all and instead pound leather on superhighways.

  5. The issue goes way beyond the Prius. When the Stern review says the cost of moving to a low-carbon society is likely to be 1% of GDP (ie. between -1% and plus 3%, weighted for probability), they are counting efficiency gains against the costs. Unless those efficiency gains do not rebound in the form of new emissions, as suggested by the above, the costs of mitigating climate change may be markedly higher.

  6. One thing Monbiot definitely gets right:

    “We wish our governments to pretend to act,” he writes. “We get the moral satisfaction of saying what we know to be right, without the discomfort of doing it. My fear is that the political parties in most rich nations have already recognized this. They know that we want tough targets, but that we also want those targets to be missed. They know that we will grumble about their failure to curb climate change, but that we will not take to the streets. They know that nobody ever rioted for austerity.”

  7. On the rebound

    Dec 17th 2007
    Energy pleas ignore an important bit of economics

    ENERGY efficiency is probably the most popular environmental panacea. While politicians discuss complicated global climate-change deals, economists tinker with intricate emissions-trading schemes and engineers design a new generation of nuclear-power plants, many greens advocate simpler steps: buying more efficient cars, replacing wasteful incandescent bulbs with efficient fluorescent ones and installing proper insulation. The International Energy Agency reckons that more efficient manufacturing, cosier houses and frugal transport could reduce energy demand worldwide by a third by 2050.

  8. Because fuel costs are a significant part of the total price of running a car, lowering them means cheaper motoring. And cheaper motoring, all other things being equal, means more motoring. The same applies to flying, home insulation or industrial processes: any reduction in energy use means a reduction in cost which, in turn, leads to an increase in demand, eating into the savings from more frugal engineering. In energy economics this is known as the “rebound effect.” It was first described in 1865 by William Stanley Jevons, an economist investigating steam engines.

    Since then, says Steve Sorrel, an economist who produced a report about the rebound effect for Britain’s Energy Research Centre, there has been little research into just how big the rebound effect is. Estimates of the “direct” effect range from almost zero to over 100% (ie, greater efficiency encourages so much more consumption that net energy use actually goes up).

  9. “Now that iron could be made with coal, a critical constraint on the growth of the industrial economy had fallen away. The production of coal, steam engines, and iron spiraled upward at a pace that would have made Adam Smith dizzy, and it was accelerated by the mutually reinforcing relationships that existed among the three. Steam increased the demand for both coal and iron, and also made coal and iron easier and cheaper to produce. Cheaper coal and iron made steam engines cheaper to build and run, which, in turn, attracted more people to steam power, further increasing the demand for coal and iron, and so on.

    The nation raced to open new coal mines to meet the skyrocketing demand: Between 1842 and 1856 the number of coal mines quadrupled.”

    Freese, Barbara. Coal: A Human History. p.66 (hardcover)

  10. “Local home-appliance and building contractors who specialize in green products see examples of such indulgence almost every day. They have begun to warn customers that installing green products in their homes does not give them license to overconsume: Don’t run the plasma TV all night just because you put solar panels on your roof; don’t take endless showers because your water is heated off the grid; don’t do more loads of laundry because your machine is energy-efficient.

    There is ample reason for such warnings.

    Lucas Davis, an energy economist at the University of California, Berkeley, has published a study showing that after getting high-efficiency washers, consumers increased clothes washing by nearly 6 percent. Other studies show that people leave energy-efficient lights on longer. A recent study by the Shelton Group, which advocates for sustainable consumer choices, showed that of 500 people who had greened their homes, a third saw no reduction in bills.

  11. “The light perceived by the human eye is measured in units called lumen-hours. This is about the amount produced by burning a candle for an hour. In 1700 a typical Briton consumed 580 lumen-hours in the course of a year, from candles, wood and oil. Today, burning electric lights, he uses about 46 megalumen-hours—almost 100,000 times as much. Better technology has stimulated demand, resulting in more energy being purchased for conversion into light.

    That, at least, is the conclusion of a study published in the Journal of Physics D: Applied Physics by Jeff Tsao of Sandia National Laboratories in New Mexico and his colleagues. They predict that the introduction of solid-state lighting could increase the consumption of light by a factor of ten within two decades.

    To work out what solid-state lighting would do to the use of light by 2030, Dr Tsao and his colleagues made some assumptions about global economic output, the price of energy, the efficiency of the new technology and its cost. Assuming that, by 2030, solid-state lights will be about three times more efficient than fluorescent ones and that the price of electricity stays the same in real terms, the number of megalumen-hours consumed by the average person will, according to their model, rise tenfold, from 20 to 202. The amount of electricity needed to generate that light would more than double. Only if the price of electricity were to triple would the amount of electricity used to generate light start to fall by 2030.”

  12. The light fantastic

    SIR – Your surprisingly negative article on energy efficient lighting technologies (“Not such a bright idea”, August 28th) appears to have resulted from a misunderstanding of our paper in the Journal of Physics.

    Unfortunately, your writer’s reasoning erred by comparing today’s per capita mixed light consumption with the projected 2030 consumption for all-solid-state lighting (SSL), rather than comparing the projected 2030 consumption with and without SSL. Because of this “apples and oranges” comparison, you drew a number of erroneous conclusions. For instance, you stated that in 2030 a tripling of electricity prices would be required before energy consumption for lighting declined. In fact, our paper shows that, for the two 2030 scenarios (with and without solid-state lighting), a mere 12% increase in real electricity prices would result in a net decline in electricity-for-lighting consumption. This “green” result is obtained while at the same time enabling consumers in 2030 to use three times more light with SSL than without it. Your amusing but hopefully tongue-in-cheek conclusions about the “greenness” of incandescent lighting would be, if serious, off-base and in our view potentially harmful.

    Jeff Tsao
    Harry Saunders
    J. Randall Creighton
    Michael E. Coltrin
    Jerry A. Simmons
    Sandia National Laboratories
    Albuquerque, New Mexico

  13. Do alternative energy sources displace fossil fuels?

    Richard York

    Nature Climate Change

    30 August 2011
    15 February 2012
    Published online
    18 March 2012

    A fundamental, generally implicit, assumption of the Intergovernmental Panel on Climate Change reports and many energy analysts is that each unit of energy supplied by non-fossil-fuel sources takes the place of a unit of energy supplied by fossil-fuel sources1, 2, 3, 4. However, owing to the complexity of economic systems and human behaviour, it is often the case that changes aimed at reducing one type of resource consumption, either through improvements in efficiency of use or by developing substitutes, do not lead to the intended outcome when net effects are considered5, 6, 7, 8, 9. Here, I show that the average pattern across most nations of the world over the past fifty years is one where each unit of total national energy use from non-fossil-fuel sources displaced less than one-quarter of a unit of fossil-fuel energy use and, focusing specifically on electricity, each unit of electricity generated by non-fossil-fuel sources displaced less than one-tenth of a unit of fossil-fuel-generated electricity. These results challenge conventional thinking in that they indicate that suppressing the use of fossil fuel will require changes other than simply technical ones such as expanding non-fossil-fuel energy production.

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