Consumers ‘misled’ on green benefits of lightweight car engines

EU Euro Standards encourage the automotive industry to use low-density materials such as aluminium in manufacturing to make conventional vehicles more fuel-efficient and reduce on-the-road emissions. But researchers at Cranfield University claim that the environmental cost of aluminium engine production far outweighs the carbon savings achieved through reduce tailpipe emissions.

“Current legislation takes such a narrow view of what makes a car environmentally-friendly that it has caused more damage than good,” said research lead Professor Mark Jolly, head of sustainable manufacturing at Cranfield University.

A cradle-to-grave study found that the production of each aluminium cylinder block consumes up to 3.7 times more energy than the production of cast iron. This increase occurs when the blocks are produced by sand casting. Cranfield estimates that the production of aluminium generates more than 10kgCO2/kg aluminium, negating the savings made from on-the-road emissions.

Jolly added: “It’s critical that governments and consumers start to look at the whole life cycle involved in manufacturing vehicles, not one indicator, with more holistic policies that actually reduce CO2 emissions rather than just presenting the image of doing so.”

Energy rating labels

The average life expectancy of motor vehicles is 210,000km. The Cranfield study found that a typical aluminium engined car would need to be driven for between 185,000km and 560,000km before any emission reductions were made from lower fuel use.

Cranfield, which estimates 70% of global aluminium production to be based on fossil fuels, has said that consumers have been misinformed about the sustainability of lightweight engines. The university insists that an energy rating system would provide consumers with a more accurate indication of their vehicle impact.  

“An energy rating label for all cars, taking into account the full environmental costs, would provide more transparency,” Jolly said. “Consumers who thought they were making a more sustainable choice have often been misled, and this needs to change.”

Driving change

Exhaust fumes from diesel and petrol engines are one of the largest sources of particulates emissions, the largest single contributor to the estimated 600,000 premature deaths across Europe from pollution-related heart and lung diseases each year.

Governments and businesses are now turning attentions to the emerging electric vehicle (EV) market. New analysis from Bloomberg New Energy Finance (BNEF) has found that EVs will account for more than half of new global car sales by 2040. This research came in the same week as France announced an outright ban on the sales of petrol and diesel cars, set to come into force by the same date.

The BNEF predictions are based on future reductions in price for lithium-ion batteries and varying cost components in EVs and internal combustion engine vehicles. The data also factors numerous commitments from automakers to introduce EVs into portfolios. Most recently, Volvo pledged to introduce an all-electric portfolio by 2019.

George Ogleby