By Catherine Leaf, Risktec Solutions Ltd., a TÜV Rheinland company
Though no longer in its infancy, the offshore wind sector is still in its formative years compared to oil and gas (O&G).
Having spent the last 30 to 40 years fabricating, installing and operating countless offshore assets, the focus now for O&G is decommissioning. This is a challenge the offshore wind industry will soon face for its early developments as they reach the end of their 25-year design life.
Completed O&G decommissioning campaigns have produced a wealth of learnings that wind developers would do well to consider from the design stage onward.
Decommissioning challenges in O&G
When most of today’s O&G infrastructure was deployed in the North Sea over three decades ago, there was little thought given to how the structures would eventually be removed. Shell’s Brent Field gravity-based structures are a well-known example of this, and the supermajor has spent a vast amount of time and money investigating how this can be addressed.
O&G decommissioning has to date primarily focused on recycling as much of the resulting waste as possible. While preferable to disposal, this isn’t fully aligned with the circular economy, where reuse is optimal. Reusing O&G assets poses several challenges, including their age and the loss of technical knowledge as assets change ownership over time.
At its core, decommissioning is essentially a waste management project. However, this is not always recognized within the O&G sector, where greater focus is commonly given to offshore engineering activities, including in the contracts awarded.
Applying lessons to offshore wind: a question of design
Avoiding the same issues necessitates the offshore wind industry prioritizing sustainable decommissioning practices, particularly regarding waste management. The circular economy should be front and center of developers’ minds from the off.
Winds farms should be designed to maximize asset reuse at end of life. The ideal approach would be to reuse entire assets where possible, followed by partial reuse or repurposing of individual components. Recycling should only be considered as a last resort once all other options have been exhausted.
Get ahead of the game
By planning backward from the decommissioning phase, offshore wind farm designs can minimize waste throughout the project's life cycle. During construction, methods that allow the removal, reuse and repair of assets should be prioritized. In the operation and maintenance phases, practices should be reviewed to ensure components are repaired or repurposed, rather than simply replaced and scrapped.
Equally important is maintaining detailed records of maintenance to prevent knowledge loss. At the end of a wind farm’s life, decommissioning should aim to minimize waste by reusing as many assets and components as possible. This must be underpinned by robust contracts that amplify the importance of waste management and clearly define the responsibilities of all stakeholders involved.
Practical steps to maximize resource reuse
Creating an overarching waste management plan, developed alongside the wind farm’s design and detailing the types and quantities of waste expected to be generated throughout its life cycle, is a key step in applying this framework.
In the UK government’s Offshore Wind Leasing Round 5, focused on floating wind in the Celtic Sea, bidders are encouraged to demonstrate "ambitious" sustainability goals. An overarching waste management plan would be an excellent tool to showcase this commitment.
As more wind farms are built, the industry will gather increasing amounts of valuable data. It is crucial to collect, analyze and feed this information back into the design of future wind developments. By learning from past projects, the industry can continuously refine and improve waste management strategies, ultimately driving more sustainable renewable energy developments.
