A team of EU-funded researchers co-ordinated by the UK have developed an innovative aluminium-based coating that provides better, more environmentally friendly protection to offshore energy installations. The coating is now being commercialised.

Whether from oil rigs, wave and tidal energy converters or wind farms, many energy needs are met by offshore sources which face harsh conditions and extreme environments. The challenges include paint degradation by UV radiation, seawater corrosion and high wind speeds which translate into a limited lifespan for the expensive structures.

Researcher Henry Begg of the EU-funded ACORN project commented:

“Steel structures in marine environments are subject to many forms of degradation, two of the most problematic being corrosion and biofouling.”  

“Although coatings to protect against such conditions exist within the shipping industry, where ships can be periodically dry-docked for maintenance, offshore structures are required to be moored in the water for extended periods of time and without ongoing preventative maintenance.”

To rectify this structural issue, Begg and the ACORN project team have developed an innovative protective coating that extends the lifetime of marine structures. The durable, non-paint solution can work on an array of offshore steel structures used for the production of renewable energy, including wind turbine foundations and wave or tidal energy devices, as well as conventional offshore infrastructures (docks, buoys, oil/gas rigs, etc.).

When the new coating is used, not only do the structures enjoy an extended and virtually maintenance-free lifespan of over 20 years, the need for supplementary (and costly) cathodic protection is also reduced – or even avoided. As a result, the project is boosting the competitiveness of the industry and helping to facilitate widespread roll-out of additional offshore technologies.

The eco-friendly anti-fouling substances were specifically chosen for their performance, commercial availability and regulatory approval for use in EU waters. In order to ensure the anti-fouling carriers were capable of withstanding the offshore conditions, researchers also evaluated their resistance to seawater corrosion, UV radiation damage and settlement of fouling organisms, with a particular focus on barnacle colonisation.

“Barnacles represent one of the most damaging biofouling species and can block a structure’s key access points, cut through protective paints and promote the settlement of further marine fouling organisms,” explained Begg. “We ultimately chose TSA because of its excellent track record in the oil and gas sector for providing long-term corrosion protection. Not only does it corrode at a very slow and predictable rate, unlike paints, it also provides local ‘sacrificial’ protection that protects the steel substrate even if the coating is damaged.”

With the ACORN project’s solutions now in the commercialisation phase, researchers are confident that their work will provide the market with an environmentally safe solution.

“As global energy demands shift, renewable energies will likely see the construction of more offshore energy installations over the next decades,” Begg continued. “Having these installations protected with the coatings developed by the ACORN project helps ensure that the production of sustainable energy is itself sustainable.”

Other countries taking part in the ACORN Project, with the UK acting as co-ordinator, are Spain, Sweden, Denmark and the Netherlands. Total costs of the project were  € 1,342,124 which includes an EU contribution of €1,036,000.