Over two years ago BUMAX® 88 fasteners were successfully used on the 1MW HydroQuest tidal turbine in Paimpol-Bréhat, France. After two years of operation at 30m depth, the fasteners are showing no traces of corrosion or galling.
Installed off the coast of Brittany in north-west France and capable of providing Europe with reliable renewable energy, the tidal turbine prototype was designed by HydroQuest, a French turbine technology developer of vertical axis turbines. Once deisgned, the turbine needed a maintenance free fastener solution to minimise operation costs over a lifespan of 20 years. Besides durability, the fasteners also had to be easy to install.
Tests of the mechanical properties including both strength and ductility of the bolts conducted by BUMAX® after the pilot project, showed the turbine fasteners had maintained their properties. “No issues were found related to bolting during this project, and our team didn’t have any issues with galling during disassembly,” says Raphaël Coquet, project director at HydroQuest. “These lessons give us positive learnings the long-term deployments, and we are confident in manufacturing our future turbines with BUMAX® bolts.”
The BUMAX® 88 grade was selected for its high molybdenum content and high pitting resistance equivalent number (PREN) that indicates a high resistance to localised pitting corrosion. This particular grade of 316L stainless steel has an excellent track record when used for BUMAX® fasteners in demanding marine applications, to provide durable and maintenance free fastener solutions.
Following the pilot project, HydroQuest is integrating the learnings from the pilot to design the next generation of the tidal turbine, which will also use BUMAX® 88 bolts. Seven of these 2.5MW tidal turbines will be deployed at the FLOWATT project at the Raz Blanchard site off the coast of Normandy with a design lifespan of 20 years. The commissioning of FLOWATT is planned for 2025 with the construction of the tidal turbines starting in 2023.
Having spent a decade in the fastener industry experiencing every facet – from steel mills, fastener manufacturers, wholesalers, distributors, as well as machinery builders and plating + coating companies, Claire has developed an in-depth knowledge of all things fasteners.
Alongside visiting numerous companies, exhibitions and conferences around the world, Claire has also interviewed high profile figures – focusing on key topics impacting the sector and making sure readers stay up to date with the latest developments within the industry.