A techno-economic-environmental analysis of the methanol production from biogas and power-to-X

Methanol is a key ingredient for the chemical industry and for the energy sector. Towards a transition into carbon-neutral future, it would be of great interest to reduce the fossil carbon footprint of the methanol synthesis by investigating alternative routes. A potential way to produce methanol in a sustainable manner is to utilize biogas, which is a carbon-neutral feedstock. However, it is challenging to provide sufficient biogas to large-scale plants. For this reason, we investigate in this paper the possibility of producing methanol in small-scale decentralised plants. We analysed the techno-economic-environmental performance of the downscaling of the standard methanol production via steam reforming and we compared it with the novel synthesis via direct CO2 hydrogenation with green H2. We observed that, with cheap electricity and high methanol value, these processes are both profitable, with a slight advantage for the steam-reforming route. However, the direct CO2 hydrogenation route can be improved by developing tailor-made less costly equipment, thus showing a potential for application in an energy storage context (i.e. with extremely cheap electricity). We also observed that the use of biomethane as feedstock for centralized methanol production shows a similar performance as the localized methanol synthesis, due to the high cost of the raw material. Therefore, we can conclude that, with every technology analysed, the shift towards a biogas-based methanol manufacture results in a more expensive product and that small-scale localized production may play a role in the bio-based methanol supply.