Aker Solutions to sort, recycle 18,000t topside
October 23, 2023
If decommissioned the right way, offshore energy infrastructure like the Gyda topsides offer an enormous resource of valuable materials — including steel prized by builders. Recycling and reusing metals offers a lower-emissions alternative to metal derived directly from ore and shipped.
In fact, emissions-tracking tools suggest recycled steel is 70-percent less carbon-intensive than the ore-derived variety. Recycled aluminum is 92-percent less CO2-intensive. Recovered copper … 65 percent cleaner, according to data from Stena Recycling.
Citing info from EcoInvent, Aker Solutions own environmental expert, Marcin Pazdro, says returning 18,000 tons of steel to the circular economy would cut carbon emissions by 26,000t to 30,000t, depending on the steel production process used as benchmark.
Before recycling, a giant steel structure has to be decommissioned, hauled to shore and demolished. Aker Solutions has been decommissioning and recovering offshore oil-and-gas infrastructure for over 25 years.
Toppling the Gyda topsides to recover 18,000 tons of steel and other valuable metals was the latest in a series of controlled demolitions for offshore energy clients. It just happened to be the largest operation of its kind, where precision demolitions and pull force took down a topside.
“The operation was well-planned and executed — a big milestone and team achievement,” said head of Aker Solutions Decommissioning, Thomas Nygård.
“Projects like these are important for us, they're important to our clients and they let us return value to the circular economy,” Nygård says.
About 10,000 platforms now in operation worldwide will one day have to be decommissioned. Many of these structures are in the North Sea, from which Aker Solutions has secured a pipeline of orders for structural teardowns.
Circular economics
With the energy transition underway and materials costs rising, the worldwide decommissioning and recycling of offshore infrastructure takes on new importance. The demolition of Gyda — which will be 98-percent recycled — will provide valuable building materials for new energy projects.
“However you look at it, the recycled steel and other materials recovered from Gyda would represent a sizeable contribution to Aker Solutions or our customers’ own material needs going forward,” Pazdro says.
As part of its decommissioning offering, Aker Solutions prepares a Second Life Report detailing the recoverable raw materials made available from the recovered material in platform jackets, topsides and other retired energy infrastructure. For operators, the Report reveals a treasure trove of reusable resources: aluminum for bridges; steel for girders; reusable generators, pumps, fire-suppressors and more.
Decommissioning
With its jacket (substructure) and topside (superstructure), Gyda once weighed in at around 29,000t. Aker Solutions built the jacket at Verdal and then recycled its 11,000tons. The topside was the largest ever toppled using explosives and pulling power — a cost-effective technique requiring engineering inputs, experience and secure space.
Once felled, large cutting machines and a giant, stationary shears make the dismantling operation efficient and safe. The chopped-up steel structures and cuttings are then sorted and shipped for remelting and possible use as additives.
The Gyda topside
The Repsol-operated Gyda oilfield in the southern North Sea was onstream between 1990 and its shut-down in the fall of 2021. The following summer, its topside was transported to Aker Solutions’ Stord yard in western Norway by the world’s largest construction vessel, Allseas’ Pioneering Spirit. Since then, Aker Solutions has safely dismantled and recycled Gyda’s drilling and flare towers, along with associated waste.
The Gyda topside
The Repsol-operated Gyda oilfield in the southern North Sea was onstream between 1990 and its shut-down in the fall of 2021. The following summer, its topside was transported to Aker Solutions’ Stord yard in western Norway by the world’s largest construction vessel, Allseas’ Pioneering Spirit. Since then, Aker Solutions has safely dismantled and recycled Gyda’s drilling and flare towers, along with associated waste.