Assessment of biogas production limits in anaerobic reactors for a flexible energy production

Due to the intermittent nature of solar and wind energies, on-demand biogas is a production way that could find its place in the future energy mix. It has been proven possible to modulate the biogas production without long-term consequences in literature. Experiments of punctual overloads have been conducted on three laboratory-scale reactors, with five different substrates. Each baseload production has been insured by three different substrates mixes, each with different kinetics. The effects of base organic loading rates (OLR), substrates kinetics and baseload substrates were assessed. Flexibility on reactors was defined as the margin between the maximal production and the baseload production. The maximal daily production was in the same order of magnitude on the three reactors with fast-degradable substrates (around 1 to 1.2 L CH4/L of reactor). Flexibility is optimized with a low baseload activity (coming from low OLR or slow-degrading substrates) and fast-degradable substrates used in overloads