Optimizing hydrogen and e-methanol production through Power-to-X integration in biogas plants

The European Union strategy for net zero emissions relies on developing hydrogen and electro fuels infrastructure. These fuels will be crucial as energy carriers and balancing agents for renewable energy variability. Large scale production requires more renewable capacity, and various Power to X (PtX) concepts are emerging in renewable rich countries. However, sourcing renewable carbon to scale carbon based electro fuels is a significant challenge. This study explores a PtX hub that sources renewable CO2 from biogas plants, integrating renewable energy, hydrogen production, and methanol synthesis on site. This concept creates an internal market for energy and materials, interfacing with the external energy system. The size and operation of the PtX hub were optimized, considering integration with local energy systems and a potential hydrogen grid. The levelized costs of hydrogen and methanol were estimated for a 2030 start, considering new legislation on renewable fuels of non biological origin (RFNBOs). Our results show the PtX hub can rely mainly on on site renewable energy, selling excess electricity to the grid. A local hydrogen grid connection improves operations, and the behind the meter market lowers energy prices, buffering against market variability. We found methanol costs could be below 650 euros per ton and hydrogen production costs below 3 euros per kg, with standalone methanol plants costing 23 per cent more. The CO2 recovery to methanol production ratio is crucial, with over 90 per cent recovery requiring significant investment in CO2 and H2 storage. Overall, our findings support planning PtX infrastructures integrated with the agricultural sector as a cost effective way to access renewable carbon.