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In September 2020, the BPDA published a new report which demonstrates why the carbon footprint of concrete pipeline products is significantly lower than HDPE alternatives. In this blog, we explore one of the main findings of this report: The impact of HDPE resin origins. We explain why it is important to get the supply chain and raw materials’ sources right. We also explain why the carbon footprint of HDPE products in the UK is significantly higher than originally thought.

Raw materials’ sourcing: Findings from the Circular Ecology pipes carbon model

The current version of the ICE Database, published in November 2019, reports a carbon footprint for concrete pipes of around 146 kg CO 2 e/t. That carbon footprint is based on an independently verified and certified Environmental Product Declaration (EPD) for British concrete pipe manufacturers, published by certification scheme IBU in 2017. However, within that database, the generic carbon footprint for an HDPE pipe alternative (around 2,520 kg CO 2 e per tonne) is based on a study carried out over 15 years ago by European trade association ‘Plastics Europe’. That carbon footprint can also be found in most databases used by Water Companies in the UK. An update to that Plastics Europe report is expected soon.

BPDA has long argued that the European carbon footprint of HDPE pipes, which is entirely based on a European resin scenario manufactured 100km away from the pipe manufacturer, does not reflect the true emissions of that sector in the UK. The carbon footprint of that European HDPE resin is reported in the ICE Database as 1,930 kg CO2e/t (a more recent PlasticsEurope report suggests 1,800 kg CO 2 e/t). By working with Circular Ecology, and with the help of European market data from 2016/ 2017 and recent European Commission reports offering details on the origins HDPE resin imports, we developed an alternative scenario based on the likely sources of HDPE resin imported from outside Europe.

Assessing the impact of imported HDPE resin

The first step was to estimate the likely carbon footprint of HDPE resins based on countries of origin. A multi-scenario model developed by Circular Ecology helped us come up with the likely embodied carbon values for HDPE resin produced in a number of countries in Asia, North America and the Middle East. For example, it is estimated that resin from the Middle East was likely to have an embodied carbon of 2,180 kg CO 2 e/t. North American HDPE resin footprint was around 2,010 kg CO 2 e/t. The carbon footprint of East Asian HDPE resin was estimated to be around 2,200 kg CO 2 e/t. Based on Plastics-Europe numbers, the embodied carbon of an average European HDPE resin is 1,800 kg CO 2 e/t only.

We then looked for data on the likely sources of such resin in the UK. It is believed that the vast majority is imported from European hubs like Belgium’s Antwerp where a range of international and European plastic resin is handled prior to re-export to the UK and other destinations. We found one European market study from 2016 which offered a breakdown of sources of HDPE resin consumed in Europe, including imports from the Middle East, North America and Asia. That market study was significantly conservative compared to values published in 2020 by the European Commission which suggested that almost two thirds of HDPE resin imported to Europe is from the Middle East. We also added the carbon emissions associated with shipping the resin from central Europe and different ports in the Middle East (Saudi Arabia), Asia and the United States. This enabled us to develop two distinct footprints for pipes with European and International resin.

How the HDPE resin origins affect the carbon footprint

Figure 1 shows the differences between HDPE pipes made of European and International resin based on our study. We decided not to amalgamate the two values as the proportion of International resin used in the UK is unknown. Internationally sourced resin has been used in making plastic pipes in the UK in the past. There is also a suggestion that Middle Eastern HDPE resin makes a significant proportion of resin used and re-exported from the EU (Platts, 2016).bpdagraphic

Figure 1. Carbon footprint of DN2100 HDPE pipe based on a European and International resin mix.

The results clearly show that the carbon footprint of a plastic pipe would increase by 6-7% on average with an internationally sourced HDPE resin. That percentage is likely to be higher if the up-to-date figures from the European Commission were used. It is imperative that databases, such as the ICE Database, seek more representative data from the industry or clearly add information on the limitations of many of the sources used for such footprinting data.

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