The shape of blades to come

A major €4 million research collaboration of 10 European partners is leading the development of seven novel offshore wind turbine blade technologies, which together, it is hoped, will lower the levelised cost of electricity (LCOE) of offshore wind by as much as 4.7%.

The Offshore Demonstration Blade (ODB) project is supporting the research, development and demonstration of wind turbine blade innovations, including aerodynamic and structural enhancements, blade monitoring systems and blade erosion protection solutions. These products will be developed and retrofitted to the Offshore Renewable Energy (ORE) Catapult’s 7MW Levenmouth demonstration turbine in Scotland for demonstration purposes. The innovations will then be ready for deployment on existing or new offshore turbines.

The two-year Demowind-funded project will be co-ordinated by the UK’s ORE Catapult Development Services (ODSL), and involve significant organisations in wind turbine innovation including CENER, Bladena, TNO, Aerox, Siemens Gamesa Renewable Energy, Total Wind, Dansk IngeniørService A/S (DIS), the Technical University of Denmark (DTU) and the Cardenal Herrera University (CEU) in Spain.

Operations and maintenance costs represent almost a quarter of the total LCOE of an offshore wind turbine, with rotor operations and maintenance, specifically blade erosion and blade structural integrity, representing a large share of these costs. Therefore, improving the performance and operational lifetime of turbine blades will have a direct impact in lowering LCOE.

Chris Hill, Operational Performance director at ORE Catapult, said “Having a dedicated platform on which to demonstrate these technologies, the Levenmouth demonstration turbine, will improve our understanding of how they operate in real- world conditions and the impact they will have on blade performance, operations and cost of energy.”

Visions of the future

Based on its own research work currently underway, ORE Catapult has its own ideas about how wind turbines of the future will develop. In a pamphlet that sets out its vision of the likely shape of WTGs to come it talks about an explosion of innovation in the UK that will see an army of autonomous robots service giant offshore wind turbines with tens of rotors, while parachute-shaped kites will transform how we think about wind turbines.

Pioneering designs in WTGs and storage could see offshore wind meeting a third of the UK’s electricity demand within 12 years, making it the backbone of the country’s energy mix.

Dr Stephen Wyatt, Research and Innovation director at ORE Catapult, commented: “Technical capability has come on leaps and bounds in recent years and if we look back 12 years to 2006, very few people would have foreseen how far we’ve come with turbine technology and storage, for example.

“Whatever the future holds, the work taking place right here in the UK will have a pivotal impact not just on how we generate energy, but on how we view offshore renewables.”

Trends we are likely to see growing over the next two to three decades include robots and drones, with automated motherships carrying armies of droids to hazardous offshore locations, where they will carry out maintenance and basic repairs more cheaply than ever before.

Turbines will become bigger, but challenges faced by scale and weight will mean more innovative designs will come to the fore, including multi-rotor designs and vertical axis turbines. Issues faced by intermittency will also be a thing of the past, with energy storage technology maturing within 12 years to become a key part of the energy mix.

Dr Wyatt added: “What we cannot predict is the disruptive innovations that could drastically alter the course of offshore wind development, but our representative testing and demonstration facilities mean these innovators have no better place in the world to bring forward these innovations than in the UK.”

ORE Catapult predicts that by 2030, floating wind farms will become the norm, with significantly larger turbines generating over 15 MWe, compared to the 7 MW drive trains today. Blades themselves will be larger, but novel materials will reduce the cost of the repairs and maintenance. Drones and AI-driven monitoring systems will be commonplace. And soon to be tested on real turbines at ORE’s testing facilities in Blyth, Bladebug is an innovative micro-SME blade crawler. This robotic crawler could significantly reduce the cost and risk of blade maintenance activities – and will be able to operate even when the wind is too strong for flying drones.

By 2040, turbines will be accompanied by a new type of technology. There will be extensive roll out of a floating kite power generator. Because the kites are lightweight, the systems use less material than conventional wind technology so produce energy at a lower cost. And those turbines will benefit from less expensive generators. Expensive rare-earth magnets will be replaced by cheap, abundantly available ferrite magnets thanks to an innovative generator developed by GreenSpur Renewables.

To 2050, wind turbines will continue to grow in size, with 200 m blades being the norm in single-rotor designs. Because of their size, these blades will use an entirely new construction method, with flexible blade structures used to reduce the likelihood of breakage. Secondary rotors could start to be used on the tip of blades – where because of their high speed they will generate even more power from every gust.

Vertical axis turbines, still in their infancy, will start to address the challenges current designs pose in weight, with larger traditional blades becoming less feasible on a tower structure. These vertical axis blades will have numerous other benefits, such as being able to generate power no matter which direction the wind is blowing in.

This technology will benefit from the MagLev technology currently used for metro trains in Japan. Used in tandem with vertical axis turbines, this will reduce the friction between the turbine and the blade to zero, allowing greater yield by allowing generation with even less wind.

The rise of the robots will continue with the introduction of the Mothership. These are fully autonomous boats that can transfer crew to turbines, along with more advanced robots and drones, acting both as charging stations and data-hubs.