Interest in hydrogen energy storage continues to grow, owing to the very large storage capacity that liquid organic hydrogen carrier (LOHC) technology offers, compared with other technologies.
Currently, most hydrogen is stored as a cryogenic liquid or is compressed under high pressure, which are expensive storage methods. However, LOHC technology allows for storing hydrogen at ambient conditions, which allows for a range of stationary power applications such as grid support and energy self-supply for off-grid applications, to be sustained.
The Hydrogen South Africa (HySA) Infrastructure Centre of Competence was established by the Department of Science and Technology and the North West University (NWU).
HySA director Dr Dmitri Bessarabov tells Engineering News that energy is stored in the form of hydrogen molecules that do not discharge the way batteries do, can be transported in various forms and do not require electrical grids for energy transport.
He notes that LOHC technology is used for cooling power stations in the US by gaseous and liquid hydrogen, nitrogen and carbon dioxide logistics solutions supplier United Hydrogen Group, adding that a demonstration project is under construction in Brunei to transport hydrogen to Japan.
Used not only as fuel for fuel cells or energy storage options, LOHC technology can also be used by State-owned power utility Eskom to cool its generators. “LOHC technology can, however, help Eskom meet many logistical and safety requirements when dealing with hydrogen,” adds Bessarabov.
A precommercial-scale hydrogenation system for the production of LOHC was commissioned jointly by HySA and nuclear power plants manufacturer Framatome at the Potchefstroom campus of NWU earlier this year. The purpose of the system is to demonstrate production on a relatively large-scale hydrogenated LOHC and have hydrogen dehydrogenated at various locations.
“The scale hydrogenation system is fully automated and can store 4 Nm3/hr of hydrogen in dibenzyltoluene,” he adds.
Further, the expansion of fuel cell vehicles is accelerating, and these vehicles could be converted to use LOHC technology. There is also growing interest for the refuelling of fuel cell-based ships and trains using LOHC technology.
Bessarabov concludes that NWU, together with the HySA centre, is also considering microgrid concepts, including the integration of solar technology and batteries.