Thermodynamic and Economic Evaluation of Hydrogen Transport Technologies

Due to its high gravimetric energy density, hydrogen is considered as an interesting energy carrying substance for a future energy system based on renewable resources. In this context, energy distribution and thereby efficient, cheap and secure transport of hydrogen is an important aspect.

Today, hydrogen transport is almost exclusively realized by compressed or liquefied gas. Transportation as compressed gas affords high pressures, generating a certain security risk while the amount of transported hydrogen is still low due to the low storage density. Liquefied gas can reach substantially higher storage densities and thereby capacities but suffers from large energy demands for liquefaction and boil off-losses during storage. Several alternative storage technologies came into the focus of research to overcome these limitations. In the context of hydrogen transport, especially carrier-based hydrogen storage technologies like metal hydrides or liquid organic hydrogen carriers (LOHCs) seem promising as these technologies enable a dense storage of hydrogen at ambient conditions.

In this contribution, a thermodynamic and economic evaluation of several hydrogen transport technologies is presented. The analysis commences with the determination of the energy demands for hydrogen conditioning (e.g. compression, liquefaction), the actual transport and the provision of hydrogen gas at the point of use (e.g. hydrogen liberation from carrier). For all technologies considered in the analysis the energy demand for the actual transport is comparatively low. The conditioning (for pressurized and liquefied gas) and provision step (for carrier-based transport) have a far higher energy demand. Options to reduce the energy demands are pointed out. The cost calculation includes investment, maintenance, staff, energy, and material costs and shows the potential advantage of chemical carrier technologies over the established transport technologies.