Agricultural anaerobic digestion plants: What LCA studies pointed out and what can be done to make them more environmentally sustainable

To better highlight how the choices on the feeding mix, the digestate storage, the surplus heat valorisation as well as the plant size can affect the environmental performances of agricultural AD plants four plants have been analysed in this study. The results suggest that the energy crops production and the operation of anaerobic digesters, including digestate emission from open tanks, are the main contributors to the impacts from biogas electricity. This entails that it is environmentally better to have smaller plants using slurry and waste rather than bigger plants fed with energy crops. Recovering heat waste as well as covering of digestate tank would improve significantly the environmental sustainability of biogas electricity, and particularly the global warming category.