From Birdcage Walk - reducing greenhouse gases

Latest update from IMechE HQ. Steve Sapsford examines the future use of alternative fuels and propulsion technology

Dear Member,

On 28 January 2020, the IMechE launched its report on decarbonising road transport, entitled “Accelerating road transport decarbonisation: a complementary approach using sustainable and low carbon fuels”. The report was aimed at highlighting that we cannot rely on electric vehicles alone to solve our climate change challenges and a more holistic approach was required.  It was, therefore, somewhat ironic that exactly one week later Boris Johnson announced that the ban on the sale of vehicles that use an internal combustion engines as the sole source of propulsion would be brought forward from 2040 to 2035 (hopefully earlier still) and would now include hybrid vehicles. 

The Institution of Mechanical Engineers wholeheartedly supports a complete shift away from fossil fuel use in any part of our energy system and we must find solutions in the near term that can make the biggest and fastest reductions in our CO₂ emissions.

The latest announcement suggests that there is “one-size-fits all” solution and that is electric.  However, we are running the risk of assuming that all a vehicle’s greenhouse gas (GHG) emissions are emitted at point of use. Whilst that might be where legislation has its current focus, we need to take a more holistic approach including the GHGs associated with vehicle production, day-to-day use and disposal/recycling i.e. full life-cycle analysis.

In our report, we demonstrate that all forms of propulsion technology, including renewable fuels, electricity and hydrogen could have a substantial impact on reducing GHG emissions. Some, that are currently being ignored and side-lined by the announcement, could have a much larger impact in the short term.

There are over 300 million passenger cars in circulation on European roads and around 99% are powered by diesel or petrol.  Sales of electric vehicles, including plug-in hybrids, represented 2.5% of new passenger vehicle sales in Europe in 2018. This means that over 97% of new vehicles are still powered by diesel or petrol and, once a new car is sold, its average life span is approximately 12 years.

This demonstrates that we simply do not have time to wait for the increasing share of EVs to make a dent on the passenger car CO₂ footprint.  Indeed, as we accelerate the adoption of EVs, it is possible that we are accelerating the production of GHG emissions unless battery manufacture, which can represent a significant proportion of an electric vehicle’s lifetime GHG emissions, is using only renewable energy.

So, whilst we rightly continue to invest in electric vehicles, especially with respect to inner city air quality, we must also pursue and invest in renewable and low carbon fuels made from sustainable and net zero sources. These alternative fuels would be able to use the existing infrastructure, reducing consumer impact at the fuel pump and potentially avoiding the high costs associated with new infrastructure to support electric vehicle adoption at pace.

Consequently, the Institution of Mechanical Engineers believes that by insisting that there is only one solution, the Government announcement side lines a significant complementary opportunity to reduce GHG emission associated with road transport and we are working hard on your behalf to bring data and evidence to bear in this politically-charged environment.

Steve Sapsford

Chair of the Powertrain Systems and Fuels Group