China has launched a revolutionary facility in the eastern province of Shandong that produces fresh water from seawater for just two yuan (US$0.28) per cubic metre, generating green hydrogen as a by-product in a breakthrough that could redefine global water and energy systems.
This small but world-first installation in the city of Rizhao is powered entirely by seawater and low-grade waste heat from nearby steel and petrochemical plants, official provincial news outlet Dazhong reported on Saturday.
The facility has operated continuously for over three weeks, producing high-purity hydrogen without the need for costly desalination or precious freshwater resources, the report said.
For every 800 tonnes of seawater processed annually, the system delivers 450 cubic metres (118,877 gallons) of ultra-pure fresh water ideal for industrial cooling or residential use.
It also delivers 192,000 standard cubic metres of green hydrogen and 350 tonnes of mineral-rich brine for marine chemical production – achieving a “one-in, three-out” circular economy.
The hydrogen, produced at the energy cost of 4.2 kilowatts of electricity per cubic metre, is enough to power 100 buses for 3,840km (2,386 miles) every year, according to the report.
The cost is remarkably low, even undercutting a seawater desalination technology powered by industrial waste heat in nearby Jinan city, which costs four yuan to produce a cubic metre of fresh water, according to a local media report from August.
For context, Beijing charges five yuan per cubic metre for residential tap water for the first 180 cubic metres in a year.
The Rizhao facility can produce fresh water more cheaply than water-scarce Middle Eastern countries with major desalination operations.
According to the Saudi Water Authority, which has the world’s biggest desalination capacity at 11 million cubic metres per day, Saudi Arabia and the United Arab Emirates have some of the world’s lowest desalination costs, with prices below US$0.50 per cubic metre.
Meanwhile, in the United States, the cost of desalinated water at the country’s largest seawater desalination facility, the Claude “Bud” Lewis Carlsbad Desalination Plant in California, was estimated at US$2.21 per cubic metre, according to a 2021 analysis by environmental economist Michael Hanemann of Arizona State University.
In China, the new facility feeds on seawater and heat generated by nearby steel and petrochemical industrial plants to produce high-purity green hydrogen energy.
“This is not just about producing a canister of hydrogen; it opens up a new path for ‘extracting energy from the sea’,” Qin Jiangguang, a senior engineer at the Laoshan Laboratory, a marine research centre in the large port city of Qingdao, told the Shandong news outlet.
Hydrogen is considered the ultimate non-polluting fuel and energy-storage medium. It is produced through electrolysis, a process where water is split into hydrogen and oxygen using electricity.
Conventional technologies require high-purity water, especially fresh water, as poor water quality can cause the process to fail.
For example, calcium and magnesium deposits in seawater can clog electrodes, while high concentrations of chloride ions can corrode electrolysis equipment and catalyst materials, according to Dazhong. But in northern coastal areas, freshwater resources are limited.
To use natural seawater directly, the Shandong facility uses corrosion-resistant catalysts and technologies to regulate seawater.
The facility also uses waste heat to produce high-quality fresh water, eliminating the need for traditional cooling units. This reduces equipment costs and energy use.
The new facility’s power utilisation rate is over 20 per cent higher than that of conventional freshwater electrolysis hydrogen production units.
Li Jiawei, an assistant researcher at the Laoshan Laboratory, said the facility “validates a new paradigm for zero-carbon hydrogen energy supply that is deeply aligned with China’s coastal industrial layout”.
Leveraging China’s extensive coastline and coastal industrial infrastructure, the project converts industrial waste heat into valuable resources, according to Dazhong.
It supports the development of energy networks in coastal regions, enabling the capture of local waste heat for the on-site production of green hydrogen using seawater.
The Shandong news outlet said that for port industrial cities such as Rizhao, this was not only a powerful tool for carbon reduction but also a new engine for green transformation. - SOUTH CHINA MORNING POST
