Extracting water from desert air: unique 10GW green hydrogen project set to begin construction in 2022

The $10.75bn Desert Bloom facility in Australia’s Northern Territory is due to start commercial production the following year

Source: Recharge News | By Leigh Collins

The 10GW Desert Bloom green hydrogen project in the Australian outback — which will source water for the electrolysis process from the air — has been granted Major Project Status by the Northern Territory.

This means that the regional government will work with developer Aqua Aerem to progress the $10.75bn project to full scale, including identifying suitable locations in the sparsely populated Barkly region and fast-tracking each stage through the planning approvals process.

Aqua Aerem said the status will allow construction to begin on an initial 8MW test next year, ahead of a 400MW first phase, with “the production of commercial quantities of green hydrogen from 2023”. Upon completion in 2027, the project will produce about 410,000 tonnes of green H2 for less than $2/kg, making it cost-competitive with grey hydrogen made from unabated fossil fuels.

Desert Bloom is unique among an ever-growing global pipeline of gigawatt-scale green hydrogen projects because it will capture its water from the air. Electrolysers, which split water molecules into hydrogen and oxygen generally need nine litres of H2O for every kilogram of H2 — yet most giga-scale projects are situated in arid or semi-arid regions where high solar irradiation improves the levelised cost of H2 production.

“Our air-to-water technology, which solves this previously intractable water supply problem, is a world first; invented and developed here in Australia,” said Gerard Reiter, chief executive of Aqua Aerem, which means “water air” in Latin.

“This technology will open the door for green hydrogen projects to be located where the best renewable power sources are available, which is generally in the driest areas of the planet.”

Aqua Aerem offers little detail about how the technology works, only to say that it utilises an absorber that will “capture water from the atmosphere in arid environments... with increased efficiency in hotter climates”.

Most of the existing global pipeline of green H2 projects are expected to source their water from the sea through purpose-built water desalination facilities.

Despite the general lack of the rain in the arid/semi-arid Barkly region of the Northern Territory, the humidity levels — ie, the water vapour content in the air — still average 23% in the driest month of October, rising to 45% in January.

When water is extracted from air, it is usually through condensation — drawing air into a machine and cooling it until the water vapour reaches its dew point and turns to liquid.

The Northern Territory’s power utility, Territory Generation, intends to buy hydrogen from the initial stages of the project and use it to generate electricity at a gas-fired power plant in the nearby township of Tennants Creek. This will be an expensive way to produce power, as the round-trip efficiency of converting electricity to hydrogen and back again is usually about 30%, meaning that only 30kWh is produced from the original 100kWh.

In the longer term, the developer aims to utilise existing natural-gas pipelines to transport its H2 900km north to Darwin for export to Asia, although local ammonia production is also being considered.

Desert Bloom will eventually consist of thousands of moveable 2MW containerised modules called Hydrogen Production Units that utilise PV panels, concentrated parabolic solar thermal heaters, the patented air-to-water equipment, and electrolysers — thus generating water, heat, electricity and hydrogen.

Singapore-based Sanguine Impact Investment, Aqua Aerem’s majority shareholder, has already taken a financial investment decision to provide the project with an initial A$1bn ($977m) — and further investment is expected to come from “one of Japan’s largest gas buyers and distributors”, the developer says.