Producing green hydrogen on a gigawatt scale

Hydrogen plays an important role in the energy transition. However, to achieve the 2030 climate targets, a significant jump in scale is required in producing green hydrogen. The current production facilities have megawatts capacity, while we should have gigawatt installations up and running within eight years. But what do those green hydrogen plants on a gigawatt scale look like, and what do they cost? A broad consortium led by the Institute for Sustainable Process Technology (ISPT) made a promising conceptual design for such a plant.

By Hans van’t Noordende, ISPT

The production of green hydrogen is technically not a brain teaser. Electrolysis technology to make hydrogen from demineralised water has been around for about a century. The challenge is mainly to make a jump in scale to make green hydrogen competitive in price. There are several preconditions for the necessary increase in scale (see box). EU and national governments must ensure that green hydrogen production is profitable with new regulations.
In addition, we need a growing capacity for offshore wind to keep future hydrogen factories running for sufficient hours per year.
Another condition for large-scale implementation of green hydrogen is clarity about the capital expenditure for a gigawatt hydrogen plant. What are the costs for a factory? Can smart applications of advanced technologies, materials and optimisations reduce costs to such an extent that green hydrogen becomes an attractive alternative for industry?

From megawatts to gigawatts

Hans van 't Noordende, ISPT

To meet the energy needs of industry, transport and other sectors, we need to produce enough hydrogen. The European ambition is 40 to 60 gigawatts by 2030. By way of comparison: until recently, the largest existing hydrogen factory had a maximum capacity of 10 megawatts. So we need an enormous, affordable upscaling within 8 years.

Hydrohub Gigawatt Scale Electrolyser project

The Hydrohub Gigawatt Scale Electrolyser project has answered the question of how we can produce green hydrogen in the Netherlands cost-efficiently and on a large scale. Furthermore, we looked at how to improve the performance and which electrolysis technologies have the best potential in terms of costs, flexibility and heat recovery. Advice on geographics and how the basic design for a hydrogen plant with a capacity of 1 gigawatt would look were also provided.
“We looked at where the factories could be located in the five Dutch industrial clusters and identified 22 potential locations,” says Hans van’t Noordende, technical project leader at ISPT.
“In consultation with industrial companies, network operators and governments, we mapped out how such a factory fits their needs and projects, where we can extract water and electricity, how to distribute hydrogen in the smartest way and how to use the residual heat.”

Figure 1. An artist’s impression of an advanced AWE 1-GW green-hydrogen plant
Figure 1. An artist’s impression of an advanced AWE 1-GW green-hydrogen plant
Figure 2. An artist’s impression of an advanced PEM 1-GW green-hydrogen plant
Figure 2. An artist’s impression of an advanced PEM 1-GW green-hydrogen plant

Advanced design for AWE and PEM factory

Engineers and scientists worked on an advanced design for an energy- and cost-efficient factory. They worked out the design for both an alkaline technology (AWE) plant and a plant with electrolysers using PEM: proton-selective polymer membranes.The team looked for innovations, improvements and optimisations at each process step in the design. Various innovations in the electrolysis stacks and scaling-up potential to larger units were investigated.
For example, both types of electrolysers use advanced electrode materials and thinner, state-of-the-art materials. In addition, higher operating temperatures are considered, assuming that the degradation of electrodes is controlled. As a result, a better performance expressed as H2 productivity per kW could be achieved with fewer stacks.
The number of cells per stack has also been increased. The AWE stacks have 335 cells with a total capacity of 20 megawatts. The PEM stacks use half that power with 310 cells.
“The anodes contain lower amounts of iridium, which means that we are less dependent on this scarce raw material for constructing hydrogen factories,” says Van ’t Noordende. The electrolysers form modular units of 160 megawatts (AWE) and 40 megawatts (PEM). “This modular structure makes it possible to scale up factories cost-effectively.”

Figure 3. Scope of a greenfield 1-GW green-hydrogen plant based on AWE technology.
Figure 3. Scope of a greenfield 1-GW green-hydrogen plant based on AWE technology.
Figure 4. Scope of a greenfield 1-GW green-hydrogen plant based on PEM technology.
Figure 4. Scope of a greenfield 1-GW green-hydrogen plant based on PEM technology.

Collaboration of industry & institutes

In the Hydrohub Gigawatt Scale Electrolyser project, ISPT collaborated with industrial partners Dow Chemical, Gasunie, HyCC, OCI, Ørsted and Yara, and knowledge institutes TNO, Imperial College London, TU/e and Utrecht University. The Hydrohub Gigawatt Scale Electrolyser project is part of ISPTs Hydrohub Innovation Program.

Material selection

For alkaline water electrolysis technology with (30%KOH) caustic services at higher temperatures (90-100°C), stress corrosion cracking is the dominant corrosion mechanism. For PEM technology, dealloying is the main corrosion type.
In the case of Alkaline separators, CS Ni clad (3mm) is the most cost-effective material at these temperatures.
For piping with KOH/H2 service SS310S, Duplex 2906 materials are preferred, whereas for KOH/O2 service Ni-200, high Ni alloys (20, 600, 800) are needed.
In the case of PEM, ultra-pure water is used. Therefore, the material considered is SS316 for piping and for rotating and static equipment.
The main concern is the leaching of Fe(II) and other elements leading to the deactivation of catalyst materials with an adverse impact on PEM stack performance and lifetime. Extensive water treatment may be needed to remove these highly diluted elements.

Skip hydrogen compression

Another improvement in the design was to increase the pressure in the AWE electrolysers to 5 bar, Van’t Noordende reveals. “That way, we skip the first expensive step of hydrogen compression. The hydrogen must then be further compressed to 30 bar for the end users. For PEM, that pressure of 30 bar is already there, so extra compression is not necessary, making a PEM installation slightly more efficient. But both types of stacks have nearly 80% system efficiency.”
The AWE stacks operate at a temperature of 100°C, in the PEM it is at 70°C. The design also takes into account heat recovery from the cooling water. Regional heat networks could make use of this.
The engineers are also taking advantage of opportunities to optimise the electrical installations of the hydrogen plant. A cost-effective layout has been designed with 380 kV/66 kV transformers in combination with low voltage transformers and active control semiconductor rectifiers called Insulated-Gate Bipolar Transistors (IGBTs). That
is in accordance with the network requirements. The transformer and rectifiers form independent e-houses, which makes the design particularly compact.

Continue with R&D, pilots and demonstrations

On an area of approximately 10 hectares, the hydrogen factory houses everything needed for electrical installations, electrolysis, purification and compression to supply hydrogen in line with the fluctuating supply of sustainably generated wind energy and in accordance with the demand of the end users. Nevertheless, R&D, pilots and demonstration projects are still needed to implement technological innovations that allow further cost reductions.
A major advantage of the Hydrohub Gigawatt Scale Electrolyser project is that there is a concept or design on paper. In fact, the project team has even made a virtual reality model and animation film that allows you to walk through the factory; visit http://bit. ly/3IQrGV0

TKI Energy & Industry

The Hydrohub Gigawatt Scale Electrolyser project was co-financed by TKI Energie en Industrie, part of the Energy Top Sector, with the additional subsidy ‘TKI-Supply’ for Top Consortia for Knowledge and Innovation (TKIs) from the Ministry of Economic Affairs and Climate.

Comparison of advanced design (2030) compared to baseline design (2020).
Comparison of advanced design (2030) compared to baseline design (2020).

ISPT innovation platform

As a platform, ISPT brings parties together to work on making the industry more sustainable. “Together with our partners in the industry, we put issues on the agenda and define projects. In 2017 we started this Hydrohub Gigawatt Scale Electrolyser project, and worked with the most suitable implementing parties to form a strong consortium and get results. This project is part of ISPTs hydrogen program, the Hydrohub Innovation Program.

Interested in learning more?

Public report ‘A One-GigaWatt Green-Hydrogen Plant’:
About the Hydrohub Innovation Program:
About he Hydrohub GigaWatt Scale Electrolyser:
Virtual reality model & tour:

About ISPT

As an energetic and open innovation platform for sustainable process technology, the Institute for Sustainable Process Technology (ISPT) connects stakeholders from different sectors and disciplines. We innovate and pioneer to accelerate a more sustainable industry. The industry is an essential player in achieving a circular economy in 2050. It is a driver and connector in the reuse of residual and waste flows, the integration of electricity demand, the development of hydrogen as a feedstock and energy carrier, and so on. Together we are committed to the transition to a circular and CO2-neutral process industry in 2050. Visit for information.

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