Sustainable cars: Looking beyond the tailpipe…

Following a plethora of ultra-low emission vehicle announcements from governments and industry, electric cars are beginning to be adopted by the public and will one day become commonplace. But, as Lucinda Dann investigates, a car's green credentials don't just lie in its exhaust emissions.

A global report released earlier this week detailed the anticipated massive growth of the ULEV market, with industry sales set to hit $36.8bn by 2019 – an 8.5% year-on-year increase, resulting in a global market worth $109.8bn. This increase would cause spending on petrol and diesel to fall by an estimated 40% in Britain by 2030, reducing the national fuel bill by £13bn to £20bn.

Ninety-eight per cent of a vehicle’s carbon footprint comes from its exhaust emissions. It therefore stands to reason that policymakers and carmakers are focusing their attentions on reducing these emissions with ‘green’ vehicles; electric cars and hybrids that are capable of reducing those exhaust emissions to zero.

But there is more to a ‘sustainable’ car than reduced fuel consumption or zero exhaust emissions. Cars are exclusively made of materials that have to be actively disposed of, such as metals and plastic. There is also the contribution of the complicated manufacturing process. With all of these materials, even electric cars are still a far cry from being truly ‘sustainable’. So what else are carmakers doing to produce more sustainable vehicles?


Under the bonnet

The car battery is a poster child for the closed-loop lifecycle theory, being the single most recycled product in the United States. In acid car batteries, 98% of all of the battery lead is recycled to be used again, meaning each typical new lead-acid battery contains 60-80% recycled lead and plastic.

The battery case for a Chevrolet Volt is covered in a composite that does a brilliant job at protecting the case during transit in the manufacturing process. Unfortunately, it is also difficult to recycle. Instead, manufacturer General Motors (GM) has repurposed the cases, converting them into bird and bat houses.

These houses have become a lynchpin within GM’s wildlife habitats program as they have helped to provide nesting spaces for bats, wood ducks, owls and bluebirds. This initative is also playing a crucial role in saving a rare Russian duck species.


Body design

The Smart car is renowned for its size, but probably less so for being green. In fact, 85% of a Smart car is recyclable. The outer skin of the car is constructed in modules for easy dismantling, made of scratch-resistant plastic and is 100% recyclable. Harmful substances like lead, chromium, mercury and cadmium are barred from the production process.

Windscreens are another car part that can be fully recycled. The vast majority of replaced windscreens have been ending up in landfill, but that is starting to change. 

As demonstrated in the below video, US windscreen recycling firm Auto Windscreens has come up with a method to recycle 100% of a car windscreen. The company’s health and safety manager Vanessa Jones explains: “It is truly amazing to think all that unwanted glass has been used to help make millions of bottles. I like the thought that I could be drinking from a bottle that is made partly of a windscreen once belonging to perhaps a Porsche 911 or a Lamborghini Gallardo.”



The green credentials of a Smart car extend to its exterior, too. It is powder-coated – a type of finish that is applied as a free-flowing, dry powder and does not require a solvent. This is generally regarded as the most environmentally-friendly painting method in the automotive industry, using 40% less energy than conventional painting methods with zero solvent emissions. Nearly 100% of the surplus powder is reused for painting and no water is consumed or wasted.

BMW Group is currently operating an ingenious electro-coating facility of its own at its manufacturing plant in Swindon. A 12-stage electrically-charged bath system is able to apply precisely the right thickness of paint to each area of the car body. This yields savings in both materials and energy. A programme to carefully control the level of humidity in the paintshop – a certain level of humidity is essential to the painting process – has also yielded a saving of 420 tonnes of CO2 annually.




In the States, Ford is manufacturing plastic car parts such as cylinder head covers for its popular models, using plastic extracted from old carpets. US firm EcoLon harvested the plastic resins from four million pounds of old carpets in 2010. Impressive as these schemes are, less than 10% of car interior carpets are recycled, so there is still work to be done.

In 2010, GM managed to divert 100,000 pounds of plastic waste from landfill by recycling the oil-soaked plastic booms used to coral the oil leak in the Gulf of Mexico. The waste was instead turned into plastic resin and then blended with recycled tyres from GM’s test tracks and other plastics and polymers. The resulting product is molded into baffles that deflect air around the vehicles radiator.



Being made of rubber, tyres are not inherently environmentally-friendly products. However, environmental savings can be made while they are still in use. Major tyre manufacturer Michelin says British motorists could be emitting more than two billion tonnes of CO2 into the atmosphere because they are not inflating their tyres correctly.

Some tyre manufacturers are looking to find other sources of natural rubber. Bridgestone is testing the viability of a perennial shrub called guayule to replace petroleum based synthetics. Fellow manufacturer Goodyear is experimenting with soybean oil, which the company says could actually increase tread life by 10%.

More than 48 million tyres are disposed of each year in the UK. However, the EU Landfill Directive banned tyres from going to landfill from July 2003. In countries without strict sanctions, such as China, tyres are burnt for fuel, causing emissions of sulphur dioxide to rise tenfold and emissions of dust particles to increase by almost 500%.

Instead, there are many uses for the recycled rubber such as in rubberised asphalt, railroad ties, playground surfaces, and shoes. Yes, shoes – late last year, global outdoor-wear company Timberland and tyre manufacturer and distributor Omni United teamed up to produce a line of tyres intended to be recycled into footwear out-soles once finished with on the road.

Lucinda Dann

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie