Powering or de-powering future vehicles to reach low carbon outcomes: the long term view 1930–2020

Government in UK has long sought to influence both new vehicle fuel efficiency and to encourage domestic car production. Sixty years of data on the change in car characteristics and fuel economy are analysed. Vehicle specific power has doubled in that time and sales of vehicles have grown preferentially in larger engine classes. New cars sold over the period 1970–2000 have a sale price of £150 per bhp at year 2000 prices. A new theory is proposed that the primary driver for increased power of vehicles, and hence CO2 production, is the increase in sale price necessitated by uneconomic production of steel vehicles in mature markets. The standard fuel test cycle shows inverse fuel efficiency relationship with weight and with vehicle power. Primary CO2 reduction targets such as the Kyoto agreement are dimensioned as outputs of energy use per unit time (power); secondary targets such as the ACEA voluntary agreement of 140 g/km in 2008 based on energy per unit distance (efficiency). Failure to focus policy on the key variable of vehicle power has allowed power to continue to increase and inhibit fuel efficiency from meeting the voluntary agreement targets. This power ‘loophole’ in Europe is likened to the emergence of light trucks in response to CAFE standards in USA. New body materials offer the prospect of profitable car production, consumer satisfaction and large reductions in CO2. New policy directions are proposed as a result of the failure of the ACEA voluntary agreement and the real importance of achieving annual CO2 reduction including via Cars 21.