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Why technology alone won’t save us

Book extract, from “Managing Without Growth. Slower by Design, Not Disaster”, Sect 7.4.2, by Peter Victor, publ by Edward Elgar 2008
Part Two

The previous issue, Part One, covered two reasons why modern technology cannot be relied upon to bail us out of future environmental problems. Part Two continues, with the third and final reason and a summary. We are grateful to Elinor Hurst for compiling the two extracted parts.

The third reason why we might question how fast technological change can reduce environmental impacts is that even some of the greatest improvements in technology proceeded at quite a modest rate. A good example is the steam engine which powered the first industrial revolution in Britain and then other countries from the mid-18th to the early 20th centuries. There were steam engines before James Watt designed his in 1769. Thomas Savery built a steam driven pump in 1698 based on a design by Denis Papin. The pump was used to remove water from mines to prevent flooding.1 Thomas Newcomen improved Savery’s design by incorporating a piston inside the cylinder in which the vacuum was formed.

The first Newcomen steam engine for pumping water was installed at a coal mine in 1712. These steam driven pumps allowed deeper mines and greater access to Britain’s rich deposits of coal and other minerals. That they were extremely inefficient did not matter very much as long as they were used at coal mines where plenty of fuel was available.

When James Watt was repairing one of Newcomen’s engines he realised that he could make it more efficient by using a separate condenser to cool the used steam. In 1781 Watt designed a steam engine that could deliver rotary power rather than the up and down motion required for pumping water. Now steam engines could be used in manufacturing and because of their improved efficiency, requiring less coal to produce a unit of useful energy, factories could be located close to their markets rather than to the coal mines. The most common applications for these new and improved steam engines were in textile production, and the textile industry became a catalyst of the industrial revolution in Britain.3 Steam engines could also be used to power steam trains and by the 1840s, for the first time in history, people could move themselves and their freight faster than a horse could carry them.4

Throughout this period and beyond, many improvements were made in the design and construction of steam engines. In particular, they were made much more efficient. By 1910 the best steam engines were about 50 times more efficient than a Newcomen engine and about 12 times more efficient than a Watt engine.5 These were truly impressive gains but they did take a long time. Also there is always a delay between the timing of a technological advance and its implementation. The average efficiency of steam engines at any time was always less than the best.

A comparison of the gains in the efficiency of steam engines with the increase in installed capacity of steam engines in Britain shows that increases in scale outpaced improvements in efficiency by some 40 to 50 times.6 The increased use of coal to fuel the almost 2000-fold increase in steam power in Britain between 1760 and 1910 very likely caused a significant increase in environmental impacts as well.

Many of the most important technological advances in the 20th century involved electricity. While the pace of technological change quickened, record of efficiency gains in the use of electricity in the 20th century is far less impressive than for steam in the 19th. Total end use of electricity in the USA increased over 630 times from an estimated 5.7 bkWh7 in 1902 to 3606.5 bkWh in 2000. The average secondary efficiency of this electricity use (that is the the conversion of electricity to useful work) increased from 51.4 per cent in 1902 to 57.3 per cent in 2000, having reached 55.4 per cent as early as 1930.8

This very modest gain in the average secondary efficiency of electricity hides some larger improvements in particular uses of energy. Motors used in elevators and lighting stand out as two uses where quite considerable gains in efficiency were made. Gains were made in other uses too, almost all greater than the average. The reason why average efficiency increased so little is that the mix of uses also changed, with the least efficient uses, notably low temperature heat, increasing their share of total use. Ayres and colleagues correctly observe that using electricity to provide low temperature heat represents a promising opportunity for future gains.9 Nonetheless the potential for future gains in many uses is quite limited with efficiencies already at 70 per cent or more.

Increases in scale can overwhelm the increases in efficiency. We can even expect this to happen as increases in efficiency work their way through the economy by lowering prices. This is sometimes called the ‘rebound effect’. It is not a new idea. Jevons wrote about it in 1865 in relation to coal. “It is wholly a confusion of ideas to suppose that the economic use of fuel is equivalent to a diminished consumption. The very contrary is the truth” (italics in the original).10

For example, homeowners might respond to an increased level of insulation by keeping their homes warmer in winter and cooler in summer. In doing so they reduce the energy savings that they might have expected. A similar rebound effect is likely with the replacement of incandescent light bulbs by compact fluorescents. These more efficient light bulbs reduce the energy costs of lighting and so people may keep the lights on longer. A more subtle effect is possible too. In winter in cold climates, the heat from electric lights reduces the requirement for heat from a furnace. By using more efficient light bulbs which produce less ‘waste’ heat, furnaces will run longer unless thermostat temperatures are lowered, which is unlikely. In this case energy savings at the end-use level are partially or fully negated by the greater use of energy required to run the furnaces. If the electricity used for lighting comes from hydroelectric or some other renewable source, and the furnace is fuelled by oil or gas, then emissions of pollutants to the air would almost certainly increase.

This is a rebound effect with a vengeance.

Ayres11 has looked at the environmental implications of increasing the technical efficiency and concludes that “efficiency improvements have rarely, if ever, resulted in reduced aggregate energy (including materials) consumption”. Haberl, Krausmann and Gingrich12 have come to the same conclusion based on an analysis of data from 1700 to 2000: “At least so far, efficiency increases are more than compensated by increases in consumption levels”.

Improvements in technology can reduce environmental impacts but too much reliance on technology without attending to scale will likely prove inadequate.


  1. Karwatka, D (2007), Thomas Savery and His Steam-Operated Water Pump, Tech Directions, 66 (78), 100.
  2. Karwatka, D. (2001), Thomas Newcomen, Inventor of the Steam Engine, Tech Directions, 60 (78), 99-111.
  3. Dickenson, H.W. (1935), James Watt: Craftsman and Engineer, Cambridge: Cambridge University Press.
  4. Smil, V. (1994), Energy in World History, Boulder, CO: Westview Press.
  5. Ibid Figure 5.3, p. 164.
  6. Crafts, Nicholas (2003), Steam as a General Technology: A Growth Accounting Perspective (Unpubl manuscript), Working Paper 75/03, London School of Economics.
  7. bkWh stands for billion kilowatt hours.
  8. Ayres, R.U, L.W. Ayres and V. Pokrovsky (2005), On the Efficiency of US Electricity Usage since 1900, Energy, 30, 1128-1154.
  9. Ibid p. 1131.
  10. Jevons, W.S. (1865), in A.W. Flux (ed), The Coal Question: An Inquiry Concerning the Progress of the Nation, and Probable Exhaustion of our Coal-Mines, NY: A..M.Kelley.
  11. Ayres, R.U. (2005), Resources, Scarcity, Technology, and Growth, in R.D. Simpson, M.A. Toman and R.U. Ayres (eds), Scarcity and Growth Revisited, Washington DC: Resources for the Future, pp. 142-154.
  12. Haberl, H., F. Krausmann and S. Gingrich (2006), Ecological Embeddedness of the Economy, Economic and Political Weekly, November 25, retrieved August 19/07, online:

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