Making Tyre Sustainable
By David Shaw
The international tyre industry has been discussing “green” tyres for over a decade now. Historically that has meant tyres with low rolling resistance, often using a silica-silane combination in the tread compound.
Following pressure from Western governments to reduce energy consumption, and pressure from car makers to improve the supply chain, the meaning of “green” tyres is changing to encompass a wider definition of sustainability.
Among corporate entities, a sustainable business means one in which the company can continue to reward its shareholders into the foreseeable future. This means ensuring profitability, minimising the uncontrolled risks and ensuring that the products and services offered by the company are in tune with customers and markets.
Another meaning within the concept of a sustainable tyre is the idea of minimising damage to the environment over the product life cycle.
Although consumer demand for sustainable tyres in India is today limited, any tyre company which hopes to supply tyres as original equipment to vehicle makers will have to think seriously about its sustainability credentials.
A “green tyre” is one which minimises the consumption of resources during its manufacture, distribution, use and final disposal, while maintaining high levels of performance and safety.
Although this definition can be expressed in a few words, the processes and technologies required to deliver such a product are complex. More significantly, materials, process and in-service conditions all interact. This means there is no single recipe for making a “green” tyre.
There are also different metrics which can be used to compare how green a tyre might be. These should take into account the overall lifetime of the product; the amount of energy consumed while running throughout that lifetime as well as the energy needed to create the tyre and, of course, final disposal.
All life cycle analyses of tyres show that the energy consumed during service is much greater than the energy consumed during manufacture, added to the energy consumed in making and preparing the raw materials.
According to a 2001 study by the European tyre makers’ federation (BLIC), the total greenhouse gas potential of a “green” passenger car tyre in size 195/65 R15 is around 244 kg CO2 per tyre.
This is made up of:
23.9 kg (9.8%) in material sourcing
7.0kg (2.9%) in manufacture
1.5kg (0.6% in logistics)
210.8kg (86.45) during the service life
0.7kg (0.3%) during disposal.
In a technical sense, therefore, the greatest contribution that the tyre industry can make to reducing its global carbon footprint is to improve the fuel economy of tyres.
For the last 20 years or more the tyre industry has been addressing this subject with considerable energy. Demonstrating the results of this effort, more recent studies show that the in-service phase contributes closer to 90% of the total greenhouse emissions. For truck tyres the figure usually comes out at around 95%.
As most of us know only too well, tyres wear out. This has a number of impacts for sustainability. First is highlighted by Nokian Tyres. Finland-based Nokian says the impact of tyre dust worn away from the tyre during its lifetime represents significant environmental damage.
** David Shaw is Head of Research at Tire Industry Research. This report is based on one chapter in the upcoming report, Sustainabilit in the tyre industry due for launch at the Tire Technology Expo event in February 2014. The report is sponsored by Versalis, one of the world’s leading suppliers of synthetic rubber and now a player in alternative sources of natural rubber. The report examines every aspect of tyre manufacture and performance from the perspective of sustainability. More information can be found at www.tiresustainability.com.
Full text in PTA December-January issue