German Wind Research Articles

Concentration versus diversification: A spatial deployment approach to improve the economics of wind power

Previous studies on the economics of onshore wind parks in Germany found that geographic diversification results in minor system costs savings (Pfluger et al., 2017a). Furthermore, such diversification does not necessarily result in higher market values (Eising et al., 2020) or better merchant profitability (Klie and Madlener, 2022). Therefore, the question arises whether an alternative allocation (i.e. concentration rather than diversification) of the German wind park fleet is more economical. In this paper, we compare the future (2030) market values, subsidy needs and total system costs (excl. intra-national grid costs due to congestion, redispatch and curtailment) of a more concentrated versus a more diversified allocation of onshore wind turbines in Germany. The results show that a concentration of turbines, in areas where the gap between market values and levelized costs of electricity is smallest (i.e. Northern Germany), is more beneficial in terms of subsidy need and system costs (ignoring congestion, redispatch and curtailment). The analysis further shows that these areas are also more beneficial in terms of market values, when using system-friendly turbine configurations selected based on the same approach. To incentivize such a selection of areas and turbine configurations based on minimal gaps between market values and levelized costs an alternative renewables support scheme is presented, which favors such minimal gaps in its auctioning process.

Fuelling the Energy Transition: the Effect of German Wind and PV Electricity Infeed on TTF Gas Prices

Fuelling the Energy Transition: the Effect of German Wind and PV Electricity Infeed on TTF Gas Prices

Crowdsourcing social acceptance: Why, when and how project developers offer citizens to co-invest in wind power

Citizen co-investment in wind energy projects has recently received a lot of attention among scholars and policymakers as a way to finance renewable energy projects and increase community acceptance of these projects. Citizen co-investment refers to the process by which members of the local community can financially participate in renewable energy projects prior to or shortly after construction. While previous research has often been cross-sectional and focused on the preferences of citizen-investors, this paper focuses on the perspective of project developers and asks why, when and how they offer citizens the opportunity to co-invest in wind farms. The work is based on the analysis of fourteen in-depth interviews with a sample of experienced German wind energy developers. The analysis shows that the decision to offer co-investment is driven by citizen demand and local stakeholder preferences, rather than financial needs. We shed light on how experienced developers deal with key trade-offs in terms of the timing of their offering and the choice of capital structure. As a result, we offer a number of testable propositions for further research on the nuanced relationship between citizen co-investment and social acceptance and derive recommendations for policymakers.

Trade-offs in German wind energy expansion: building bridges between different interests, values and priorities

BackgroundTo achieve climate targets, a transition to low-carbon energy production is necessary. However, conflicts between different interests, values and priorities, particularly at the community level, can constrain this transition. This paper aims to analyze lines of conflict and opportunities to build bridges between conflicting interests in the expansion of wind energy in Germany at the local level, to achieve successful implementation of wind energy projects.ResultsOur analysis of four cases of local-level wind energy projects in Germany shows that limited local options for action reinforce the need for local actors to maximize the benefits of energy transition projects. In addition to the conflict over scarce space, the lines of conflict at the local level run primarily along the dimensions of costs and benefits, winners and losers. Real or perceived procedural and distributive injustices had the potential to fuel resistance to wind energy projects in the analyzed cases. However, wind energy projects were successfully implemented despite the presence of local opposition.ConclusionsThe results show that, by integrating procedural and distributive justice into the project planning and implementation and offering tailored solutions, community support for expansion of renewable energy projects can be enhanced. The paper advances the concept of societal ownership (“gesellschaftliche Trägerschaft”), which suggests the willingness of members of a community to tolerate decisions even when some conflicts related to the decision remain unresolved. Societal ownership is presented as an alternative to the concept of simple acceptance; it implies a more positive, more supportive community attitude, where members aim to address conflict as a normal aspect of decision making. Rather than sweeping alternative opinions aside, the community addresses alternative viewpoints, seeking to achieve greater procedural and distributive justice. In this way, a sense of societal ownership of a project can develop, enhancing its likelihood of success.

Computational fluid dynamics studies on wind turbine interactions with the turbulent local flow field influenced by complex topography and thermal stratification

Abstract. This paper shows the results of computational fluid dynamics (CFD) studies of turbulent flow fields and their effects on a wind turbine in complex terrain. As part of the WINSENT project, a research test site comprising four meteorological masts and two research wind turbines is currently being constructed in the Swabian Alps in southern Germany. This work is an essential part of the research of the southern German wind energy research cluster WindForS. The test site in complex terrain is characterised by a densely forested escarpment and a flat plateau downstream of the slope. The met masts and wind turbines are built on this plateau. In the first part, high-resolution delayed detached eddy simulations are performed to separately investigate the effects of the forested escarpment and of thermal stratification on the flow field and accordingly on the wind turbine. In the second part, both these effects are included for a real observed case in March 2021. There, unstable conditions prevailed and the forest showed low leaf area densities due to the winter conditions. It is shown that atmospheric turbulence, forests, orographies, and thermal stratification must be considered when assessing the impact on wind turbines in complex terrain. All of these effects influence the flow field both at the turbine position and in its wake. The wind speed at the test site is accelerated by up to 60 %, which could affect the annual energy production significantly. But otherwise turbulent structures of the forest wake cross the rotor plane temporarily and thereby affect the turbine inflow. Moreover, convective conditions and upward flows caused by the orography have an impact on the turbine's power output as inclined flows result in asymmetric torque distributions. The wind turbine wake and the forest wake mix further downstream, resulting in a faster decay of the turbine wake than in neutral conditions or without forest. The paper also describes how the turbulent flow in the wake changes in the presence of thermal stratification, which is evident in order to be able to numerically represent the flow-physical changes in the diurnal cycle well.

Knowledge generation and diffusion in the German wind energy industry

Abstract This paper shows that collaborative innovation projects (CIPs) are an important arena for both knowledge generation and its incorporation into the industrial knowledge base (IKB). By differentiating between the cultural-cognitive, normative, and regulative dimensions of technology generation and diffusion, we describe interdependencies between CIPs and IKBs. On the basis of three vignettes from the German wind energy industry, six interrelations (translation, imitation, structuring devices, consolidation, strategic closure, and strategic inertia) are identified on how CIPs contribute to IKBs.

Facing transition phase two: Analysing actor strategies in a stagnating acceleration phase

Energy transition processes are currently entering into a new phase which is characterised by the maturing of renewable energy technologies and the challenges of system integration and regulatory changes, in particular the introduction of tender schemes for onshore wind energy. In the German wind energy sector, these policy changes are resulting in a drop in build-out during a phase when acceleration rather than stagnation would be expected. Furthermore, several major wind actors are facing insolvency, instigating redundancies or deciding to relocate, increasing the level of uncertainty within the sector.This paper analyses how actors in the wind sector are reacting to the introduction of tender schemes and how their strategic activities are affecting the transition process. We analyse four strategies: geographical diversification, cooperation/mergers and acquisitions (M&A), business field diversification and market exit. Specifically, we analyse the reactions of project developers, turbine manufacturers, energy utilities and banks. We show that the strategies chosen by key wind energy actors may actually be slowing down the transition process rather than accelerating it. We argue that adopting an actor strategy perspective provides new insights for sustainability transition research while at the same time highlighting implications for public policy and strategic management.

Predictive Capability of WRF Cycling 3DVAR: LiDAR Assimilation at FINO1

In this study, we assess tentatively the predictive capability of the Weather Research and Forecasting (WRF) model and its Three-Dimensional Variational (3DVAR) system. We study the impact of LiDAR data assimilation on predictions of wind speed and direction. The simulation domain covers the German wind energy research platform FINO1 in the Southern North Sea, at which the LiDAR data were recorded. The results demonstrate the significance of applying the LiDAR Data Assimilation (DA) with a short assimilation interval (1-hour) to improve the wind prediction and the temporal and spatial representation of low level jet events, compared with an experiment without DA. Furthermore, we briefly examine the impacts of data assimilation cycle length on predictive performance of the DA system, and spatial variability of wind speed over the study area at a height of 250 m.

External auditory exostoses in wind-dependent water sports participants: German wind- and kitesurfers

PurposeCold water and wind are known to cause exostoses of the external auditory canal. Different prevalences in different sports have been described in the literature. The aim of this study was to investigate the prevalence of external auditory exostosis (EAE) and EAE severity in coastal German wind- and kitesurfers who are exposed to cold water and strong winds. Furthermore, influencing factors such as the total exposure time and frequency of activity as well as the correlations between symptoms and the severity of EAE were investigated.MethodsIn this retrospective cross-sectional study, German non-professional wind- and kitesurfers along the North and Baltic Sea coasts were recruited between September 2020 and November 2020. Each participant was interviewed about exposure time and otological symptoms and underwent bilateral video otoscopic examination to determine EAE severity.ResultsA total of 241 ears from 130 subjects were analysed. The prevalence of EAE was 75.1%. In 19.9% of the participants, severe EAE was found. Exposure time and the frequency of activity had significant effects on the severity of EAE. Compared to surfers, EAE growth seems to progress faster in wind- and kitesurfers. The number of symptoms requiring medical treatment increased when two-thirds of the external auditory canal was obstructed.ConclusionThe prevalence of EAE in wind- and kitesurfers is high. Total exposure time and the frequency of activity influence EAE growth. EAE growth occurs faster in wind- and kitesurfers than in surfers. The additional influence of wind and the evaporative cooling of the EAC are thought to be responsible. The results of this study should increase awareness of the dynamics of EAE among ENT specialists and improve patient counselling.

Modeling of the German Wind Power Production with High Spatiotemporal Resolution

Wind power has risen continuously over the last 20 years and covered almost 25% of the total German power provision in 2019. To investigate the effects and challenges of increasing wind power on energy systems, spatiotemporally disaggregated data on the electricity production from wind turbines are often required. The lack of freely accessible feed-in time series from onshore turbines, e.g., due to data protection regulations, makes it necessary to determine the power generation for a certain region and period with the help of numerical simulations using publicly available plant and weather data. For this, a new approach is used for the wind power model which utilizes a sixth-order polynomial for the specific power curve of a turbine. After model validation with measured data from a single wind turbine, the simulations are carried out for an ensemble of 25,835 onshore turbines to determine the German wind power production for 2016. The resulting hourly resolved data are aggregated into a time series with daily resolution and compared with measured feed-in data of entire Germany which show a high degree of agreement. Such electricity generation data from onshore turbines can be applied to optimize and monitor renewable power systems on various spatiotemporal scales.

Introducing a new approach for wind energy potential assessment under climate change at the wind turbine scale

An important aspect of planning the future expansion of wind energy is the consideration of changes in available wind resources due to climate change. In previous studies simulations of the future behavior of wind resources were derived from regional climate models at coarse spatial resolutions not suitable for wind energy potential assessment at the wind turbine scale. Thus, this study investigates the hypothesis that changes in future wind resources initiated by climate change will influence important aspects of small-scale wind resource assessment. A new approach is introduced that can be used to quantify the (1) spatial wind resource availability, (2) temporal wind resource availability, and (3) geographical complementarity under climate change at the wind turbine scale. The assessment of the future spatiotemporal variations in wind resources is based on an ensemble of near-surface (10 m) wind speed time series at a daily resolution for the period 1981–2099 from 35 different regional climate models. Using the highly resolved (horizontal resolution: 200 m × 200 m) Wind Speed-Wind Shear model, the near-surface wind speed time series were bias-corrected and extrapolated to a wind turbine hub height of 140 m at the sites of the current wind turbines in Germany. Bias correction was carried out by matching the quantile distributions from the regional climate models and the Wind Speed-Wind Shear model. Afterward, a power curve of a modern 3.45 MW wind turbine was applied to calculate daily capacity factors. The results indicate small long-term changes in the wind resource availability under the representative concentration pathways 4.5 and 8.5. It was found, that the influence of the interannual variability of the German wind resource exceeds the influence of climate change on the wind resource. The newly developed approach goes beyond previous wind resource assessments under climate change because it offers the opportunity for the spatially explicit investigation of different aspects of wind resource assessment which allows to develop more sophisticated wind energy expansion plans. Although the results are valid only for the study area, the proposed methodology is portable to any other region around the world.

Pulled or pushed? The spatial diffusion of wind energy between local demand and supply

Abstract This article contributes to and connects the literature on spatial innovation diffusion, entrepreneurship, and industry life-cycles by disentangling the relevance of local demand and supply in the adoption of wind energy production. More precisely, we evaluate the strength of local supply–push effects with those of local demand–pull over the course of the evolution of an industry and its main product evolution. By using Bayesian survival models with time-dependent data of wind turbine deployment and firm foundation for 402 German regions between the years 1970 and 2015, we show that the spatial evolution of the German wind energy industry was more strongly influenced by local demand–pull than local supply–push processes. New producers are found to emerge in proximity to existing local demand for wind turbines. No evidence was found for producers being able to create local demand for their products by pushing the adoption of the technology in their regions.

Concentration Versus Diversification: A Spatial Deployment Approach to Improve the Economics of Wind Power

Previous studies on the economics of onshore wind parks in Germany found that geographic diversifi-cation results in no significant system costs savings. Furthermore, such diversification does not neces-sarily result in higher market values (Eising et al., 2020) or better merchant profitability (Klie and Madlener, 2020). Therefore, the question arises whether an alternative allocation (i.e. a concentration) rather than diversification of the German wind park fleet is more economical. In this paper, we compare the future (2030) market values, subsidy needs and total system costs of a more concentrated versus a more diversified allocation of onshore wind turbines in Germany. The results show that a concentration of turbines, in areas where the gap between market values and levelized costs of electricity is smallest (i.e. in the North of Germany), is more beneficial in terms of subsidy need and system costs. The analysis further shows that these areas are also more beneficial in terms of market values, when using system-friendly turbine configurations selected based on the same approach. To incentivize such a selection of areas and turbine configurations based on minimal gaps between market values and levelized costs an alternative renewables support scheme is presented, which favors such minimal gaps in its auctioning process.

Taking on Technocracy: Nuclear Power in Germany, 1945 to the Present. Dolores L. Augustine. New York: Berghahn Books, 2018. xiv + 289 pp. Illustrations, graphs, notes, bibliography, and index. Cloth $120, e-book $110.16.

<i> Taking on Technocracy: Nuclear Power in Germany, 1945 to the Present. </i> Dolores L. Augustine. New York: Berghahn Books, 2018. xiv + 289 pp. Illustrations, graphs, notes, bibliography, and index. Cloth $120, e-book $110.16.

Significant multidecadal variability in German wind energy generation

Abstract. Wind energy has seen large deployment and substantial cost reductions over the last decades. Further ambitious upscaling is urgently needed to keep the goals of the Paris Agreement within reach. While the variability in wind power generation poses a challenge to grid integration, much progress in quantifying, understanding and managing it has been made over the last years. Despite this progress, relevant modes of variability in energy generation have been overlooked. Based on long-term reanalyses of the 20th century, we demonstrate that multidecadal wind variability has significant impact on wind energy generation in Germany. These modes of variability can not be detected in modern reanalyses that are typically used for energy applications because modern reanalyses are too short (around 40 years of data). We show that energy generation over a 20-year wind park lifetime varies by around ±5 % and the summer-to-winter ratio varies by around ±15 %. Moreover, ERA-Interim-based annual and winter generations are biased high as the period 1979–2010 overlaps with a multidecadal maximum of wind energy generation. The induced variations in wind park lifetime revenues are on the order of 10 % with direct implications for profitability. Our results suggest rethinking energy system design as an ongoing and dynamic process. Revenues and seasonalities change on a multidecadal timescale, and so does the optimum energy system layout.

Embeddedness of German wind turbine manufacturers in industrial relations institutions? Empirical insights from selected cases

Über die personal- und arbeitspolitischen Besonderheiten in den Unternehmen der Erneuerbaren Energiewirtschaft ist vergleichsweise wenig bekannt. Dabei bieten insbesondere diese neu entstehenden bzw. entstandenen Branchen eine hervorragende Möglichkeit, die Verankerung in arbeitspolitischen Institutionen im Allgemeinen und im deutschen Kontext kollektiver Arbeitsbeziehungen im Besonderen zu erkunden. Der vorliegende Beitrag zielt daher auf die Beantwortung der Frage, ob und auf welche Weise im Zuge einer sich herausbildenden Personalpolitik auch eine arbeitspolitische Verankerung erfolgt und inwieweit inner- und überbetriebliche Kontextbedingungen auf diese Entwicklung einwirken.

Do German renewable energy resources affect prices and mitigate market power in the French electricity market ?

ABSTRACTSeveral empirical studies show that renewable energy sources such as wind and solar power, typically supplied at low marginal cost, can cause electricity market prices to fall. Recent theoretical research and simulations also highlight the link between the integration of renewable energy and market performance in an oligopolistic energy market. This article looks at these dynamics in the context of cross-border effects between two highly interconnected electricity markets, France and Germany. Using a rich panel dataset for hourly data from November 2009 to July 2015, I estimate the impact of German wind and solar power production on both prices and market power in the French wholesale market. The findings highlight the importance of coordinating energy policies via joint renewable energy support schemes among interconnected European electricity markets.

Socio-technical constraints in German wind power planning: An example of the failed interdisciplinary challenge for academia

Germany has emerged as the global leader in wind project development, a large share of the country’s electricity produced by domestic wind turbines. Similar to other countries with a high penetration of wind power installations, there are numerous restrictions in Germany that could potentially stagnate the positive development towards the country’s renewable energy targets for 2050. These restrictions risk causing delays and cost overruns in the development of onshore wind projects, which can increase the levelized cost of energy and even halt the development of new wind farms. This study aims to inform German wind industry stakeholders about the current restrictions by producing a socio-technical wind atlas, which also suits as a resource map for new project investments. The atlas is a geographical information system developed for Germany, which is supplemented with interdisciplinary parameters and built on open source data. Moreover, the socio-technical wind atlas has been developed using seamless vector data. To determine the area available for wind power development, a raster calculation with a spatial resolution of 10 × 10 m was performed, making it the most precise source for new wind project development restrictions in Germany today. The methodology and data used aim to aid similar developments of decision support systems for wind power development in other countries, region or even globally.

Raw metal needs and supply risks for the development of wind energy in Germany until 2050

Facilitated by the environmental goals set by the government, wind turbines will be one of the main pillars of the future electricity production in Germany. In this paper, a comprehensive assessment of the future metallic raw material requirements for the development of the German wind energy sector was conducted, which is closely based on the current and future market conditions. Copper and dysprosium are identified as the most critical materials since they face the possibility of supply bottlenecks while being fundamental to the functionality of wind turbines. While the cumulative demand for copper may require 0.2% of the current known reserves, the demand for dysprosium may reach up to 0.6% of the reserve levels. Both metals clearly exceed the allocations for renewable energy technologies in Germany and would face strong competition from other sectors in securing raw materials. Although recycling is able to reduce the bottleneck risks, it does not completely mitigate them. More efforts are therefore required to improve material efficiency by means of alternative turbine designs, efficient production techniques, highly reliable components and material substitution.

Failure Modes, Effects and Criticality Analysis for Wind Turbines Considering Climatic Regions and Comparing Geared and Direct Drive Wind Turbines

The wind industry is looking for ways to accurately predict reliability and availability of newly installed wind turbines. Failure modes, effects and criticality analysis (FMECA) is a technique utilized to determine the critical subsystems of wind turbines. There are several studies in the literature which have applied FMECA to wind turbines, but no studies so far have used it considering different weather conditions or climatic regions. Furthermore, different wind turbine design types have been analyzed applying FMECA either distinctively or combined, but no study so far has compared the FMECA results for geared and direct-drive wind turbines. We propose to fill these gaps by using Koppen-Geiger climatic regions and two different turbine models of direct-drive and geared-drive concepts. A case study is applied on German wind farms utilizing the Wind Measurement &amp; Evaluation Programme (WMEP) database which contains wind turbine failure data collected between 1989 and 2008. This proposed methodology increases the accuracy of reliability and availability predictions and compares different wind turbine design types and eliminates underestimation of impacts of different weather conditions.