Madam, – Your Editorial entitled “Gas guzzlers” (February 2nd) is based on a very simple hypothesis, namely that increased fuel efficiency leads to lower consumption. It is worth pointing out that economists have long understood that this hypothesis is rarely realised in practice.
In the 19th century it was observed that the increased efficiency of Watt’s steam engine lead to increased consumption of coal because the cost-effectiveness of coal increased. This paradox is also known as the Khazzoom-Brookes postulate, where it was used to describe how energy efficiencies at the micro-economic level can lead to greater economic growth and hence increased energy consumption at the macro-economic level.
It is clear, therefore, that any measures to improve fuel efficiency in cars must be coupled with measures to decrease fuel consumption for the population as a whole. – Yours, etc,