TECH

Study identifies potential savings in material requirements for wind energy expansion

For their analysis, the researchers reconstructed the development of Germany’s wind turbine fleet since 1988 and modelled various scenarios for its future development up to 2050. Among other things, they examined the material requirements for concrete, steel, copper, aluminium, polymers and composite materials. The study makes it clear that the further expansion of wind energy is associated with a considerable demand for materials. At the same time, the results show that the specific design of repowering measures is crucial for resource efficiency. In particular, the reuse of foundations, infrastructure components and other plant parts can significantly reduce material requirements.

The study analyses material flows and resource efficiency in the wind energy sector. Against the backdrop of wind energy expansion targets, it examines how future expansion can be organised in a way that conserves resources as much as possible. In doing so, it provides a scientific basis for assessing material requirements and potential savings in relation to wind turbines.

“Our aim was to systematically examine the material requirements of different expansion and repowering pathways and to highlight potential for material savings,” emphasises Christoph Helbig, Professor of Ecological Resource Technology and co-author of the study. “The results show that reuse strategies can be an important lever for combining resource efficiency with expansion targets.” The recycling of the wind turbines after their use was not part of this assessment.

In public debate, reference is often made to the absolute quantities of materials required for the construction and refurbishment of wind turbines. The study confirms that wind turbines consist of significant quantities of various raw materials and that their expansion requires corresponding resources. However, the key scientific finding of the study does not lie solely in quantifying these material requirements. Rather, a key finding concerns the potential to reduce future resource consumption through appropriate repowering strategies. 

Repowering refers to the replacement of older wind turbines with modern, more powerful ones. In the repowering scenario, in which the foundations, towers, and parts of the wind farm infrastructure are reused, the demand for concrete for onshore wind expansion is reduced by 14%, steel by 10%, and copper by 7% compared to a repowering scenario without reuse. For German offshore wind farms, cumulative copper demand would fall by 11% in the repowering scenario with reuse of the infrastructure. The analysis shows that, in particular, approaches to reusing foundations and infrastructure components can enable substantial material savings.

The researchers view their work as a contribution to a fact-based assessment of resource issues in the energy sector. Material requirements, the availability of raw materials, reuse and the circular economy are becoming increasingly important as the energy system undergoes transformation. The study provides a quantitative basis for this and highlights the options available for reducing resource use in the wind energy sector.

The University of Bayreuth points out that no blanket conclusions for or against a particular energy technology can be drawn from the study’s findings. Rather, the study provides scientific insights into how material flows are developing and what options are available for improving resource efficiency.

North Sea wind farm expansion may shift rain offshore, simulations suggest...Offshore wind farms are a key pillar of the energy transition. The European Union plans to expand offshore wind capacity in the North Sea by 2050. A new study by the Helmholtz-Zentrum Hereon indicates that a very extensive expansion could influence regional precipitation patterns: While precipitation over the sea could increase, it could decrease in coastal regions.

The research provides comprehensive insights into the potential regional climate impacts of future offshore wind farms, which the researchers emphasize must always be planned in harmony with the environment.

Researchers at Hereon's Institute of Coastal Systems—Analysis and Modeling used the high-resolution regional climate model COSMO-CLM to simulate various technical offshore wind energy expansion scenarios. The simulations were based on weather data covering the period from 2008 to 2017.

By analyzing an entire decade, the researchers were able to derive mean atmospheric dynamics across a wide range of weather conditions while reducing the influence of year-to-year variability. This approach allows potential long-term effects to be identified more robustly. The simulations included both existing and potential future offshore wind farm areas in the North Sea and Baltic Sea.

The researchers also considered the effects of wind turbines on wind speed, atmospheric mixing and moisture transport. Their aim was to gain a better understanding of the fundamental atmospheric processes that could be triggered by large offshore wind farm clusters. "Our work helps ensure that the further expansion of offshore wind energy in Europe can be aligned with the requirements of climate protection, environmental protection and coastal management," says Dr. Naveed Akhtar, lead author of the study.

A deliberately extreme expansion scenario...The scenario simulated in the study represents a purely technical expansion pathway that exceeds the European Union's current offshore wind deployment targets. It includes all designated areas in the North Sea and Baltic Sea that have been identified for potential offshore wind energy development. For these areas, the researchers assumed maximum deployment, resulting in an installed capacity that would substantially exceed the currently discussed target of 300 GW by 2050.

The researchers deliberately chose this scenario to make potential climate effects clearly detectable and estimate their magnitude. The rationale is that considerable uncertainty remains regarding which areas will ultimately be developed and how political targets may evolve in the future.

Precipitation patterns change...The results show that a large-scale expansion of offshore wind energy could lead to increased precipitation over offshore wind farm areas, while precipitation in adjacent coastal regions could decrease. The underlying mechanism is that wind turbines extract part of the wind's kinetic energy and simultaneously increase atmospheric turbulence.

Downstream of the turbines, strong variations in air movement enhance the exchange between different layers of the atmosphere. As a result, moist air can rise, cool and condense, leading to cloud formation and precipitation over the wind farms.

At the same time, the transport of moisture toward the coast is altered. If air masses release a greater share of their moisture as precipitation over offshore wind farm areas, less moisture remains available for precipitation in coastal regions. For parts of Denmark, Germany, the Netherlands and the United Kingdom, the simulations indicate potential reductions in coastal precipitation of up to 15%.

Long-term weather statistics rather than individual weather events...These findings can support sustainable maritime spatial planning and strengthen cross-border cooperation in the North Sea and Baltic Sea region. Previous studies by Hereon have shown that factors such as the size, layout and spacing of wind turbines can have a significant influence on atmospheric effects.

Future research should investigate a range of expansion scenarios and analyze how parameters such as turbine density, wind farm size and spatial distribution affect the regional climate. In addition, the researchers plan to further explore the impacts of offshore wind farms on the ocean and marine ecosystems.

source: Ecological Resource Technology