Strange but true: energy efficiency actually increases overall energy use

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Posted Feb 17 2016 by Andrew Rollinson of Blushful Earth

In the 1960 film School for Scoundrels, which is based on the Stephen Potter “Gamesmanship” books, there is a scene where Ian Carmichael (formerly one of life’s failures) is playing tennis with Terry Thomas. Carmichael has just finished a course in lifemanship and, having used a series of tricks and ploys to disorientate his opponent, stands in one spot with one hand in his pocket while nonchalantly hitting the ball such that Thomas has to race, panting and exhausted, from side to side across the court. Thomas = effort, Carmichael = efficiency; do not confuse the two.


Governments are putting lots of effort into promoting efficient machines as a solution for countering global warming. Colour-coded displays encourage shoppers to compare the energy efficiency of competing appliances and gadgets; the message being that buying a higher efficiency machine can save you money and the environment. At a different level, the UK’s position in Paris last year was that global warming could be tackled by replacing existing technology with newer (and therein lies the problem) more efficient innovative products. It openly stated that this will allow UK business to sell more new technology to the developing world (1). One doesn’t have to be very astute to see that these policies cost little to implement and that they encourage consumption, sales, shareholder profits and tax income; but is there any substance to the claims that replacing existing technology with something that is more efficient can have an impact on climate change? The word “efficiency” has been adopted without adequate explanation or definition and appears to be a new “green”.

In the Oxford English Dictionary “efficient” is described as “productive with minimum waste or effort”, and in my job as an energy engineer I am used to working with the term. It is standard practice to calculate mechanical, thermal, and fuel efficiency, for example.

Efficiency is a quotient and it is useful because it permits the production of measured results by which systems can be appraised and compared. In fractional notation, the output is the numerator and the input the denominator (cf. equation below). Therefore, as with any fraction, increase the numerator while keeping the denominator fixed (so increase output per unit input) and system efficiency increases. Conversely, efficiency will also increase if the numerator is fixed but the denominator is decreased (this time reducing the required inputs for the same output).


Many calculations of energy system efficiency were developed a couple of centuries ago during the Industrial Revolution, first with water power and then with steam engines. But, efficiency calculations have much broader applications. For environmental impact appraisal, total life cycle analyses can be factored in, or for simpler single units, back-of-an-envelope calculations can include factors such as maintenance costs and service contracts, all of which increase the denominator value. Thus a new machine or process method may have an efficiency improvement only at face value. It can be worse environmentally and financially if it doesn’t operate as reliably as a less efficient model, or it has higher inputs of energy from cradle to grave.

Efficiency can also be used to qualify other aspects of life. There are economic efficiencies, i.e. income per total expenditure on resources, etc. There are also human and social efficiencies, i.e. success per unit of effort expended. And they can be interconnected: one person’s efficiency loss can result in another’s gain, which is why the internet is seen as cost effective to business. Try for example considering how much of your time is given up to bureaucracy, chasing up incompetence, searching online for savings, writing job applications (all denominator terms). Compare it with the numerator and assess how much of your time is your own, how creative have you been, how much useful or beneficial activity have you managed in comparison. Apply this to the human species in general and it becomes clear how wasteful, inefficient and enslaved we are.

In nature, efficiency usually dictates whether a species ultimately survives of becomes extinct (trophic levels, and energy expenditure for example). It derives from the universal laws of thermodynamics, where everything tends to disorder, and the more stages or levels there are in a food chain or process leads to a multiplication of inefficiency. This is why vegetarianism is better for the environment, and why grid-supplied electricity has such a low efficiency due to multiple heat losses through the raising of steam and the transmission system.

Now, because efficiency can be quantified, an answer to the question of whether efficient machines and appliances can have an impact on cutting global warming can be obtained. And, it turns out that the supposition is flawed. One reason is because of the laws of thermodynamics. No machine can ever be 100% efficient. In fact, even the best machines are less than 50% efficient. So, by making and operating more of these machines, the overall inefficiency and hence greenhouse gas emissions must increase; and that result is excluding the energy needed for production, transportation, marketing, and landfill, all of which must be included in the denominator term for accuracy.

The logic can be equally flawed at the singular level. Replacing an old system that operated at say 30% efficiency, with a newer model that operates at say 34% efficiency (yes, the differences are that small), but only lasts a fraction of the time before needing repair at best (most modern circuited systems are not built for repair) increases the overall inefficiency.

If you buy gas and electricity from the grid and have ever wondered why, with all these efficient systems and smart meters, your bills have not decreased over the years, then these are some of the reasons. There is also the fact that you are now paying an extra 9% on your bills for government-imposed incentives such as subsidising privately-owned power stations to import biomass (that’s another inefficiency story). But there is a further, more subtle reason which again is important for considering whether “efficiency” claims are credible. It is called the Jevon’s paradox.

One hundred and fifty years ago, during the Industrial Revolution in Britain, William Jevons observed that all the striving to increase efficiency and reduce costs merely resulted in more consumption of coal. The reason, he identified, was that the increased savings from efficiency were returned through commercial upscaling in the constant pursuit of profit (2). This is as true now as it was then. In the modern context, when people have an awareness that they are making savings through efficiency, they choose to be a bit less frugal with their energy saving lifestyle or, assisted by commercial encouragement, they buy new energy-consuming gadgets. The extent of how much the Jevon’s paradox dilutes greenhouse gas emissions savings is estimated to vary over a wide range from 3% to 60% (3).

So what can be done? Efficiency can save us, but only if the free-thinking individual realises that they have some freedom to make choices which in full or part can detach themselves from this present system. Decrease the denominator term of the efficiency quotient, and be wise enough to see past the gamesmanship.

Andrew Rollinson


1. H.M. Government, 2014. Paris 2015 Securing our prosperity through a global climate change agreement, DECC, Whitehall. Available from:

2. Jevons, W.S., The coal question; an inquiry concerning the progress of the nation and the probable exhaustion of our coal-mines (2nd ed), 1866, Macmillan and Co, London.

3. Gillingham, K., Kotchen, M.J., Rapson, D.S., Wagner, G The rebound effect is overplayed, Nature, 2013, 493, pp. 475-476.