Changes in feedstocks of rural anaerobic digestion plants: External drivers towards a circular bioeconomy

Abstract

Abstract The aim of this study is to better understand the recent changes in the feedstocks of anaerobic digestion plants, the driving forces behind these changes and consequent opportunities to strengthen closed-cycle energy production and promote the circular bioeconomy approaches. The study analyses Poland – a country with a highly diversified agrarian structures and with various levels of the development and focus of regional agricultural sectors which belong to the main sources of biosubstrates to be energetically processed in anaerobic digestion (AD) plants. Biowaste, including biowastes originating in agri-food production and in households, is indicated as one of the key sources for a more sustainable biogas generation. Our findings indicate and prove a gradual shift in the mix of substrates, including the growing role of energy processing of biowaste from households and municipalities. It was also ascertained that in the initial phase of the development of Polish biogas market in early 2010s, the AD substrates in most important position were agricultural raw materials (energy crops) and agricultural waste. On the other hand, during the course of time and due to developing legal requirements as well as financial and market conditions, the biowastes from the food industry and of municipal origin have gradually gained significance. An unintentional shift towards the energy processing of the more sustainable AD substrates in Poland is visible despite a rather low environmental awareness of AD operators.