
Prof Mark Jolly, head of the Sustainable Manufacturing Systems
Centre at Cranfield University, says that as the death knell sounds for diesel and petrol cars, we’re not getting the full story on the energy and environmental costs of their successors
Why don’t we have energy rating labels for our cars and other vehicles?
We think we already do — via the checks on tailpipe emissions and CO2 that are backed up by government legislation and the car manufacturers themselves, with the latter always looking for ways to reduce emissions via lower fuel consumption. So it’s all good.
Except this single measure, used around the world as an indicator of what constitutes
an environmentally friendly motor vehicle, is a snapshot. Just in itself, it’s misleading for consumers, governments and societies as a whole. Worse, it’s exactly this focus on tailpipe emissions that has the potential to drive up CO2 discharges, given that the number of cars worldwide is expected to double to two billion by 2035.

At Cranfield University’s Sustainable Manufacturing Systems Centre, we’ve looked at
what the push for lower tailpipe emissions has meant, such as more lightweight vehicles with aluminium engines. Less fuel is used and emissions are lower – but what about all the energy required to manufacture the lighter engines? It’s a disturbing picture of hidden environmental costs and damage.
The production of each aluminium cylinder block consumes 1.8 to 3.7 times more energy than the production of a block in cast iron. The nearly twofold increase in energy consumption occurs when the aluminium components are produced in reusable metal moulds, referred to as high-pressure die casting. The almost-fourfold energy increase results when the aluminium cylinder blocks are produced by sand casting; where the components are created in expendable sand moulds.
Overall, more than 70 per cent of global aluminium production is based on fossil fuels. Under these conditions, the energy-intensive production of aluminium generates more than 10kg of CO2
per kilogram of aluminium. That means a typical aluminium car would need to be driven for between 185,000km and 560,000km before there were any environmental benefits from the lower fuel use involved. The average life expectancy of motor vehicles is only 210,000km, so the majority of cars aren’t helping the environment – they’re just increasing CO2 emissions.
We also need to bear in mind the waste from the production of aluminium: what’s known as ‘red mud’. It has a pH value of 14 and is highly toxic. Two tonnes of red mud is created for every tonne of aluminium, and we already have great lakes of the stuff, which burns anything in its path.
These figures come from a detailed ‘cradle-to-grave’ study of the total energy and CO2 impact
of passenger vehicle engine production, based on interviews of more than 100 manufacturers and industry experts, from mining through to engine production and on-the-road use. The study focused on the most representative engine in use globally – a 1.6-litre four-cylinder engine – and compared aluminium models with the more traditional cast-iron engines with the same driving performance. The aluminium industry has argued that the highest energy consumption occurs during the production of ‘virgin’ aluminium from ore and that cylinder-block production primarily uses recycled aluminium. Our study took this into account, adopting the best-case scenario for aluminium via infinite recycling.
We have to start looking at the full energy costs and environmental implications of manufactured products such as cars, and energy rating labelling would be one way of helping consumers to get a more truthful indication of what’s green and what’s not. Aluminium is just one of the hidden costs. Electric cars are accepted as a sustainable transport option of the future — but what about the huge energy costs involved in manufacturing the batteries?
Taking into account the full life-cycle costs of manufacture and use, the best option appears to
be vehicles fuelled by natural bio-gases.
When they can, consumers want to make green choices. We rely on the ‘authorities’ – whether
that’s driven by industry or government – to give us accurate and balanced information. Without sharing data on the whole life cycle of manufactured products, we’re not getting that. We’re not even close.
Governments need to be guided by people that know and are aware….they need ministers that have scientific backgrounds that understand technical detail before making their choices on our behalf
What would reduce energy consumption even more is instead of replacing the complete vehicle they were made more readily repairable, especially if there was less need for special tools. That way the lifetime of the complete entity would be extended, merely replacing those parts which wear out or break.
please, mech eng, get us the choice of a reasonable speed and brakes, stainless-steel body, water-shedding subframe, wind-up windows and an engine one can work on, as you say, repairable!!!
Dear Nick,
I totally agree. Design for sustainability includes designing for repair, remanufacture, reuse and only finally recycling. Look at what Caterpillar are doing.
Sounds like we need a way to find some useful way to recycle red mud into something else.
http://cen.acs.org/articles/92/i8/Making-Red-Mud.html
If only we could – of the 120 million tonnes produced every year there is apparently a use for some 2000 tonnes p.a. I am led to believe that the Aluminium companies have been exercised by this issue for many years now and there has been a lot of research money spent but to no avail.
I apologise 2 million not 2 thousand tonnes have a use – but it’s still a drop in the ocean we have produced!
About 15% more CO2 is added to the manufacture of a BEV compared to a Gasoline Car for the manufacture of the battery, full report here answering your question about the small amount of energy required to manufacture the battery. BEV vehicles reduce CO2 and emissions compared to Gasoline cars, and the further they are driven the more reduction there is. Whereas the opposite is true for the Gasoline car.
http://www.ucsusa.org/sites/default/files/attach/2015/11/Cleaner-Cars-from-Cradle-to-Grave-full-report.pdf
In use yes, but the point is about lifetime ‘cost’ from manufacture through use and then scrapping. I’m not arguing against more environmentally sound engineering but the issue is much wider than usage. These wider paradigm issues need to be incorporated in the overall proposal. And repairing and replacing parts of the overall vehicle surely is better than scrapping the whole thing, which will be well before it has remotely ‘paid’ back the environmental cost of its manufacture and potential end of life disposal.
shame about this, lithium precious resource, bad battery life from non-use. Looks like diesel ok after all, except those smokey old buses
and the black smoke brigaden putting their foot down through ignorance
Yet there is also nothing made to replace asphalt/bituminous with durable, stiff concrete/cement road as in Belgium, Canada, Morocco, etc…[zero pothole maintenance] Electricfy the mopeds and scooters first because the gFuel/KW-h is much poorer: they do not have the R&D to make it better for mopeds and scooters. Then move to cars. Do NOT build a plastic canopy over the motorways: after Grenfell tower, what are try to do: Grenfell tunnel?
Ha ha-I loved the part ref “concrete roads and low maintenance costs thereof”…obviously never driven down the A12 from Ipswich to London……loosens your fillings, apart from the noise. How you long for nice smooth tarmac…….suddenly life becomes worth living again when you do
J.Fulcher
Hooray for finally getting around to looking at the environmental costs and nor is it difficult to look up the energy current account for moving people per km. Actually compared to the bicycle, cars aren’t even in the frame…..
Brilliant.
We need to get away from the current measurements encourage the disposable society.
A punter buys a car and is told it is good for the environment. Then they tell him it wasn’t really that good and start talking about scrappage to end it’s life prematurely, driving the next cycle of disposability and completely hiding the environmental disaster of built in obsolescence.
Could Prof. Jolly do an article to expand his thoughts regarding electric cars, battery manufacture and compare that with bio-gas powered cars please?
And deal with the child labour used in the foraging for Cobalt in Nigeria – another essential for Li batteries
Dear Rob, that is in hand and I hope to have the results by the middle of next year.
Not arguing against any of the above, but I thought one of the main drivers for reducing CO2 emissions from vehicles is to improve the air quality in conurbations.
It is, but the argument here is that that’s ill-considered and takes no account of the cradle-to-grave energy used nor CO2 produced. The Prof’s energy rating label is a good idea.
CO2 is not the problem of air quality in conurbations, or anywhere else;
SO, NOx, CO, oily particulates, soot are.
The air quality is destroyed by other gases and emissions such as NOx and particulates. The particulates don’t just come form the exhausts of cars more of it comes from the brakes and tyre wear!!! The CO2 is not a local thing but affects the global system whereas the particulates tend to affect the local system, as in the conurbations. I Don’t see electric vehicles significantly changing the particulate emissions if all they do is get designed the way current ICE powered cars are. To significantly reduce particulate we need less braking (maybe by using electromagnetic braking?) and less tyre wear – and I don’t see electric vehicles reducing that! Overall in terms of lifecycle I am still not convinced that the EV pays back the CO2 of manufacture over the current life time of a vehicle – if however we use vehicle for longer and got more use out of each individual vehicle (we only use our cars for ~7% of the time ) i.e. sharing our transport – then maybe they will help reduce the CO2 eventually – again with the proviso that the electricity that is used to recharge the batteries is all renewable and not fossil fuel produced – which currently is not the case in the UK or anywhere in the world except Iceland!
This is not a good conclusion! Where does ‘natural biogas’ come from? Ultimately agricultural land. So in a world full of starving people we used this land to drive our cars?
What’s needed is less driving.
What about Cyborg bacteria?
http://www.bbc.co.uk/news/science-environment-40975719
I support Tom’s view. This throwaway conclusion is unsupported and frankly wrong. The Committee on Climate Change here in the UK has produced a good report setting how limited bioenergy resource are. And in any case the lifecycle emissions for biogas are not great as set out by IPCC and more importantly as Tom notes the land needed will displace much more important agriculture!
Biogas can be produced using waste food, grass, wood and a whole variety of other feed stocks.
There was a similar argument used against biopolymers which are derived from cattle grade corn but it used a tiny proportion, much less than ends up getting wasted. Reducing & recycling waste materials should be a priority so that it doesn’t impact arable farm lands.
That I totally agree with. Not just drive less but consume less in general! But please don’t shoot the messenger all I stated that that was the result not that we should be building more cars. The solution is actually to have far fewer cars and a “sharing economy – i.e a transport system. To paraphrase the strap line from San Diego MTS which I have tweeted before “the sign of a developed economy is not where the poor can buy cars but where the wealthy use the public transportation system”.
mantra mcluhanisation manipulatively maximised in gettyimages.com’s “vintage blue car” speciously selected for its blue smoke-stroke cycle ceased since seventies when nox & soot were 3-4x higher, as statistician Speigelhalter stated in codswalloping claimed 40k.pa deaths due to “dirty diesel” cavalierly cavorted by campus careerists in pickpocketing poor old pursey public’s pumpishment, intoto £30Bpa! As for MJ’s “natural bio-gases” well what about (wikipedia.org) 30-50% co2 that supplements suphur scrubbing as pricey process overhead, never mind entropic exorbitance of supplying stuff for use anywhere other than on sourcing site such as by water utilities almost since inception, also in agriculture as soil supplements especially. Really is belief beggaring that society has been so scammed by educational ecomentalisation explosion since seventies at expense of economically efficacious cerebrally challenging content but then that’s also why it happened as I know having been sacked for sticking with tougher topics supposedly stressing students evermore expansively favoured as fees fodder because best of bunch once challenged clamoured my PhD projects despite ludicrously lucred lures of city spivvery and now those good guys are tree-topping in revenue generating constructive corporates.
As we scrap oil refining and fuel engines there will be a lot of engineers available but few new jobs. Hopefully we will build electric cars in the UK (if someone else pays of course). Unbelievable that the UK government would just announce a game-changing policy without wide discussion of the implications of it.
“Roost come home will the chickens to” and the naval acronym SNAFU come to mind.
The trouble with ICE engineers is they need massive retraining to work on EV.
If we are fed mis-information about the true energy cost of cars, think what we we are fed about the capacity of green power sources. A wind farm that can supply 20000 homes, etc. We all know that means 2000 on average and none on many days. This publication is as guilty as the rest. I for one am tired of it.