Green hydrogen is produced by spiltting water molecules into H2 and oxygen through electrolysis. Deserts are great places to make green hydrogen at scale due to vast swathes of cheap land and high solar irradition resulting in low-cost renewable energy.
But with electrolysis requiring about nine litres of water for every kg of H2, where will desert projects get all their H2O from?
The standard answer is purpose-build water desalination facilities that take water from the sea and remove its salt. But what if the project location is far a body of water?
An Australian start-up believes it has the answer — and says it will reduce the cost of green hydrogen at the 10GW Desert Bloom Hydrogen project it is developing in the remote outback of Australia’s Northern Territory.
Aqua Aerem says that rather than adding to costs, producing water from air will actually be cheaper than the alternatives at the US $10.75bn scheme, which is to be built in the small town of Tennant Creek, almost 1,000km from the coastal city of Darwin.
“The project utilises proven technology in innovative ways to produce commercial quantities of green hydrogen without impacting water resources — significantly reducing the capital and operating costs associated with green hydrogen production,” the company explains.
And while one might think that desert air contains little water, the humidity levels — ie, the water vapour content in the air — the region still averages 23% in the driest month of October, rising to 45% in January.
Aqua Aerem — Latin for “water air” — is revealing little about its proprietary technology, other than to say it uses an absorber to capture water from arid air, that hotter climates increase the equipment's efficiency, and that it produces zero waste.
When water is extracted from air, it is usually through condensation — drawing warm air into a machine and cooling it until the water vapour reaches its dew point and turns to liquid.
“A majority of the green hydrogen projects announced globally are located in dry and water-stressed countries, yet have no clear strategy to access the necessary water,” Aqua Aerem says on its website. “Even those projects in regions that are not currently in water stress have demonstrated little focus on how water will be accessed reliably over the life of the projects.
“Aqua Aerem’s propriety water-making technology is powered by renewable solar energy and provides a much-needed solution to the water quandary that has so far curtailed the production of large volumes of green hydrogen required for the global energy transition.”
Desert Bloom project
Aqua Aerem plans to extract water from the desert air at its Desert Bloom Hydrogen project, which it claims is the “most advanced, shovel-ready green hydrogen project in Australia”.
And this week, the project received a boost when Japanese oil & gas operator Osaka Gas agreed to co-develop the facility.
Desert Bloom will be built using modular and portable 2MW "Hydrogen Production Units", which each contain the proprietary “water producing unit”, PV panels, an electrolyser, and a concentrated parabolic trough solar thermal heater. The hotter the air, the more moisture it is able to hold.
Aqua Aerem says that the project will produce green hydrogen at less than US$2/kg by 2027 and export about 410,000 tonnes of H2 per year when in full operation, making good use of “the world’s highest solar irradiation” and the site’s proximity to “key pipeline and transport infrastructure, and the Asia-adjacent port of Darwin”.
Details of the agreement with Osaka Gas are confidential, but Aqua Aerem says that Osaka Gas will collaborate on “project management, engineering and technical support... identifying customers and negotiating the sale of hydrogen from the project... [while] identifying, evaluating and negotiating with equipment manufacturers”.
Desert Bloom has already been awarded Major Project Status by the Northern Territory government and is financially backed by Singapore-based infrastructure investor Sanguine Impact Investment.
Sanguine’s managing director David Green, who is also chairman of Aqua Aerem, says the project will be “strategically beneficial to Japan”.
“Desert Bloom Hydrogen will produce revenue from the installation of the first module and does not require large upfront expenditure, including investment in large infrastructure that may become stranded or suffer from technological obsolesce,” he said.
“As a result of these substantial savings, Desert Bloom will be on track to produce green hydrogen at an export price international customers want to pay — less than $US2/kg within five years.”
Green added that Sanguine is in the process of increasing the project’s capacity to 20GW “to meet the quickly developing demand for green hydrogen”.
“An equitable global energy transition and water security are the key challenges of this generation and Aqua Aerem is well-placed to assist with the expected surging demand for reliable, affordable, green energy and provision of security water supplies,” he said.