There are several recycling challenges that we as an industry need to overcome to be truly sustainable. As a manufacturer, BGB has a responsibility to ensure that our products leave a minimal impact on our planet. From the late 90s to early 2000s the wind industry started to industrialise its components both in volume and cost out to enable it to compete with conventional energy sources and ultimately become subsidy free. This manifested in the design decisions and manufacturing practices of the time. We made our slip rings from a bronze alloy able to deal with the power requirements of 2-3MW platforms and insulated them with thermoplastic. Our entire factory from front to back was continually optimised over many years to reduce the cost of these components to increase the speed and volume of production. Twenty years later there are now over 60,000 of these slip rings out in the field in all seven continents.
In response to this problem, we commissioned a continuous improvement study in partnership with Vattenfall who operate a local wind farm in Leicestershire of 11 x V90-2MW wind turbines. We did this to understand what processes we could develop to recover, reuse and repair these components. Our repair solution looks to improve the contact surface on the rings whilst keeping it within tolerance for good brush alignment and cooling performance. BGB engaged with Vattenfall tounderstand their maintenance practices and wear rates and to perform some explorative testing some recently failed units. Andrew Claridge, O&M Manager explains: “We partnered with BGB because of their expertise, industry knowledge and personal approach. When they mentioned the opportunity to work together on a repair and recycling project we jumped at the chance. Sustainability and environmental performance are very important here at Vattenfall as we hope to be carbon free within one generation.” In the event of an irreparable unit, we developed a new process to recover the hubs from the slip rings, separate out the metals and the thermoplastics. The hubs and terminal plates could now be reused in new slip rings, reducing the cost and new metal required. The improvement in material recovery can be seen in the graph.
Implementing repair and recycling practices postproduction is sub-optimal. Today BGB applies circular economic principles into its design processes. Rather than designing purely for cost, we work with like-minded partners before the specification stage to factor in the complete life of the component within the wind turbine with a focus on serviceability. By developing slip rings in a modular way, they can be disassembled in the opposite order that they were assembled, making all the components accessible for repair and replacement. This means that all the structural and insulative elements can be accessed, inspected, cleaned, and preserved and only the wearing components are changed as required. This reduces the future waste impact that our manufacturing and servicing practices have on the planet and its resources. To ensure that quality is maintained we ensure that everything is tested prior to sending back into service, we use OE parts wherever possible.
The Happy Customer
“We are very pleased with this innovative approach in finding a better way to recycle and reuse these components.” Vattenfall
BGB offers multi-brand slip ring servicing and repair to reduce O&M costs for windturbine operators as well as reducing their waste stream from generator brushes and other materials. Vattenfall are one of Europe’s largest producers and retailers of electricity and heat. Vattenfall AB, is 100% owned by the Swedish state, and its headquarters are in Solna, Sweden.