The following figure is from the Government produced ‘UK greenhouse gas (GHG) emissions national statistics 1990 – 2017’. The bar chart shows the main sectors contributing to GHG emissions.
As is clearly seen the largest UK contributor to GHG emissions is transport. It is therefore self evident that decarbonising transport will be key to meeting the UK’s net zero target.
Decarbonising transport got me thinking about driving in the United States in the early 1990s where a speed restriction of 55 mph was enforced. The US had introduced the National Maximum Speed Law that prohibited speed limits higher than 55 mph. It was drafted in response to oil price spikes and supply disruptions during the 1973 oil crisis and remained the law until 1995. Why 55 mph? – it is where vehicles achieve optimal fuel efficiency. The law was enforced to reduce US reliance on oil imports; it was not related to the Climate Emergency.
Whilst the law was unpopular it did result in a reduction in fuel consumption. It should be recognised that a reduction in transport fuel demand will also result in less energy required by oil refineries which, as a consequence of their high energy use, are a significant source of greenhouse gases. Hence, speed limit enforcement is a double win.
Should we adopt such a law in the UK? It costs nothing by way of investment, would have an immediate impact on the UK’s carbon footprint and would save consumers on their forecourt bills.
Like the public reaction in the US, it is likely to be very unpopular, but one could argue tough, we all have to shoulder some inconvenience and take responsibility for delivering net zero.
How could we use the reduced speed limit to further contribute to decarbonisation? That could be facilitated by allowing electric and hydrogen powered vehicles, using energy from renewable sources, to travel at existing speed limits.
To my mind that would provide a very real incentive for many road users to transition from fossil fuel based transport to low carbon options of hydrogen and battery. A transition we know is essential.
It could be a case of less speed, more haste to the energy transition.
Tom Baxter is visiting professor of chemical engineering at Strathclyde University and a retired technical director at Genesis Oil and Gas Consultants
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