Decarbonisation Technology May 2022 Issue

methane production. Waste-to-fuels processes are very topical and attracting significant investment from the oil and gas sector. Waste-to-fuels and waste-to-plastics The World Bank reports that 32% of waste in high-income countries is food and green waste, while 51% could be recycled (plastic, paper, cardboard, metal, and glass). In middle- and low- income countries, the total waste is less, and the amount of food and green waste increases to 53% and 57%, respectively (World Bank, 2022). The hydrocarbon-rich fractions (biowaste) can be separated from MSW and used as a feedstock for renewable fuels using processes for waste-to-fuels. In its Gela biorefinery, ENI has operated a pilot plant that uses a hydrothermal liquefaction process to produce a bio-oil that can be used as a low-sulphur marine fuel or refined further to kerosene and diesel (ENI, 2022). An alternative technology is using high- temperature gasification of biowaste to produce syngas, which is then converted using the Fischer-Tropsch (FT) process to longer chain hydrocarbons in the kerosene or diesel range (Rispoli, 2019). A number of investments in waste-to-fuels projects have been announced, with companies such as BP, Cosmo Oil, ENI, ExxonMobil, Neste, Repsol, and Shell in the first wave. Whilst the investments are primarily for the production of sustainable aviation fuel (SAF), they avoid biowaste going to landfill, which consequentially will avoid methane emissions. The Sierra

• Avoidance of up to nearly 1 billion tonnes globally of biowaste going to landfill with a concomitant reduction in methane • The use of biowaste as feedstock for renewable fuels avoids new releases of CO 2 from the equivalent amount of fossil oil • Reducing the amount of waste going to landfill would also lower the cost to society involved in managing landfill. Waste management takes up a significant part of local government budgets. Non-recyclable plastic waste is another component that can be separated from MSW to reduce the amount of landfill or incineration. OMV, in its Schwechat refinery, recently announced an investment to scale up its ReOil process (based on pyrolysis), in which plastic waste is converted to synthetic crude oil, primarily used for plastics production (OMV, 2021). While this does not directly contribute to methane reductions, it does reduce demand for crude oil and is a positive step towards a circular Bioenergy methane economy. The choice to invest in anaerobic digestion or waste-to-fuels, waste-to-plastics will be driven by local and regional considerations, such as the proximity of an integrated petrochemicals refinery with existing plant and expertise in fuels and plastics production. Partnerships between oil and gas companies, local authorities, and private waste management services will be important in the organisation of waste collection with separation of waste streams, preferably at source.

biofuels plant, a partnership between Fulcrum BioEnergy and BP, is located adjacent to one of the largest landfills in the Western USA (BP, 2018). The biomass fraction of mixed municipal waste, biowaste from private households, industrial waste, and used cooking oil are all listed as feedstocks for advanced biofuels in Annex IX of the EU’s Renewable Energy Directive RED II (European Commission, 2018). The benefits of waste-to-fuels are significant:

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Figure 5 Projected waste generation by region (million tonnes/ year) Source: (World Bank, 2022)