Wind turbines are essential for achieving decarbonisation and increasing energy security. The UK plans to reach up to 50GW of offshore wind deployment by 2030. This target is driving demand for components and materials required to produce wind turbines, and technology metals such as rare earth elements (REE) are playing a major role. REE such as neodymium, prasedymium, dysprosium and terbium are used in the production of neodymium iron boron magnet (NdFeB). They are used to manufacture powerful generators that come in a range of technical configurations. At the same time, several installed wind turbines are expected to reach their decomissioning stage soon, and could therefore provide a source of secondary REE.
Components and metals in wind turbines
Facts about supply and demand
Based upon National Grid Future Energy Strategy Report (2021) the expectation in the most aggressive leading the way scenario is expecting an increase from currently 89 TWh to 645 TWh by 2050, which will require a significant inflow of the necessary materials and components.
Todays demand for wind turbines
Wind power accounted for 29% of the UK's total electricity generation in 2021, with 64 TWh stemming from onshore (29 TWh) and from offshore (35 TWh) wind turbines.
With total wind turbine generation power of 78,342,126 MWh/p.a., the current installed base of wind turbines amounts to 8,873 onshore installations and 2,652 offshore installations. Figure 2 is a map of UK operational wind farms with a capacity above 0.5 GW, while Figure 3 is an overview of the currently installed base and its development over time. In 2022, the cumulative installed capacity was 28,759 MW.
The installed base represents a significant material stock at known location and quantities, which is an important asset for the UK and allows potential component and material harvesting post usage.
Looking at the ramp-up at the beginning of the change of the millenium, we are currently observing the first wind turbines to reach their orignially designed end-of-use time of about 20 years.
This is likely to increase in the near future, the need for actively entering into CE revalorisation phases for these wind turbines comprising
- prolongation of usage by refurbishment and revamping etc, including potential upgrades
- improving material recovery by dedicated decommissioning including component harvesting and material recycling
Future demand for wind turbines
According to the National Grid*, the UK will have 224.65 TWh offshore and 85.40 TWh onshore wind power electricity generation and 50.95 GW offshore and 30.77 GW onshore installed capacity in 2030. In 2050, the expected contribution of wind turbines to the energy mix is estimated to reach 549.8 TWh; out of which onshore is likely to provide 151.5TWh and offshore 398.3 TWh. With an expected 133.8 GW of total installed wind turbine capacity (89.06 GW offshore and 44.77 GW onshore), the number of wind turbine installations will continue to grow over the next 27 years.
*Note: Leading the Way scenario, Future Energy Scenarios 2022
Futher reading
Bill of materials of wind turbines
Wind turbines are structures with well defined component structures and a relative few technologies, which allow to translate the stock of windturbines into material compositions leveraging typical bill of material (bom) structures.
Most of the wind turbines in the UK are still operating. The overall lifetime of the wind turbines is expected to be between 20 years and 30 years. Wind power technology transformations, expanding the size of wind turbines to increase efficiency, led to the change of using different types of generators and the increasing amount of materials used in wind turbines.
About Rare earth permanent magnets (PMs)
Evolution of wind turbine size
The size of wind turbines in terms of rotor diameter, hub height and rated power has increased dramatically in the past two decades. Figure 5 shows UK offshore wind turbine size evolution from 2002 (2MW, 93m) to 2022 to 2023 (12MW, 236m). Figures 6 and 7 show the number of newly installed wind turbines and the average power rating of onshore and offshore wind turbines between 2017 and 2022. The onshore wind turbines had an average power rating of 4.3 MW, while the offshore wind turbines had an average power rating of 8.6 MW in 2022.
Types of generators
The generator is the key component of wind turbines. There are different types of generators. The transmission is typically classified into direct-drive and gearbox mechanisms with different machine types, rotors and speeds. Leveraging a classification into different sub-technologies with typically dedicated material and component configurations provides an opportunity to estimate future release rates and the current composition of the material stock in use.
To provide a more comprehensive classification, the types of wind turbines can be classified based on the drive train configuration, speed, and onshore and offshore application. In Figure 4, the onshore applications are in green, the offshore applications are in dark blue, and those generators used in both onshore and offshore applications are in purple.
Conventional generators (e.g., SCIG and WRIG) developed before PMSG do not include permanent magnets, and tend to use in onshore wind turbines rather than offshore installations. The black dashed line represents the types of generators that are widely adopted in the past decade, but no longer dominate the market. DFIG currently has a higher market share but is only used for less than 3MW capacity, while the penetration rate of PMSG has continuously been increasing due to its better energy efficiency. PMSG is currently the main R&D focus of all generator types regarding reducing cost and REE content while increasing turbine capacity and efficiency. Direct drives based on High-Temperature Superconductors (HTS) are a new type of generator at the R&D stage and could potentially be used in the future to reduce the use of REE.
Translation into material stocks
A typical wind turbine consists roughly out of
- 234,500 - 413,000 kg/MW of concrete
- 107,000 - 132,000 kg/MW of steel
- 950 - 5,000 kg/MW of copper
- 500 - 1,600 kg/MW of Aluminium
- 12 - 180 kg/MW of Neodymium (Nd)
- 2 - 17 kg/MW of Dysprosium (Dy)
- 0 - 35 kg/MW of Praseodymium (Pr)
- 0 - 7 kg/MW of Terbium (Tb)
Rare Earth Elements embedded in the magnets, which are largely installed in the generator but also the motors for navigating the pitch and dirction of the blades, while small in volume are a crictial enabler to deliver the required reliability and performance of the wind turbine.
Futher reading
Serrano-González, J., and Lacal-Arántegui, R. (2016) Technological evolution of onshore wind turbines—a market-based analysis. Wind Energ., 19: 2171-2187. https://onlinelibrary.wiley.com/doi/10.1002/we.1974
Carrara, S., Alves Dias, P., Plazzotta, B. and Pavel, C., Raw materials demand for wind and solar PV technologies in the transition towards a decarbonised energy system, EUR 30095 EN, Publications Office of the European Union, Luxembourg, 2020, ISBN 978-92-76-16225-4, doi:10.2760/160859, JRC119941. https://publications.jrc.ec.europa.eu/repository/handle/JRC119941
Offshore Renewable Energy Catapult https://ore.catapult.org.uk/
Contact
For questions regarding the project please contact Dr Evi Petavratzi.