Biogas Production from Steam-Exploded Miscanthus and Utilization of Biogas Energy and CO2 in Greenhouses

The costs of producing protected vegetables comprise up to 78 % of the total operating costs in greenhouses. These expenses mainly result from energy consumption. Increasing energy efficiency and expanding the use of renewable energy sources are essential for global competitiveness. The aim of this study is to optimize methane production from miscanthus and to evaluate the potential use of miscanthus as a source of electrical energy, heat, and CO2 in vegetable greenhouses. To optimize methane yield, miscanthus was pretreated by steam explosion using different time/temperature combinations. Pretreatment resulted in a more than threefold increase of methane yield from anaerobic digestion (374 lN kgVS−1) compared with untreated miscanthus. Based on technical parameters from two greenhouses (in Northern and Southern Europe), four different energy balances were established. The balances showed that using methane produced by pretreated miscanthus in vegetable greenhouses can enhance the entire process and therefore make it more sustainable.