Aker Solutions has toppled the decommissioned Gyda field’s topside in reportedly the largest-ever demolition of its kind.
Mountains of recovered steel and other precious resources are about to join the circular economy as low-carbon equivalents.
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.
Emissions-tracking tools suggest recycled steel is 70% less carbon-intensive than the ore-derived variety. Recycled aluminum is 92% less CO2-intensive. Recovered copper, 65% cleaner, according to data from Stena Recycling.
Citing info from EcoInvent, Aker Solutions’ own environmental expert, Marcin Pazdro, said 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.
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, methods that are cost-effective and require engineering inputs, experience and secure space.
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.
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.
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.
With its jacket (substructure) and topside (superstructure), Gyda once weighed in at around 29,000 tons. Aker Solutions built the jacket at Verdal and then recycled its 11,000 tons.
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 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 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.”