Off Scheveningen, an aging gas platform ran 8 miles of offshore cable to split seawater into hydrogen, and the rig never stopped pumping gas
A steel platform that has pumped natural gas from the seabed for decades now carries something new bolted to its deck.
Past the lifeboats and the old wellheads sits a small cluster of pipes and tanks nobody expected there.
They do not touch the gas stream at all.
A similar push toward squeezing energy from unlikely corners has turned up elsewhere, where researchers suspended a tiny chip to harvest small temperature gradients.
Instead they pull in seawater, strip it clean, and split it apart.
What comes out is a second fuel, made on a rig that was never built for anything but fossil extraction.
So how does an aging platform end up running a chemistry experiment on its own roof?
How a gas platform turns seawater into hydrogen
The process starts with raw seawater pulled up beside the platform’s legs. Before it can do anything useful, that water has to be stripped of salt and minerals until it is nearly pure, a step called demineralization. To produce green hydrogen, seawater is first converted into demineralised water on the platform, then converted into hydrogen through electrolysis.
That last detail is the hinge the whole project turns on. An electrolyzer is just a box that uses electric current to pry water molecules apart into hydrogen and oxygen, and it does not care where the electricity comes from. The electricity required for this process is supplied by offshore wind power, enabling the production of green hydrogen.
So the platform is not burning anything to make this hydrogen. It is borrowing electrons from the wind and handing back a fuel that burns clean. The platform used is a producing platform, which is the first fully electrified platform in the Dutch North Sea powered by renewable electricity.
What the rig actually looked like this summer
Picture a platform that still looks like every other North Sea gas rig from a distance: a steel lattice standing on legs driven into the seabed, a helideck, a flare boom. Then look closer at one corner of the deck, where a shipping container sized unit of pipes, valves and a small transformer has been wedged in among equipment that has nothing to do with it.
That unit is the entire hydrogen plant. PosHYdon integrates three energy systems in the North Sea, offshore wind, offshore natural gas and offshore hydrogen, and the project is being carried out on the platform located approximately 13 kilometers off the coast of Scheveningen. That distance works out to roughly 8 miles of open water between the rig and dry land.
Meanwhile, underneath that same deck, gas kept flowing exactly as it had before. Nobody shut anything down to make room for the experiment; the old infrastructure and the new chemistry now share the same stretch of steel, with a crew boat as the only regular visitor.
What the hardest numbers actually showed
The project’s backers were careful not to oversell a pilot. Its stated objective is to gain practical experience integrating operational energy systems offshore and producing hydrogen in a marine environment, in particular investigating the impact of offshore conditions, including exposure to salt, on the performance of the electrolyser.
That is a research program, not a commercial rollout, and the project treats it that way. The managing director of the platform’s Dutch operator, Lex de Groot, put the scale of the achievement in plain terms, describing the pilot’s progress as detailed on the project’s own public project page.
He said it was remarkable that, together with public and private partners, they had achieved a world first, and that reusing existing offshore platforms for sustainable applications is becoming a tangible reality. Behind the project sits a wide consortium rather than a single company chasing a headline, with oil and gas operators, grid specialists, an electrolyzer maker and a Dutch research institute all sharing the platform’s small footprint.
Where the idea still runs into limits
None of this means every aging gas platform in the North Sea is about to sprout an electrolyzer. The unit is small, built to prove the concept works at sea rather than to replace the platform’s main business.
Space on an offshore deck is scarce, corrosion is relentless, and a system this new has not yet logged years of saltwater weather. Even so, the fact that it ran at all, splitting water into hydrogen beside live gas wells without shutting either down, is the real finding here.
A similar push toward squeezing energy from unlikely corners has turned up elsewhere, where researchers suspended a tiny chip to harvest small temperature gradients. The team here also had to solve for wind that never blows at a constant speed, which complicates an electrolyzer built around steady input.
What comes after a pilot this small
The next test is whether lessons from one container sized unit scale into something a grid operator or industrial buyer would actually want. A Dutch research institute’s business director for energy infrastructure, Rene Peters, called the work an important step in scaling up offshore hydrogen production based on offshore wind, framing it as groundwork rather than a finished product.
That framing matters on a desk that tracks projects rather than promises. A single pilot platform will not replace the pipelines, tankers or storage caverns a real hydrogen economy would need, the kind of infrastructure gap also showing up in proposals like the underground reversible turbines now being tested for grid storage elsewhere.
What the platform did prove, in hard terms, is that an offshore structure built for one fuel can carry a second one without missing a beat. For an industry full of aging steel in open water, that is a more durable kind of good news than any single number from one summer’s test run.
Hugo is an engineer with strong technical expertise. Multilingual from an early age, his writing combines technical clarity with a strong interest in science and energy.
