The Van Trump Report

New Methods of Producing Green Hydrogen From Seawater Could Provide a Nearly Unlimited Energy Supply

“Green hydrogen” is considered a climate-friendly fuel source that many believe could power the future. However, a main stumbling block to adopting the clean fuel on a mass scale is the strain it would put on already dwindling freshwater supplies. Now, several research teams are reporting progress in utilizing seawater to produce hydrogen, which some say could provide the world an unlimited supply of clean energy.

Hydrogen is the most abundant chemical element on our planet but it is always partnered with other elements or compounds in nature. Water is of course the combination of hydrogen and oxygen. The most common technique used to separate the two is “electrolysis,” which uses an electrical current to split water molecules.

Using electrolysis requires vast amounts of water, though – producing just 1 gallon of hydrogen requires nearly 38 gallons of water. Scientists estimate that using water-sourced green hydrogen to fuel trucks and key industries would require close to 2 billion acre-feet of fresh water every year, which is enough to supply the combined populations of Canada and Australia.

Only about 3% of the earth’s water is fresh, and 2.5% of that is unavailable, locked up in glaciers, polar icecaps, the atmosphere, soil, etc. The remaining 97% of water on the planet is seawater. Theoretically, tapping the oceans to produce hydrogen could provide a nearly limitless supply.

Splitting hydrogen from seawater poses its own set of hurdles, however. One of the most problematic is the chlorine gas it produces. Chlorine gas is highly corrosive and typically destroys the electrolyzer equipment within hours. It also leaves behind untenable amounts of chlorine that could damage the environment.

Three separate groups of researchers now say they’ve figured out ways to split hydrogen from seawater while eliminating the undesirable chlorine effects. One group at the Royal Melbourne Institute of Technology (RMIT) in Australia have developed a catalyst to work specifically with seawater. Their solution involves coating the electrodes with negatively charged compounds and phosphates that they say repels negatively charged chlorine ions, thus preventing chlorine gas formation.

Another Australian group at the University of Adelaide are using membranes that allow only freshwater vapor to reach the electrodes. Lead researcher Zongping Shao, a chemical engineer, equates it to an internal distillation process and says their membranes resemble those already used in commercial desalination plants. Some scientists believe this would allow the incorporation of green hydrogen production with desalination projects, creating both a green fuel and fresh water.

At China’s Nanjing University of Technology, researchers are also using a membrane to prevent anything but freshwater vapor from entering the electrolyzer. A prototype in China’s Shenzhen Bay allegedly ran for over 133 days without any deterioration while producing over 250,000 gallons of hydrogen.

All of these projects require further testing to prove they are workable at scale, and more time still to build out commercial facilities. But if the hype matches reality, researchers think it’s possible that the world could be mass-producing green hydrogen within the next decade. (Sources: Science, Financial Times, Innovation News) 

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