How green is the road ahead for polyester?

Stepping towards sustainability

Based on analysis supported by the University of Cambridge, we believe that the answer lies in a phased approach. In the short term, recycling technology is proven and offers achievable environmental benefits. Long term, biomass promises potential advantages, but questions remain as to whether today’s technology is scalable and robust.

When Tesoro acquired Virent, a leading developer of biomass technology for the production of paraxylene, it was a clear signal that leading companies are starting to consider biomass as a strategic solution. Yet many unanswered questions remain. For example, there are concerns around allocating arable land to chemical production as opposed to food crops, and the environmental trade-offs between biomass crops from the use of fertilisers. And recent low crude prices have benefited the economics of conventionally sourced virgin polymer, pushing sustainability further down the agenda.

So where does sustainability fit within today’s polyester industry?

The PTA example

Terephthalic acid (PTA) is a major raw ingredient of polyester. Over the past two decades, PTA production has reduced its carbon footprint by some 40%.

Yet, efficiency gains are finite. PTA technology has improved, approaching the thermodynamic limit of performance.

Moreover, in addition to the PTA plants using newer technologies, assets built over 20 years ago are still operating today. This highlights the main problem with the typical industry-wide environmental studies: the data is aggregated and averaged across a wide range of facilities. This obscures the disparity in process yields, fuel sourcing, and energy efficiency between individual assets.

My analysis, the Environmental Impact Curve (EIC), aims to develop specific understanding on an asset-by-asset basis, supported by our supply/demand database and cost modelling. Think of the EIC like a cost curve, but instead of quantifying the cost, we look at an environmental impact. The EIC chart below shows the cradle-to-gate carbon footprint for the global PTA industry. The area under the curve represents the potential for improvement. The analysis is powerful because, for the first time, the worst offending assets are shown in context of the best producers.

This means producers can differentiate their business not only on the basis of cost, but also at an environmental level. From PTA consumers, this means they can establish genuinely sustainable supply chain sourcing strategies, selecting suppliers who can deliver low carbon polyester products. In launching PTAir, BP is leading this approach. It will be interesting to see how swiftly others will follow suit.