Mitsubishi Heavy Industries (MHI) has jointly developed a closed-cycle fuel cell system with the Japan Agency for Marine-Earth Science and Technology (JAMSTEC).
The fuel cell system is designed to power offshore vessels such as manned submersible ships and unmanned towing units, landers and ROVs.
Such equipment has become increasingly sophisticated over the years, with expanding experiment lengths and observation durations further putting a strain on current fuel cell capabilities.
According to MHI, "power requirements have grown to a level beyond the capacity of storage batteries having limited output capabilities," prompting the Japanese engine giant to develop alternative solutions.
Closed-cycle fuel cell systems have been under development for some time but have traditionally encountered significant hurdles, such as the need for gas circulation equipment and humidifiers preventing a compact physical footprint. MHI and JAMSTEC achieved a breakthrough in this regard, conceiving a new gas circulation system configuration that eliminates the need for the extra equipment.
Further, the system has also been made gas-tight, preventing minute leaks of hydrogen gas.
Known as a solid-polymer high efficiency multi-less fuel cell system (HEML), the system utilises a valve that switches between the upstream and downstream sides of the fuel cell stack. Further, its compact size reduces energy consumption and enables a faster startup time.
MHI and JAMSTEC subsequently put the new system under trial, installing it on board JAMSTEC's marine research towing unit 'Deep Tow'. Submerging 'Deep Tow' to a depth of 180 metres, the HEML was put to work, powering two observation units simultaneously.
According to MHI, the trial was successful: "The test operation confirmed that power was supplied stably and that the equipment receiving power from the system continued to perform their observation duties without interruption," said the company.
"The HEML has cleared earlier technical hurdles and is expected to supersede conventional storage batteries and fill a major role as an underwater power supply for marine research vessels and equipment over long periods of time. Now commercially viable, further development will proceed to achieve a market-ready fuel cell with outputs in several kilowatt classes."
