SUMMARY
Ever depleting fossil resources, growing fossil feedstock prices and global environmental impact associated with continuously rising greenhouse gas emissions have led to increased attention for biobased products as alternatives for the present fossil-based ones. It is therefore important for scientists and academics to provide knowledge and explore practical routes for the sustainable transition towards biobased alternatives. This research focuses on the replacement of fossil-based polyethylene (fossil-PE) by biobased PE (bio-PE) from Brazilian sugarcane and polylactic acid (PLA) from US corn. The report gives an outlook on such a shift towards a sustainable biobased economy. The aim of this research is to assess the characteristics of the biobased product supply chains which could provide in the demand for biobased polyethylene and polylactic acid for the Netherlands on environmental, social and economic aspects in order to contribute to the existing fundamental research on biobased products. This led to the main research question:
How sustainable are the supply chains for biobased polyethylene and polylactic acid, which could meet the current demand for fossil-based polyethylene in the Netherlands, and how does this compare to the supply chain of fossil-based polyethylene?
An analytical framework is developed along which the three dimensions of sustainability can be evaluated; environmental (greenhouse gas emissions, biodiversity and the local environment), social (competition for food, welfare and wellbeing) and economic sustainability (market price). The report focuses on the demand for bio-PE and PLA which could replace the current Dutch demand for PE of approximately 500 kiloton per year.
The report shows that on environmental sustainability, bio-PE outperforms fossil-PE and PLA. Life cycle greenhouse gas emissions are particularly low for bio-PE due to the extensive use of bagasse as energy supply. PLA associated greenhouse gas emissions are slightly less than the greenhouse gas emissions for fossil-PE. Depending on the type of land that is converted to biomass feedstock, greenhouse gas emissions can increase due to the release of carbon from decaying biomass and the loss of soil organic carbon. This effect can be significant if rainforest is converted either by direct or indirect land use change. Even so, considering the relatively small demand, enough land is available in Brazil for the production of the biobased products without endangering bio-diverse regions. The main impact of biobased products on the local environment is the imbalance of NPK nutrients and for fossil-based products on- and offshore oil spills.
The main concern with regard to the social sustainability was found in the exploitation of sugarcane and corn field workers. Case reports were found on slavery and exploitation, although no structural proof was found. For fossil-PE, decrease of the local welfare and wellbeing was found for several countries producing naphtha. Competition for food was considered as one of the main indicators. It is found that there is no competition for food if only the Dutch demand is considered, but a worldwide demand for multiple biobased products would inevitably lead to competition for food. This stresses the importance of alternative biomass sources that do not impact food supply, such as lignocelluloses.
Even though bio-PE shows more favourable results than fossil-PE, biobased products are still unsustainable due to the high market price with respect to the biobased product. With current feedstock prices, market prices for bio-PE and PLA are respectively 40% to 60% more expensive than fossil-PE. The price imbalance can be partially explained by the fact that the costs of environmental degradation are externalized for fossil-based products. Internalizing these externalities by for instance green VAT or carbon tax would level the playing field for biobased products. A reduced green vat of 6% for “green” products (19% for normal products) would reduce the difference to 25% and 40% for bio-PE and PLA respectively. Additionally implementing a carbon tax of 50 USD/t CO2 would reduce the difference even further to 15% and 35% for bio-PE and PLA respectively.
