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Hydrogen sector targets production boost

Energy losses in the production process contribute to making hydrogen produced with renewable energy expensive. Companies and researchers are working to improve the efficiency of electrolyser technology and scale it up, bringing down the green hydrogen price tag at the same time

Improving electrolysis efficiency could help make green hydrogen a competitive option


ECONOMIES OF SCALE Costs of hydrogen will come down as electrolyser capacity is rolled out worldwide MATTER OF TIME To make an impact on the energy transition, green hydrogen needs to make gains in efficiency and cost competitiveness before other technologies mature KEY QUOTE
Prices will have to fall significantly if green hydrogen is to be economically feasible at some point


As the Intergovernmental Panel on Climate Change (IPCC) states in its latest report: As a general rule, and across all sectors, it is more efficient to use electricity directly and avoid the progressively larger conversion losses from producing hydrogen and ammonia.”

But advocates of hydrogen produced from renewable energy—known as green hydrogen—promote its role in reaching net-zero targets, particularly in hard-to-abate sectors such as steel and chemical production, heavy transport and aviation.

Demand for green hydrogen will grow to 500-800 million tonnes a year by 2050 to meet the needs of these sectors, creating a new multi-trillion-dollar industry, expects the Energy Transitions Commission, a coalition of energy companies, financial institutions and NGOs.

However, building up a green hydrogen industry of these dimensions will not be easy. One major obstacle to growth lies in the inefficiency of green hydrogen production. Narrowing the efficiency gap compared with direct electrification is essential for green hydrogen to be competitive.

Most of the cost of producing green hydrogen comes from the renewable electricity needed to power the process, with the electrolyser accounting for the majority of the remainder. The more efficient the electrolyser, the less electricity is wasted and the lower the cost of green hydrogen.

Electrolysers used to split water into hydrogen and oxygen now run at 65% efficiency according to the -International Renewable Energy Agency (IRENA), while analysts at the consultancy Wood MacKenzie put the end-to-end efficiency of green hydrogen production at 30%.

EFFICIENT ELECTROLYSERS

Hysata, a spin-off from the University of Wollongong in Australia, aims to commercialise breakthrough hydrogen electrolyser technology. It revealed in an article published in the March 2022 issue of Nature Communications that its capillary-fed electrolysis cell technology can produce green hydrogen from water at 95% cell energy efficiency, well above IRENAs 2050 target of 76% and what is currently achieved by existing electrolyser technologies. This adds up to a hydrogen production cost well below A$2 per kilogram, Hysata claims.

Efficiency gains have been achieved by reducing the electrical resistance within the electrolysis cell. This resistance wastes energy and requires additional energy for cooling. Hysata’s team develop a thin sponge-like membrane to suck the water up between two electrodes.

Unlike typical electrolysers, this technique does not create gas bubbles during the operation of the electrolysers, removing the need for equipment to circulate the liquid. The technique also self-cools, eliminating the need for water-cooled chillers.

The technology will save hydrogen producers billions of dollars in electricity costs and enable green hydrogen to outcompete fossil fuel-derived hydrogen, claims Paul Barrett of Hysata. The overall system has been designed for ease of manufacturing, scaling and installation, which also cuts the capital costs of producing green hydrogen.

Barrett says Hysata is on track to commercialise its electrolyser and reach gigawatt-scale hydrogen production capacity by 2025. The company plans to build a pilot electrolyser manufacturing plant in 2022.

In the United States, researchers from the Georgia Institute of Technology are developing high-performance catalysts to make electrolysers more energy efficient and are using artificial intelligence in this process, explains Seung Woo Lee of the institute’s George W Woodruff School of Mechanical Engineering.

Before jumping into the synthesis of any new materials, we wanted to down-select candidate materials to figure out what would be the most promising one that exhibits high performance in the water splitting. We use machine learning as a tool for this process based on a database of materials investigated by other researchers, as well as our team, an approach we believe holds great potential to accelerate our research,” Lee says.

Elsewhere, Siemens Energy has several research and development projects on electrolysers. The company uses Proton Exchange Membrane (PEM) electrolysis technology—a type of fuel cell, which is dominating hydrogen projects at the moment—and is developing systems with the capacity to produce several tonnes of green hydrogen per hour.

Siemens has signed a partnership with French company Air Liquide to combine their expertise in PEM technology to develop industrial-scale hydrogen projects, laying the groundwork for mass manufacturing of electrolysers in Europe, especially in Germany and France, and research and development activities to co-develop next-generation electrolyser technologies.

The two companies will jointly apply for large project funding under the EUs Green Deal and Important Project of Common European Interest (IPCEI) scheme for hydrogen, funded by the French and German governments. They are already working on the Air Liquide-H2V Normandy electrolyser project in France, which has a capacity of 200 megawatts (MW) and is scheduled for commissioning in 2025.

UPSCALE DEPLOYMENT

Research and innovation in electrolysers are key to increasing the viability of green hydrogen, according to Alexander Esser of Aurora Energy Research. Scaling up the global deployment of electrolysers is paramount as we currently have just a few of them installed and these are still often in a prototype phase. We believe that costs will come down with innovation and scaling, very similar to what we observed with wind turbines or solar panels,” says Esser.

The EU has a 40 gigawatt (GW) target for electrolysers in operation by 2030. If recent commitments contained in the hydrogen strategies of member states are respected, this target will be met on time. This is great news as this deployment will accelerate innovation and bring the costs down,” says Esser.

Prices will have to fall significantly if green hydrogen is to be economically feasible at some point,” says Steve Scrimshaw of Siemens Energy. To reduce electrolyser costs and meet rapidly growing demand, industrial-scale, automated production is essential, he adds. This would further improve efficiency.

Electrolysers are generally produced using a lot of manual labour, allowing for the production of small quantities. Siemens will instead use digitalisation, robots and serial production techniques in a new electrolysis factory in Berlin, set to be operational in 2023. The aim is to realise electrolysers in large dimensions and with high performance. The efficiency of electrolyser production will be enhanced significantly,” says Scrimshaw. Siemens is targeting electrolysis efficiency of 75.5%.

David Burns of Linde agrees that scaling is part of the answer. The multinational industrial gas company can produce green hydrogen at an efficiency of 53 kilowatt-hours (kWh) per kilogram, he says. The company is currently building a 24 MW electrolyser in Germany, which will be the biggest PEM electrolyser in the world, he adds.

Linde is also working with UK-based oil firm Shell on a 100 MW electrolyser in Wessling, Germany, while another partnership with German energy company RWE will see two 100 MW electrolysers installed in Lingen, as part of RWEs roadmap to install a 300 MW of electrolyser capacity by 2026. But to get the scale you need for green hydrogen, projects need to be in the gigawatt range. It’s a gradual ramp up, we’re getting into 100 MW projects now,” Burns says.

In the future, solid oxide electrolysers could provide an opportunity for more efficient production of green hydrogen. Operating at higher temperatures, they could be an option in particular applications such as steel manufacturing, where there is potential for heat integration with high-temperature sources. However, the technology is still some years away from maturity, according to Burns.

In the meantime, Linde is developing high-efficiency PEM electrolysis projects. To boost efficiency, Linde is considering all aspects of its design: the size of the membranes and the gap between them, voltage drop and technologies that can tolerate higher current densities without degrading, Burns explains.

There’s a number of different trade-offs, but there’s a lot of attention going into PEM today so that seems to offer the most potential, mid- to long-term and then technology like solid oxide will probably come on later,” he adds.

Linde is also evaluating water treatment, power sources, supporting infrastructure and distribution, including the pressure being put into the pipeline and how much heat is being distributed as a liquid. You have to look at the whole system when you look at it from an efficiency point of view,” Burns says.

LEARNING FROM EXPERIENCE

As well as developing scalable technology platforms, Scrimshaw from Siemens believes that learning by experience from different projects will be key. We really need these feedback loops to improve the processes; funding of projects and the right regulatory framework are key here, such as quotas or CO2 taxation regarding e-fuels. We also need to prepare the supply chains to scale and we must enable a reliable service structure to keep the plants running,” he says.

As the green hydrogen energy industry scales up, the efficiencies of producing hydrogen from renewable energy are expected to improve and costs fall. Esser estimates that the Capex of PEM electrolysers will decrease by around 40% by 2030, while efficiency will increase to 69%. Alkaline electrolysers will follow a similar trend, he says.

French energy group EDF expects that for some time green hydrogen will be mostly used for activities that cannot be decarbonised otherwise, such as plastics, fertilisers or petroleum refining for heavy transport.

It argues that the inefficiency of the production process means that using green hydrogen to replace gas in power plants or as storage for renewable energy, both for which alternatives are technically possible, will not make economic sense before 2040 or 2050 by which time, alternatives may have matured. •


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Catherine Early PHOTO Chris Leipelt