Unlocking low-carbon hydrogen transportation through a cost-effective hybrid CO2/heat looping strategy

Despite its crucial role in renewable energy networks, hydrogen transportation incurs elevated costs and high carbon intensity (CI). To enable affordable low-carbon hydrogen, this study examined integrating a closed CO2 and heat cycle via a dual solid carriers looping strategy to mitigate direct and indirect carbon emissions. A techno-environmental-economic analysis of the hydrogen transportation infrastructure was conducted on a large-scale overseas supply chain. This analysis involved base cases (i.e., LH2, LNH3, MeOH, formic acid, and dimethyl ether) and various combinations of hydrogen and CO2/heat dual carriers (i.e., CaO, ZnO, Li2O, and MgO). The results showed a considerable decrease in cost and carbon emissions through the integration of the CO2/heat closed cycle system. Particularly, the MeOH-ZnO route showed substantial improvement, achieving a CI reduction to 15.54 kgCO2-eq/kgH2 (i.e., 46 % lower than that of the MeOH route), with a cost of 6.0 USD/kgH2. In the projected 2050 scenario, employing the CO2/heat looping system further reduced CI to as low as 0.7 kgCO2-eq/kgH2 and a cost of up to 4.6 USD/kgH2, despite the use of costly renewable heat and direct air carbon capture. Integrating the CO2/heat looping system thus facilitates affordable, greener hydrogen transport, crucial for a sustainable energy economy.