Demand-Driven Biogas Production in Full-Scale by Model Predictive Feed Control

For future energy supply systems with high proportions of renewable energy sources biogas plants are a promising option. They have the potential to supply demand-driven electricity to compensate the divergence between energy demand and supply by uncontrolled sources like wind and solar power. So far biogas plants have been designed to produce a stable and constant energy output. The major aim of the presented investigation was to proof the general flexibility of the anaerobic processes under full scale conditions for an energy output according to the grid demand. A model predictive control (MPC) was developed to predict feeding sequences to fulfill a demand-driven utilization timetable and react effectively to alterations. Full-scale experiments showed a high flexibility in the gas production and high process resilience towards pulse feeding. Depending on the used substrates the necessary gas storage demand could be reduced by more than 60 % compared to the common constant feeding operation. The flexibilization of existing biogas plants can contribute substantially to balance demand and production within the future energy system.
Proceedings of the 25th European Biomass Conference and Exhibition, 12-15 June 2017, Stockholm, Sweden, pp. 1845-1851