A disused fuel rig recently became a British art installation. What will happen to the rest?

Decommissioning an oil or gas platform is a mammoth task, and the industrial tangle above the water is only a tiny bit of what must be dealt with as they approach the end of their life. So how are they dismantled – and what happens next?

By Dominic Bliss
Published 23 Nov 2022, 14:45 GMT
SEE MONSTER, © Ben Birchall, Courtesy UNBOXED: Creativity in the UK (2022) and NEWSUBSTANCE (2).JPG

The SeeMonster art installation, which was created from a decommissioned gas platform and situated on the waterfront at Weston Super-Mare, Somerset during October and November 2022. 

Photograph by © Ben Birchall, Courtesy UNBOXED: Creativity in the UK (2022) and NEWSUBSTANCE (2)

Dotted around the planet, rising out of the sea, are thousands of oil and gas platforms. A large number stand in the UK waters of the North Sea. As the world gradually releases itself from the stranglehold of fossil fuels, all these platforms will become redundant. What will happen to them, though? Can they be recycled or re-used? Or will they just languish in place, slowly rusting away?

At Weston-super-Mare, just south of Bristol, on the Severn Estuary, a former North Sea gas platform was recently given a second life as a giant art installation. Rechristened SeeMonster, the 450-tonne, 35-metre-tall hulk of rusty steel enjoyed eight weeks on the beach of this seaside town, dominating the skyline. Visitors could climb a stairway up to its three levels. There were wind sculptures, a waterfall, a tube slide, a tiny amphitheatre, dozens of plants, and impressive views both inland and out to sea. On 21 November 2022 SeeMonster began its dismantling process, and after its brief moment in the sun, is due to re-enter its decommissioning cycle in January 2023.

SeeMonster’s journey from the North Sea to the Severn Estuary was long and convoluted. Leeds-based creative studio Newsubstance oversaw the entire project. The studio’s engineering director Mike Birch wouldn’t reveal who originally owned the platform, nor exactly where in the North Sea it used to sit. But he explained to National Geographic (UK) how it had first been cut from the steel support structure (known as a jacket) anchoring it to the sea bed, before being transported to a decommissioning yard in the Netherlands, and from there on a vast floating barge along England’s south coast to Weston-super-Mare.

As far as Newsubstance are aware, SeeMonster is the world’s only example of an energy platform converted into an art installation. Once defunct, most platforms end up being scrapped, recycled, or simply left in place.

Tip of the iceberg

Sam Long is chief executive of Decom North Sea, an organisation promoting “safe and environmentally sound decommissioning in the energy sector”. He stresses the enormous costs and complicated engineering involved in removing or dismantling these structures. The platforms and living quarters (known as topsides) that we see emerging from the sea surface, and the jackets supporting them, are merely the tip of the iceberg.

“Everyone gets excited about the jacket and the topside of these platforms,” he tells National Geographic (UK). “But that’s just one small part of an industrial machine. The real infrastructure are the pipelines that connect it and the wells in the ground that connect to the [oil and gas] reservoirs.”

There are varying types of energy platforms – fixed, floating or sub-sea, among others. It’s the fixed ones that often require the most complicated decommissioning processes, lasting up to seven years in some cases, from concept to completion.

The Eider platform, 60 miles northeast of Shetland, North Sea. Part of the Eider oil field, this platform can accommodate 73 people and stands in water depth of 157 metres.

Photograph by Nature Picture Library / Alamy

As Long explains, once the relevant permits are in place, the first stage is known as P&A (plugging and abandonment). “This shuts down the reservoir so that oil or gas can no longer come back up the well bore,” he says. Typically, the well is plugged with metal and concrete, in an attempt to recreate the bedrock that once sat above it.

Then the platform must be separated from the well. “Modern platforms are designed with removal in mind, but older platforms were built without people thinking about removal,” Long says.

Next, the entire infrastructure must be stripped of all its hazardous materials. This includes all the hydrocarbons, but there might be asbestos there, even naturally occurring radioactive materials, known as NORMs. “If the platform has been producing 40,000 barrels of oil a day for the last 20 years, it might have drawn up tiny amounts of natural nuclear material all the time,” Long explains. “Not every platform has NORMs, but this is another part of the decommissioning process.”

Now the platform is ready to be removed. It might be broken into separate sections or, if a large enough vessel is available, it might be towed away all at once. Pioneering Spirit, for example, the largest construction vessel in the world, is capable of lifting and transporting entire topsides up to 48,000 tonnes in weight and jackets up to 20,000 tonnes. Normally the various components are transported to decommissioning yards on dry land before being carved up and recycled.

The legs of a decommissioned oil rig stand in the Cromarty Firth, Scotland. While the 'topside' portion is the most obvious above sea level, the giant infrastructure of the rig lies out of sight – including the drills, 'jacket', and the pipeline. 

Photograph by StockShot / Alamy

The Brent Alpha topside is floated into the Tees river at Redcar on the 200m barge Iron Lady, June 2020. 

Photograph by Trevor Wilkinson/MI News/NurPhoto

Safe disposal

Regulations on disposing of old platforms differ enormously, depending on which ocean the metalwork happens to stand in. In the Northeast Atlantic there’s a marine convention called OSPAR, representing 15 European nations, including the UK. Deputy secretary Laura de la Torre explained to National Geographic (UK) that energy companies are prohibited from “dumping, and leaving wholly or partly in place” disused offshore installations that sit within OSPAR’s jurisdiction. This only applies to structures weighing less than 10,000 tonnes, however. Owners of heavier structures can apply to leave them in place, provided they manage and monitor them. 

The UK government regulator for this industry is the North Sea Transition Authority (NSTA) which encourages energy companies to recycle their defunct platforms. “Most decommissioning yards aim to recycle a high percentage of the materials that come ashore, for example more than 95 per cent,” a spokesperson told National Geographic (UK).

There are other, occasionally more dignified retirement plans. According to the NSTA, defunct oil and gas infrastructure could be repurposed for storing carbon dioxide or hydrogen fuel. But it’s the pipelines rather than the structures that are likely to be used.

“Initial analysis suggests that opportunities for repurposing platform topsides, jackets and subsea systems for decarbonisation projects are likely to be limited,” the authority states. “Pipelines are the real prize, and they are being prioritised.”

Passers by highlight the scale of the stricken Transocean Winner rig topside, which ran aground in heavy seas on the Isle of Lewis in 2016 after the line between the rig and its tug broke.

Photograph by PA Images / Alamy

One major energy company, Eni UK, wants to go even deeper. Through its project HyNet North West, it proposes storing carbon dioxide in depleted natural gas reservoirs in the seabed below the Hamilton, Hamilton North and Lennox fields, in Liverpool Bay, and below the Hewett field, off the coast of Norfolk.

Back to nature

Aquaculture is another intriguing option. In U.S. waters (and to a much smaller extent in waters off the coasts of Malaysia and Brunei), a practice known as rigs-to-reef has seen platforms converted into artificial reefs. Some are cut in two or toppled onto their side, while others are towed to a more suitable location. In the United States, the government’s Bureau of Safety and Environmental Enforcement counts a total of more than 600 platforms that have been converted into reefs in the Gulf of Mexico. They claim it’s not uncommon for thousands of fish to make platforms their homes.

David Cresson is chief executive of the Coastal Conservation Association of Louisiana. “The oil and gas platforms in the Gulf of Mexico provide some of the most abundant and productive habitats on Earth, and in doing so create exceptional opportunities for recreational anglers and divers,” he explains.

Environmentalists aren’t so keen. Dr David Santillo is a marine biologist with Greenpeace. “Our view is always that human infrastructure that’s in the sea should only be there for as long as it’s serving a purpose, and that we should remove it and let things get back to as natural a state as possible,” he tells National Geographic (UK.)

A rig mothballing/decommissioning yard in Santa Cruz port, Tenerife, in the Canary Islands. This plant deals with many of the oil rigs from the south Atlantic, whose usage varies depending on the fluctuating price of oil. 

Photograph by Alan Dawson / Alamy

He stresses the importance of underwater sediment for the biodiversity of marine eco-systems, and for natural carbon capture. “We don’t support the argument that it’s actually good for the marine environment if you leave [defunct oil and gas platforms] behind. If you put a hard substrate in an area where there’s ordinarily soft sediment, you will eventually get marine species attaching to that because there are always larvae drifting through these areas. You can say: ‘Look, this is a good thing, because we’ve increased the biodiversity in this area.’ But if naturally those species wouldn’t normally occur there, that’s a huge value judgment as to whether it’s positive for the marine environment or not.”

Santillo worries we may end up with what he calls “reefs of convenience”. “The argument can be made that there are things growing on [the reefs], and that we want to leave them behind because it’s good for diversity, and incidentally that will save us an awful lot of money in the process,” he adds.

Tourism potential

With enough money and a bit of imagination, other retired rigs could enjoy useful second lives. In the Celebes Sea, off the coast of Malaysia, there’s one, called Seaventures Dive Rig, which has been turned into a tourist resort, with accommodation above the water and diving on the artificial reef below. More eccentric suggestions have included hotels, casinos, even high-security prisons.

In Saudi Arabia they are planning to go one step further, using a cluster of connected platforms to create a theme park, although it’s not clear whether the platforms will be newly constructed ones or refurbished existing ones

The lower infrastructure of some oil rigs, such as this one off the coast of California, have gained renewed purpose as artificial reefs and a haven for wildlife – and attraction for divers. Not everyone thinks the idea has environmental merit, however. 

Photograph by Kevin Griffin / Alamy

Back at Decom North Sea, Sam Long is more pragmatic. “There are some lovely concepts that come up against hard economic and technical realities,” he says.

He points out that, if platforms are left in place, those far out to sea in particular will pose logistical challenges. “Power, accommodation, life support, and a helicopter or boat to take people out there – the operational costs of all that in a marine environment are enormous,” he adds.

Meanwhile, in Weston-super-Mare, SeeMonster’s second life has proven to be tragically short-lived. As was always the plan, after closing on November 21st, dismantling began, its parts recycled.

Long, who like many in the UK’s energy industry lives in Aberdeenshire, hopes other decommissioned platforms will be offered new leases of life. “I’d love to see a few of them brought closer to the communities that supported them,” he says. “Even if they just decayed, it would raise awareness. It would reflect what is slowly but surely becoming the end of hydrocarbons.”


Explore Nat Geo

  • Animals
  • Environment
  • History & Culture
  • Science
  • Travel
  • Photography
  • Space
  • Adventure
  • Video

About us


  • Magazines
  • Disney+

Follow us

Copyright © 1996-2015 National Geographic Society. Copyright © 2015-2024 National Geographic Partners, LLC. All rights reserved