Water sustainability issues in green hydrogen production

Alternative water sources provide a sustainable pathway for water-scarce economies, like Australia, to produce large amounts of green hydrogen.

Green hydrogen is produced when water electrolysis is powered by renewable energy to split water into hydrogen and oxygen. Green hydrogen can be stored, transported and burned to generate power. Green hydrogen production does not result in carbon emissions.

Green hydrogen is an important technology in the shift towards cleaner energy. It can help reduce carbon emissions in applications and industries that are hard to decarbonise, for instance, by serving as a zero-carbon fuel in the production of energy-intensive materials such as cement, steel and chemicals. Additionally, it can serve as a direct replacement for natural gas in power generation.

Green hydrogen can be turned into higher-value derivatives such as green ammonia, green methanol and Sustainable Aviation Fuel. It can serve as a form of chemical energy storage to complement and provide a reliable alternative to lithium-ion batteries. It can also power zero-emissions vehicles using hydrogen fuel cells.

Australia has committed over AU$1.3 billion to develop its hydrogen industry as part of efforts to become a renewable energy superpower, decarbonise its economy and increase clean energy exports to contribute to regional and global decarbonisation with concomitant benefits to energy security.

Abundant renewable energy and land are resources that Australia offers to support its ambitions. It will also require an enormous amount of high-quality water for hydrogen production.

Water is required to perform key functions in hydrogen production including:

• Critical feed for production.
• Plant cooling and domestic water.
• Disposal of rejected water from treatment processes.
• Salt cavern solution mining for geophysical hydrogen storage.
   

A study in the Journal of Cleaner Production proposes that producing 1 kilogram (kg) of hydrogen through water electrolysis requires 9 litres (L) of ultra-pure water. The total water usage of a hydrogen plant can range from 18 to 36 L/kg of hydrogen, depending on the plant’s configuration.

According to Black & Veatch’s analysis, assuming an electrolyser-specific energy consumption of 55 kilowatt-hours per kilogram (kWh/kg), a 1-gigawatt (GW) hydrogen facility can consume approximately 7 to 15 million L of water per day.

Swinburne University of Technology estimates that about 225,000 megalitres (or 225,000 million litres) of water will be needed for Australia to achieve its AU$50 billion green hydrogen industry. This amount of water is estimated to be around 4% of the amount of water used for Australian crops and pastures in 2019–20, based on Australia Bureau of Statistics data in 2022.

This is a large quantity of water, especially in water-stressed areas.

On top of that, the declining availability of fresh water caused by climate change is making it challenging to manage water resources effectively in water-stressed economies, including Australia. Variable rainfall patterns worsen the impact of drought and aggravate the situation.

Sustainable pathways

In Australia’s arid regions, most available water resources have been allocated for agricultural irrigation and town and city drinking water supplies.

Opting for alternative water supplies, such as desalinated water and recycled wastewater, can sustain hydrogen projects and reduce the withdrawal of existing surface and groundwater resources.

Seawater could be a potential stable supply for hydrogen facilities located near coastal areas, while plants near cities with large, centralised wastewater treatment facilities can turn to recycled wastewater as a viable alternative.

Seawater and recycled wastewater can be treated to the quality needed for hydrogen production. Additionally, the salinity of salt water can be lowered by reverse osmosis. Ultrapure water produced after the final polishing treatment process can then be used for hydrogen production.

As alternative water resources do not deplete existing resources, including local drinking water supplies, they are more likely to be accepted socially. Additionally, water supply alternatives can be recycled back into the hydrogen production process and treated to a higher quality than the original water source.

Regionally, PT Freeport Indonesia (PTFI) appointed Black & Veatch to design and manage the delivery of a seawater desalination plant for its Manyar Smelter in East Java, Indonesia. The seawater desalination plant will support the processing of mine concentrates from the Grasberg mine in West Papua.

Globally, seawater desalination projects that Black & Veatch worked on include the Escondida Water Supply Expansion (EWSE) project at the Minera Escondida mine in Chile and the original Escondida Water Supply (EWS) project.

For Australia’s Bundamba Advanced Water Treatment Plant (AWTP), Black & Veatch and its joint-venture partners designed, constructed and commissioned one of its three water treatment plants on a fast-track schedule. Water treatment steps at the Bundamba AWTP include ultrafiltration membranes, reverse osmosis membranes followed by advanced oxidation using ultraviolet irradiation and hydrogen peroxide.

For Melbourne Water Corporation’s Eastern Treatment Plant (ETP) in Victoria, Black & Veatch selected a process train of ozonation, media filtration, ultraviolet irradiation and chlorination that significantly improved the quality of discharge into the environment. The process produces high-quality recycled water that the community can use.

Creating bankable projects

While desalination offers a sustainable and climate-resilient water supply for hydrogen generation, it also comes with high energy and production costs. Treatment and regulatory permitting can add to the challenges.

Powering desalination plants with renewable energy sources can help to reduce carbon emissions from the desalination process and provide a rainfall-independent water supply that meets environmental and commercial targets.

Another factor to improve project bankability is locating a high-quality water source before constructing the hydrogen plant. This includes siting seawater desalination facilities near coastal areas to reduce water conveyancing costs.

It also includes seeking water recycling and effluent reuse opportunities near major cities where greywater sources and wastewater treatment facilities are commonly located.

Planning for water holistically can reduce the risks associated with resource over-allocation. This strategy includes implementing an integrated water management system that advances the sustainability objectives of Australia’s hydrogen industry.

The system would ideally evaluate the water consumption of hydrogen projects and create plans that balance the requirements of the hydrogen sector and those of local water users.

Equally critical are supportive water management initiatives at the national level, including the use of alternative water sources and simplifying the permitting process for alternative water infrastructure.

Water management and allocation frameworks can also help prioritise the sustainable development of the hydrogen sector.

Planning ahead

The viability of Australia’s hydrogen economy depends on how effectively it manages the competing water demands from various users, including industry, commercial and residential sectors.

Incorporating appropriate technologies for hydrogen manufacturing, alternative water sources and process cooling can help optimise water usage and present opportunities for sustainable development.

To identify the right mix of technologies and scale them, the industry needs partners who can support its strategic decision-making, financial and resource commitments, implementation and execution.

James Currie is Director, Water, Associate Vice President, Australia Pacific at Black & Veatch. Black & Veatch has been supporting Australia’s water infrastructure development for over 40 years and remains committed to it.

Top image credit: iStock.com/Olemedia