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

TL;DR

This paper proposes an integrated Power-to-X hub at biogas plants for efficient renewable hydrogen and methanol production, optimizing costs and resource use within the EU's net zero strategy.

Contribution

It introduces a novel integrated PtX hub concept sourcing renewable CO2 from biogas plants, optimizing its operation and costs for scalable renewable fuel production.

Findings

Methanol costs could be below 650 euros per ton

Hydrogen production costs could be below 3 euros per kg

A local hydrogen grid improves operational flexibility

Abstract

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.