Thu, 05 September, 2019
The offshore wind industry has flourished amidst declining use of fossil fuels and rising concerns about climate change. Despite the unprecedented pace of cost reduction seen over the past decade, challenges remain in protecting offshore wind infrastructure from the harsh offshore environment, which can result in high maintenance costs and reduced component lifetimes. Unsurprisingly, whether in splash, tidal or subsea service, offshore wind turbine foundations are under constant threat from the seawater corrosion and measures must be taken to ensure long-term structural integrity. Conventional corrosion protection relies on organic paints and galvanic anodes, which can be costly to both manufacture and install. Coating techniques that can replace paint and anodes entirely offer prospective cost savings by removing bottlenecks in the fabrication and installation of wind turbine foundations.
Following on from the success of the CROWN (Cost Reduction for Offshore Wind Now) project, recognised for its strength and outstanding nature at the Rushlight Awards 2017/18, CROWN 2 explores innovations to change the way offshore wind foundations are protected from corrosion.
CROWN 2: where do we go next?
Thermally sprayed aluminium (TSA) coatings, used for more than 40 years to protect offshore oil and gas platforms from seawater corrosion, have demonstrated cross-sector applicability and could reliably and cost-effectively extend the life of offshore wind turbine foundations to >40 years. In particular, the project is:
- Performing in-situ corrosion trials in differing corrosion environments (low and high salinity) to validate long-term performance in real-world conditions.
- Undertaking quantitative electrochemical studies into TSA performance.
- Investigating high visibility top coats and the interface between epoxy coatings and TSA.
- Designing guidelines and numerical models to aid developers and fabricators in both manufacture and certification.
- Working towards implementation of mechanised spray systems at large scale.
A promising first year !
The CROWN consortium demonstrates promising preliminary results after the project’s first year. “The project offers unique know-how and experience to be at the forefront of delivering cost-effective TSA coating technology for wind farm projects”, says Henry Begg, Section Manager, Surface Engineering TWI and coordinator of CROWN 2 project. “The development of design guidelines and numerical modelling approaches will ensure that the technology can be adopted rapidly and implemented safely and efficiently”.
Retrieval and analysis of on location test samples from the North and Baltic seas following exposure for over a year, exhibit promising results. The project is also focussing on TSA-paint interfacial deployment case assessments to review use of TSA coating of monopile foundations in conjunction with high visibility, yellow paint systems on the transition piece.
The project recently completed a comprehensive review of the key standards covering the deployment of TSA coatings for the protection of offshore structures and highlighted areas of poor provision. This study will inform the final project output: a comprehensive set of guidelines outlining best practice in the design and manufacture of foundations employing TSA as the primary corrosion protection. The CROWN 2 project is generating new research data, developing design guidelines and validating long-term performance that will provide designers and developers with the confidence to specify TSA in new-build projects.
The project is funded by Innovate UK grant number 104363.