A team of Chinese researchers has moved a step closer in the quest for clean, renewable energy by converting seawater into hydrogen and oxygen.

The offshore platform development that harnessed both wind and solar power in the first successful attempt to use seawater without the need for desalination was led by researcher Xie Heping from Shenzhen University and the state-owned Dongfang Electric Corporation.

The platform – dubbed “Dongfu Number One” – is anchored in the waters of southeastern China off the coast of Fujian province and is capable of withstanding high waves and gusts up to force 8 on the Beaufort scale.

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“It successfully completed a 10-day continuous operation during its inaugural run in May, marking a promising start to the prospect of offshore hydrogen production powered by renewable energy,” state news agency Xinhua reported on June 3.

The 63 square metre (678 sq ft) platform combines a hydrogen production system with a stable offshore wind power supply system. By combining the two components, the researchers created an environmentally friendly floating farm that electrolyses seawater into hydrogen without creating undesirable side effects or pollution.

“This demonstration experiment not only validated the device’s anti-interference capacity but also produced valuable data. The project is an exemplary case of transitioning from academic achievement to industrialisation,” the report said.

https://www.hydrogeninsight.com/innovation/chinese-scientists-produce-green-hydrogen-directly-from-seawater-at-floating-offshore-pilot-project/2-1-1461905

Chinese state-owned wind turbine maker Dongfang Electric has successfully produced green hydrogen directly from seawater during ten days of testing on a floating offshore platform.

Electrolysers usually require purified water to ensure that the electrodes are not contaminated when splitting H2O into hydrogen and oxygen — and desalination equipment is usually factored into green H2 projects that need to source their water from the sea.

The floating platform — which includes in-situ electrolysis, as well as “intelligent energy conversion management”, safety detection and control systems — was said to have produced hydrogen in a “stable” fashion for more than 240 hours at the Xinghua Bay offshore wind farm, off Fujian province, despite enduring gale-force winds, one-metre high waves and a rainstorm, according to China’s English-language news channel CGTN.

While the new technology could remove the need for desalination, the removal of salt and other substances and microorganisms from seawater by reverse osmosis is relatively inexpensive, costing about 0.035kWh of electricity per kilogram of hydrogen — a fraction of the 50-65kWh/kgH2 needed by electrolysers, according to Paul Martin of the Hydrogen Science Coalition.

Nevertheless, the Chinese technology removes the need to build onshore desalination plants, and means that hydrogen could be produced directly offshore using power from nearby wind turbines, and then pumped to shore via pipeline, which could be a cheaper option than sending offshore wind power along subsea electricity cables and producing green H2 onshore.