A recent study – Systematic assessment for an integrated hydrogen approach towards the cross-regional application considering solar thermochemical and methanol carrier – offers a promising solution to the challenges of hydrogen production and long-distance transportation.
Published in Applied Energy, the report proposes an integrated hydrogen energy system that combines solar thermochemical technology with liquid organic hydrogen storage to address scalability and flexibility issues in the green hydrogen sector.
Integrated hydrogen energy system
The study introduces a solar biomass gasification-based hydrogen system that integrates methanol hydrogen storage with solar thermochemical dehydrogenation. This approach is designed to achieve efficient hydrogen production and utilisation – tailored specifically for cross-regional applications involving liquid fuel systems.
It leverages the strengths of solar and biomass resources. Solar thermal energy is harnessed to drive biomass gasification, which produces hydrogen-rich syngas. The high-temperature solar thermal energy used in the gasification process helps to generate this syngas, which is fed into a methanol synthesis reaction.
The unreacted syngas and the waste heat from methanol synthesis are used by a Brayton-Rankine combined cycle to generate power. At the point of hydrogen consumption, mid/low temperature solar thermochemical technology decomposes the methanol, a hydrogen carrier, to release the required hydrogen.
Efficiency and innovations
Under optimal operating conditions, the system achieves on-design energy and exergy efficiencies of 52,9% and 46,7% respectively. The study highlights the system’s ability to effectively harness solar and biomass energy, providing a promising method for using these abundant resources.
A key innovation of the system is its use of methanol as a hydrogen carrier. Methanol, with a hydrogen storage density of 12,5% and established commercial synthesis technology, facilitates the flexible and efficient transportation of hydrogen over long distances. It can be transported using conventional liquid fuel pipelines or tank trucks – adapting to existing infrastructure and reducing the need for new, costly storage and transport systems.
Environmental sustainability
The integrated hydrogen system also emphasises environmental sustainability. The study provides a detailed analysis of hydrogen and carbon element migration throughout the system, showcasing its efficient use of biomass and minimal carbon emissions. The study found 51,3% of the hydrogen is exported as gaseous hydrogen while only 21,4% of the carbon is ultimately released into the environment.
The study presents a robust solution for cross-regional hydrogen supply, combining solar and biomass energy with innovative methanol-based hydrogen storage to offer an efficient, scalable and environmentally sustainable approach.
