The world’s first commercial-scale green-hydrogen plant to be powered solely by surplus offshore wind energy has been announced by a trio of Belgian companies.

Offshore engineer DEME, Flanders-focused financier PMV and the Port of Ostend plan to build a 50MW demonstration project at the port — set to be the world’s largest electrolyser plant — before completing an even bigger, commercial-scale unit in 2025.

It has long been suggested that excess renewable energy that cannot be absorbed by the grid should be diverted into the production of green hydrogen, rather than being curtailed, via a process known as electrolysis — using electricity to split water molecules into hydrogen and oxygen. But this is the first project to be announced that specifically aims to power electrolysers using only excess renewable power.

Other green H 2 projects announced to date are seeking to receive their power from dedicated renewables projects, as green hydrogen becomes cheaper to produce the more hours per day the electrolysers are operating.

The three companies point out that Belgium will have 2.26GW of offshore wind installed by the end of this year, with a further 1.75GW to be developed.

“However, the wind turbines’ production peaks rarely coincide with consumer demand peaks, meaning that there is an opportunity to compensate for the discontinuity between production and consumption,” they explained in a statement.

The green hydrogen at the Hyport Oostende project would “serve as an energy source for electricity, transport, heat and fuel purposes and as a raw material for industrial purposes”, the companies said.

“With our energy transition in mind, we need to be able to temporarily store our green energy surplus using hydrogen as an energy carrier or to use hydrogen as an alternative raw material for converting the industry away from fossil fuels.”

Hydrogen can be converted into electricity using a fuel cell or burned like natural gas to produce power (via a turbine) and/or heat, with both processes emitting only water vapour. As hydrogen can be stored indefinitely, it is being touted as a long-term form of energy storage.

The Hyport Oostende project will have an element of energy storage, with the companies announcing that “by 2022, the roll-out of a large-scale shore-based power project, running on green hydrogen, will start”.

About 69 million tonnes of hydrogen are produced every year, largely for use in oil refining, fertiliser production and a host of other sectors where H 2 is a core part of a product’s DNA.

About 99% of this hydrogen is derived from fossil fuels, releasing 830 million tonnes of CO 2 into the atmosphere every year, according to the International Energy Agency — more than the UK, France and Belgium combined. The main hydrogen-producing process, steam methane reforming, releases nine to 12 tonnes of CO 2 into the atmosphere for every tonne of H 2 .