Can we deliver decarbonised road transport?


While there is increasing public scepticism with regard to climate change the majority of people still believe the world is warming up and the majority of those believe that this is due to human activity. However, there is little understanding how, if at all, our use of transport might change as a result of the Government’s ambitious targets to reduce the level of carbon emissions.

The Climate Change Act 2008 established binding emissions targets and five yearly carbon budgets to reduce greenhouse gas emissions by at least 80% by 2050. The level of the first three carbon budgets for the periods 2008-12, 2013-17 and 2018-22, require respectively a 22%, 28% and 34% reduction in greenhouse gases compared to 1990 levels.

Domestic transport accounts for 23% and international transport for a further 7% of the UK’s 584m tonnes of CO2 emissions in 2007. Transport is an area where carbon emissions have increased markedly since 1990 with road transport emissions up by 11%, international aviation emissions more than doubled and domestic aviation emissions are up by 75%.

The government has set out its strategy on carbon reduction in transport. With the usual lack of transparency in the whole field of climate change this aims to deliver a 14% reduction in emissions from transport (from a 2008 base) by 2020. Why isn’t the target x% on 1990 by 2022 to fit in with the general emission targets? In reality, the 2020 target for transport is to restore emissions from transport back to 1990 levels. For 2050 the government’s vision is for surface transport to be effectively decarbonised.

These targets rely heavily on technology changes rather than changing peoples’ behaviour. However, we are trying to reduce emissions against a backdrop of a generally growing economy (over the long term), leading to a growth in traffic by all modes. At the same time, average car engine sizes continue to grow. Although they are now starting to stabilise, whether this is due to the recession or changes in peoples’ behaviour it is too early to say.

The use of biofuels is still promulgated as part of the solution but there is a growing realisation that its role will be limited. Biofuels as a by-product of used cooking oil and the like is fine, growing crops for biofuels is increasingly being challenged as a sub-optimal use of scarce agricultural land.

This implies that in the long term road vehicles will be predominantly dependent on electricity (either battery powered or using a fuel that is created using electricity, eg Hydrogen). If all cars were to be powered (directly or indirectly) by electricity running the same total mileage as now it would require the equivalent of around eight nuclear power stations operating flat out. In reality, off-peak generating capacity would be used, as off-peak demand is roughly half peak demand during the eight night time hours, enough power could be provided by using the off-peak capacity of 24 nuclear power stations or equivalent.

On top of this would be the electricity generation required for other all road vehicles, probably another 50% on top of that required by cars. The impact of extending electrification on the rail network in comparison would require at most the equivalent of half a nuclear power station. Even allowing for the fact that some of these numbers are “back of the fag packet” estimates it is still the case that a business as usual approach on the road network would require a substantial increase in electricity generation from renewable or nuclear sources at the same time as the country needs to be moving away from gas to electricity for both domestic and industrial use.

Can this massive switch to clean electricity be achieved? I don’t know but what is needed is more of a public debate as to what the consequences of a wholesale switch from oil to non-oil forms of propulsion for road traffic is. Can the UK provide the alternative sources of energy and if not it needs to start planning now for a less passenger transport intensive world.

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