By swapping plastic parts for biobased alternatives, EVs could achieve lower carbon life-cycles.
Lemon, almond, and pomegranates could well form the beginnings of a moreish dessert recipe but in the hands of the BARBARA project, an EU-private sector partnership, they became chemical ingredients for a biobased car dashboard.
The BABARA project ran from 2017 to 2020 investigating how agro-food residues could be formed into fibre reinforced thermoset materials: a type of industrial material used by the aerospace, automotive, medical, energy, and sports industries.
Turning plant waste into industrial materials
Today, fibre reinforced thermoset composites, used in cars as bumpers, body panels, suspension parts, and brakes, are overwhelmingly made from fossil plastic. The benefits of plastics in such applications are numerous: manufacturers value its strength, light weight, moldability, and corrosion resistance.
A world without fossil plastics can sometimes seem unimaginable. This applies especially in the field of industrial applications, where strength and low weight really matter.
Yet as research into bio-based materials deepens, we are increasingly finding that compounds from plants and the mineral body parts of animals can offer properties needed to withstand heavy, repeated use, particularly after they go through some chemical and mechanical processing.
Fibre reinforced thermoset composites are just the kind of high-performance material many might believe have no organic substitutes. However, the BARBARA project showed how new configurations of plant-based materials could offer more sustainable alternatives for the automotive sector.
The 3-D printed dashboard prototype demonstrated by the BARBARA project is made mostly from a corn starch residue-based bio-polymer. This corn-based biopolymer base was blended with chemicals extracted from horticultural waste like pomegranate, lemon pigment, pomegranate biomordants, lemon fragrance and almond shell. The organic additives allowed the team to alter the properties of the base corn polymer, such as colour and strength, without resorting to synthetic chemicals.
By the end of the project, the BARBARA team had produced eight new materials that used corn biopolymer modified with natural additives from organic waste. Some of these additives worked as dyes, others as antimicrobial agents. Apart from the dashboard, the project demonstrated other functional prototypes, including car door handles and structures used in the building sector.
There is a lot of agro-waste around with potentially interesting physical properties but are currently going to waste: 75 % of almond shells are discarded by the agro-processing industry right now or used as biomass for energy generation. The BARBARA project has demonstrated there may be higher value, high-demand uses for these byproducts.
Bio-based car interiors
A similar EU research project called BIOMOTIVE ran at the same time as the BARBARA project. It was a far more expensive undertaking, with the total cost running into over €15 m compared to €2 million for BARBARA.
Here, the objective was slightly different: to produce plastic bio-based polyurethanes and fibres for EVs using materials that were 60-80% biobased. These materials are used in car interiors, door handles, seat foams and seat covering.
Polyurethane is a polymer often used as the base material in fibre reinforced composite materials, the focus of the BARBARA project. However, it also goes into car seat foam and BIOMOTIVE’s researchers developed an 80% bio-based polyurethane made from organic waste for just this purpose. They started off with waste wheat straw and beech wood, from which fructose and sucrose were extracted to form foundational input chemicals for the bio-polyurethane.
As for seat cover textiles, the researchers collected wood from a Finnish company to produce bio-based fibres that could be formed into yarn and fabric. Compared to ordinary fossil-based textiles made from polyester fibres, their assessment found that the pulp-based material represented a 92% reduction in its global warming potential.
BIOMOTIVE did not aim for 100% renewable materials in its prototype. The typical research priority in bio-based industrial materials is how to get the percentage of petroleum contained within them down. Because automotive and industrial uses demand strength and durability over long use periods, there is less emphasis on fully renewable and biodegradable content as there is in the food packaging sector, where single use applications dominate.
EV emissions
The BARBARA and BIOMOTIVE projects represent the very earliest stages of a bio-based car parts industry. This is beginning just as the auto industry is undergoing a seachange. Electric vehicles sales are slowly beginning to overtake combustibles on the global market, with all major car companies building electric models into their future growth strategies.
While EVs represent a marked improvement from a sustainability perspective on combustibles, there is still a need to get their emissions intensities down.
The majority of emissions from conventional automobiles are from the fuels needed to run them. EVs offer lower lifecycle carbon emissions than combustion cars just by virtue of the fact that they ever need a drop of fossil fuel to run.
Yet the environmental impacts of a car are not limited to their running fuel and understanding the carbon intensity of an EV requires looking at the life-cycle emissions released from building them.
These include the energy that fuelled the manufacturing process as well as the emissions released in extracting and processing raw materials. Manufacturing emissions are generally the second biggest contributor to the life cycle emissions of an EV, covering outer metals and the plastic fittings as well as the battery components.
Extracting and processing metals for EV batteries are particularly carbon intensive. By destroying biodiverse habitats and weakening the carbon-storage potential of the landscape, battery metal mining can bump up the carbon costs of electric vehicles. The emission impacts of EV manufacturing rise further when it takes place in countries with limited renewable energy roll-out and factories are drawing on fossil energy.
Because of all the carbon locked up in the manufacturing stages, the Tesla Model 3 still has emissions of 12.7 tonnes CO2e. This figure, however, assumes the car is using batteries manufactured in the US. The number rises to 19.5 tonnes carbon when batteries are manufactured in Asia. Since the Asian battery manufacturing industry is magnitudes bigger than the one in the US, the carbon count for an average car on the road is far more likely to be closer to the 20 tonne mark than 10.
EVs also generally use the same fossil plastics for its interiors and components as traditional cars for a good reason. A heavier vehicle has greater energy requirements and plastics offer that irresistible combination of strength, durability, easy workability, low weight and, crucially, cheapness that few if any materials currently offer.
Some even point out that EVs are a godsend for the plastics industry for this reason. Plastics are a much lighter industrial material than traditional ones like steel and aluminium and in this limited sense can contribute to a more energy-efficient car. Getting vehicle weight down is a big consideration in EV design since the battery in these makes them heavier than traditional cars.
For all these reasons, one report estimates that the plastics for EVs market is set to grow 19.7% during 2020 and 2027, tracking the huge boom in EVs expected over that decade.
It is important therefore that bio-biased industries turn their minds and resources towards the problem of reducing manufacturing emissions in EVs.
Weaning EVs off plastics
While EVs mark a step in the right direction for the transport sector, there remains room for improvement for making this technology as emissions-light as possible.
This is important as absolute demand for personal vehicles is expected to rise dramatically over the coming decades. Where possible, emissions from the manufacturing stage should be cut and the ambition should be to achieve as close to a zero emissions car model as possible, without the need for resorting to offsetting.
By offering strong alternatives that perform on weight, mouldability, and weight, bio-based producers could close off a potentially huge growth market for the petrochemicals plastic sector in coming years.
If they can offer serious substitutes for petrochemicals, bio-based producers could leverage the sustainability ambitions of the EV industry to get their materials into cars and displace oil plastics. This is no easy task since plastics make up between 11-20% of the weight of cars and no scaled alternatives to petrochemical versions for the automotive sector have been developed yet.
Yet demand for bio-based car parts will likely increase as the industry in EV grows and its claims of offering sustainable consumption come under closer scrutiny. There is already rising interest in this, most promisingly from public procurers, who are entities capable of adding high-volume demand in a short period of time.
Researchers from BIOMOTIVE reported requests from customers among ambulance manufacturers looking for vehicle components that could easily be recycled. One client involved in tendering vehicles for transporting patients specifically enquired about the availability of seats made up of bio components, which the researchers said could indicate a future market trend.
