Green hydrogen is a fantastic, innovative power source. It uses renewable energy to produce hydrogen with a significantly lower carbon footprint than other hydrogen types. The problem? In addition to the high cost of production, green hydrogen uses a lot of water. How can we overcome this roadblock?

To understand why the process has a water issue, it is important to know how green hydrogen is produced. Obtaining hydrogen depends on a process called electrolysis, in which an electrical current is passed through water molecules. This current, powered by renewable energy when producing green hydrogen, splits the molecule, separating the hydrogen atoms from the oxygen atom. The hydrogen is then stored for later use as a source of energy. 

The process is efficient, and the only byproduct is water. However, a significant amount of water is wasted. To produce one kilogram of green hydrogen, approximately nine times that amount of water is required. Some experts predict that by 2050, annual green hydrogen demand will reach 500 metric tons, requiring 4.5 trillion liters of clean water for production. An estimated 4 billion people are currently experiencing water scarcity, and sustainable energy sources shouldn’t further exacerbate the problem. 

How do we solve this problem? Some experts believe the answer lies in utilizing seawater. Seawater is not a natural alternative to freshwater for human consumption—it requires intensive desalination treatment to make it drinkable. For electrolysis, using seawater would leave the freshwater drinking supply alone. 

Seawater is not a perfect solution. If it is not desalinated, the salt in the water is tough on equipment. A potential solution could emerge from a Chinese energy company called Sinopec. The company is working to engineer hardier electrolysis technology, explaining that seawater “contains approximately 3% salt, and impurities, such as chloride ions, can corrode electrolytic electrodes, while cation deposits may clog equipment channels, reducing efficiency and causing damage.” 

Skipping the desalination process would save time, money, and energy, and Sinopec’s technology appears to be a promising way to deal with seawater’s impact on equipment. The company launched a successful pilot project last year, located by the Yellow Sea, that paired renewable energy with direct seawater electrolysis. According to the company, that project is capable of producing 20 cubic meters of green hydrogen per hour. The company believes that the technology can also be applied to industrial wastewater, potentially opening up another avenue for reducing reliance on clean freshwater. 

Green hydrogen has the potential to power a sustainable future, but its water problem must be solved. Thankfully, the power of markets and innovation is undoubtedly sufficient to address issues like this in the coming years, whether the solution lies in using seawater or elsewhere. Will technology like Sinopec’s be enough to reduce freshwater consumption? Time will tell. 

The views and opinions expressed are those of the author’s and do not necessarily reflect the official policy or position of C3.