The 100MW Greenhyscale project in Denmark is developing a system that will tell customers how green the hydrogen they are buying is, according to the project developers.

The plant will run on 80MW of directly connected renewables topped up with electricity from the grid when needed. Because Denmark’s electricity grid mix can contain variable rates of coal- and gas-fired generation at any particular time, this means that hydrogen produced by the electrolyser will have a different CO₂ footprint depending on when it was produced.

“It’s up to customer to determine how green it needs to be,” says Ander Boje Larsen, CTO of project manager Greenlab, speaking on a recent webinar.

100MW – Planned size of project by 2024

“If it needs to be fully green, we have developed systems that can certify that,” he adds. This would be hydrogen produced when only the directly connected renewables powered the electrolyser or when the grid had no fossil-fuel generation running.

The same system is able to provide detailed information on the grid mix at the time of green hydrogen production, enabling customers to calculate its carbon footprint and whether it falls within the necessary certification criteria for their needs.

There is no globally accepted definition on what qualifies as ‘green hydrogen’. The EU is currently consulting on two delegated acts that will provide a clear technical definition and will set a benchmark for EU projects and those that are looking to export to the bloc.

Modular approach

The Greenhyscale project uses a modular alkaline electrolyser platform delivered by Danish manufacturer Green Hydrogen Systems.

A 6MW module was demonstrated as the first step in the project, which is now operating at 24MW. The project will be scaled up to at least 100MW from 2024.

Modular units are easier to ramp up and down than a large electrolyser, helping the facility cope with intermittent renewable generation. The facility can go from operating 16pc of one 6MW module to the full 24MW in less than five seconds.

The project will act as a grid-balancing service provider as well as meeting demand for local transport and industrial applications and aims to produce green hydrogen at below €2.85/kg ($2.87/kg). It has received a €30mn grant from the EU’s Horizon 2020 funding programme.

A 7.5MW electrolysis module suitable for positioning adjacent to offshore windfarms is planned for Greenhyscale’s second phase.

“The potential for offshore energy in the North Sea is so high that it is too high for the grids to handle. It needs to be converted to hydrogen offshore,” says Kasper Therkildsen, CTO of Green Hydrogen Systems, speaking on the same webinar. “We see a big role for this in the future.”

The project has eleven participants, including Norwegian energy company Equinor and wind turbine manufacturer Siemens Gamesa.

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Author: Tom Young