Expansion Of Wind Energy Research Articles

Export credit agencies delivering finance for the green transition in times of crisis

AbstractExport credit agencies (ECAs) have an important and effective toolbox for accelerating and shaping development through financing and dealing with risk. Being a public finance provider involved in global trade and connecting with both suppliers (exporters) and buyers (governments, public buyers, and private corporations), EKF has gained insight into the perspective of the buyer, supplier and, in project finance, sponsors, of what it takes to make a deal materialise across international borders. This is a valuable insight for work with green technologies. However, to truly deliver on the green transition we need all parts of government and society to adapt in order to increase demand and supply for green solutions at a global level. Governments must also commit to constant adaptation and improvement of policies if we are to succeed in the short time we are facing. EKF has demonstrated how export credit finance can support the global expansion of wind energy and that providing financial incentives makes a difference. I believe that ECAs are ready to take up this next challenge by managing even larger risks, providing long‐term funding, and working together on improving our climate impact, which is key to achieving sustainable green development.

Projections of energy yield- and complementarity-driven wind energy expansion scenarios in the European Union

The intensified expansion of intermittent onshore wind energy in the European Union raises questions about electricity supply to cover future electricity demand. Complementary wind resource use is considered an option to keep the number of supply–demand mismatches low. Here, the hypothesis is tested that adopting an EU-wide coordinated, complementarity-driven wind energy expansion leads to less residual loads than energy yield-driven wind energy expansion. This study quantifies the European Union-wide complementarity considering site-specific adding of new wind turbines and compared complementarity- to energy-yield-driven wind turbine siting. The goal is to evaluate wind energy expansion and assess the relevance of wind turbine siting coordination levels. Six high-resolution (500 m × 500 m) wind turbine siting scenarios for 2019–2100 were developed. Other variable renewables such as solar and offshore wind energy and the load curves were held constant to focus solely on the influence of the wind turbine siting scenario. The efficient and complementary wind resource use is quantified based on four objective criteria. They are the renewable share of annual electricity consumption, the share of hourly electricity supply droughts, the hourly renewable share of the load, and its coefficient of variation. Depending on the wind turbine siting scenario, the renewable share of annual electricity consumption ranges from 69.1 % to 78.5 % in 2050 the EU. The results indicate that the range of renewable load share values is more than 50 % less under European Union-wide complementarity-driven wind turbine siting than under energy-yield-driven wind turbine siting. However, 100 % renewable electricity supply is achieved 13 years later than under energy-yield-driven siting under complementarity-driven siting. Thus, a flexible European Union-wide siting strategy that considers future demand development and expansion of other variable renewables is proposed.

Balancing future renewable energy infrastructure siting and associated habitat loss for migrating whooping cranes

The expansion of human infrastructure has contributed to novel risks and disturbance regimes in most ecosystems, leading to considerable uncertainty about how species will respond to altered landscapes. A recent assessment revealed that whooping cranes (Grus americana), an endangered migratory waterbird species, avoid wind-energy infrastructure during migration. However, uncertainties regarding collective impacts of other types of human infrastructure, such as power lines, variable drought conditions, and continued construction of wind energy infrastructure may compromise ongoing recovery efforts for whooping cranes. Droughts are increasing in frequency and severity throughout the whooping crane migration corridor, and the impacts of drought on stopover habitat use are largely unknown. Moreover, decision-based analyses are increasingly advocated to guide recovery planning for endangered species, yet applications remain rare. Using GPS locations from 57 whooping cranes from 2010 through 2016 in the United States Great Plains, we assessed habitat selection and avoidance of potential disturbances during migration relative to drought conditions, and we used these results in an optimization analysis to select potential sites for new wind energy developments that minimize relative habitat loss for whooping cranes and maximize wind energy potential. Drought occurrence and severity varied spatially and temporally across the migration corridor during our study period. Whooping cranes rarely used areas <5 km from human settlements and wind energy infrastructure under both drought and non-drought conditions, and <2 km from power lines during non-drought conditions, with the lowest likelihood of use near wind energy infrastructure. Whooping cranes differed in their selection of wetland and cropland land cover types depending on drought or non-drought conditions. We identified scenarios for wind energy expansion across the migration corridor and in select states, which are robust to uncertain drought conditions, where future loss of highly selected stopover habitats could be minimized under a common strategy. Our approach was to estimate functional habitat loss while integrating current disturbances, potential future disturbances, and uncertainty in drought conditions. Therefore, dynamic models describing potential costs associated with risk-averse behaviors resulting from future developments can inform proactive conservation before population impacts occur.

Hidden repowering potential of non-repowerable onshore wind sites in Germany

Feed-in tariff funding will cease by 2025 for more than 70% of the currently installed onshore wind turbines in Germany. For many wind turbines, the feasibility of repowering from a regulatory point of view is unknown; that is, a complete replacement of the old wind turbines with new, modern, and more efficient models. In Germany, restrictive regulations regarding the required minimum distances of wind turbines from residential and other protected areas may impede repowering, thereby rendering a site non-repowerable. Many of these wind turbine sites are well-established in terms of their acceptance by the local population. Our analysis shows that the potential of non-repowerable but well-established locations with more efficient technology at the same height is almost twice that of the sites qualified for repowering via higher wind turbines. The latest legislation of the German federal government prescribes minimum distances of 1,000 m between a wind turbine and the nearest residential buildings. This will slow down the expansion of onshore wind energy in Germany and decrease its contribution to climate neutrality. This study quantifies the nationwide effects of restrictive legislative minimum distance regulations on repowering potential by means of a developed geographic information system that utilizes highly detailed settlement structures.

Market Needs, Opportunities and Barriers for the Floating Wind Industry

This paper reviews the status of floating wind energy expansion, market needs, opportunities, and barriers. Even more expensive than many other generation technologies currently, the floating wind will contribute to the decarbonization of Europe. This document assesses the market strategies available to develop floating wind farms in Europe. The study includes four main phases in addition to the overview of the current state-of-the-art: a technology review, market outlook, opportunities, and commercialization barriers. During its development, the offshore wind has moved from experimentation to a final design (Semisubmersible/barge, Tension Leg Platform, and Spar).

Comparing and validating intra-farm and farm-to-farm wakes across different mesoscale and high-resolution wake models

Abstract. Numerical wind resource modelling across scales from the mesoscale to the turbine scale is of increasing interest due to the expansion of offshore wind energy. Offshore wind farm wakes can last several tens of kilometres downstream and thus affect the wind resources of a large area. So far, scale-specific models have been developed but it remains unclear how well the different model types can represent intra-farm wakes, farm-to-farm wakes as well as the wake recovery behind a farm. Thus, in the present analysis the simulation of a set of wind farm models of different complexity, fidelity, scale and computational costs are compared among each other and with SCADA data. In particular, two mesoscale wind farm parameterizations implemented in the mesoscale Weather Research and Forecasting model (WRF), the Explicit Wake Parameterization (EWP) and the Wind Farm Parameterization (FIT), two different high-resolution RANS simulations using PyWakeEllipSys equipped with an actuator disk model, and three rapid engineering wake models from the PyWake suite are selected. The models are applied to the Nysted and Rødsand II wind farms, which are located in the Fehmarn Belt in the Baltic Sea. Based on the performed simulations, we can conclude that both WRF + FIT (BIAS = 0.52 m s−1) and WRF + EWP (BIAS = 0.73 m s−1) compare well with wind farm affected mast measurements. Compared with the RANS simulations, baseline intra-farm variability, i.e. the wind speed deficit in between turbines, can be captured reasonably well with WRF + FIT using a resolution of 2 km, a typical resolution of mesoscale models for wind energy applications, while WRF + EWP underestimates wind speed deficits. However, both parameterizations can be used to estimate median wind resource reduction caused by an upstream farm. All considered engineering wake models from the PyWake suite simulate peak intra-farm wakes comparable to the high fidelity RANS simulations. However, they considerably underestimate the farm wake effect of an upstream farm although with different magnitudes. Overall, the higher computational costs of PyWakeEllipSys and WRF compared with those of PyWake pay off in terms of accuracy for situations when farm-to-farm wakes are important.

Long-Term Freezing Temperatures Frequency Change Effect on Wind Energy Gain (Eurasia and North America, 1950–2019)

The persistent freezing conditions in cold regions are the cause of ice accretion on mechanical and instrumental elements of wind turbines. Consequently, remarkable Annual Energy Production (AEP) losses are prone to occur in those wind farms. Following global expansion of wind energy, these areas have had increased study interest in recent years. The goal of these studies is an improved characterisation of the site for the installation of turbines, which could prevent unexpected high AEP losses due to ice accretion on them. In this context, this paper provides an estimation of the freezing temperatures frequency (FTF) at 100 m over latitudes and evaluates the changes during the last 70 years. To that end, hourly surface temperature data (2 m above surface) from the ERA5 reanalysis is used in the [50∘ N, 75∘ N] latitudinal belt for the period 1950–2019. The obtained results show an average reduction of FTF hours of 72.5 h/decade for all the domain, reaching a maximum decrease of 621 h/decade on the southeast coast of Greenland and a 60% annual reduction at a specific location in Scandinavia. In terms of AEP a maximum gain of more than 26% would be projected, as categorised by the the International Energy Agency.

Key factors influencing onshore wind energy development: A case study from the German North Sea region

The aim of this paper is to identify facilitating and hindering factors for onshore wind energy development near natural conservation regions, in particular in Lower Saxony's Wattenmeer region. An applied research approach was deployed to connect individual aspects of wind energy technology and establish a cross-disciplinary perspective on the expansion of wind energy. To this end, relevant facilitating and hindering factors were identified and then validated by a group of academic experts. The main factors were grouped within the framework of Strengths, Weaknesses, Opportunities and Threats. In a subsequent step, a sample of experts in the wind power sector evaluated the relative importance of the key factors, using an Analytic Hierarchy Process. The results show that factors positively influencing wind energy expansion exceed the hindering factors. Wind electricity is likely to benefit from opportunities such as climate change and from industry-specific strengths, for instance the competitiveness of wind in the German electricity market. Barriers and uncertainties that influence the further development of the sector relate to strict ecological protection laws and limited spatial opportunities for new projects. Finally, basic policy strategies were formulated which aim at fostering strengths and opportunities of wind energy development and at reducing weaknesses and threats.

Feasibility of Replacing Nuclear and Fossil Fuel Energy with Offshore Wind Energy: A Case for Taiwan

Adequate recognition of the offshore wind energy potential may help coastal states frame proper energy policies for replacing nuclear and fossil fuel energy. In this study, we examined the application potential of the offshore wind energy generated by 31 offshore wind farms designated by the Taiwanese government for future exploitation. Our findings indicate that offshore wind energy (through its substantial power generation volume and capacity factor) can play the most pivotal role in future power generation for Taiwan. A total of 59.3 TWh of electricity produced from offshore wind energy and solar photovoltaics (PVs) each year could replace the power generated from nuclear energy by 2025. Coal-fired power generation could be replaced by offshore wind energy and other renewables by 2032. The full exploitation of offshore wind farms as detailed in this study (103.4 TWh/year), together with other renewables, could reduce the share of liquefied natural gas-fired power generation to 5.6% of the total Taiwanese power supply by 2040. Realizing the ultimate target of 100% carbon-neutral power generation would rely mainly on a further decrease in electricity consumption per unit of gross domestic product and the expansion of offshore wind energy and geothermal energy.

Piloted Simulation of the Rotorcraft Wind Turbine Wake Interaction during Hover and Transit Flights

Helicopters are used for offshore wind farms for maintenance and support flights. The number of helicopter operations is increasing with the expansion of offshore wind energy, which stresses the point that the current German regulations have not yet been validated through scientific analysis. A collaborative research project between DLR, the Technical University of Munich, the University of Stuttgart and the University of Tübingen has been conducted to examine the sizes of the flight corridors on offshore wind farms and the lateral safety clearance for helicopter hoist operations at offshore wind turbines. This paper details the results of piloted helicopter simulations in a realistic offshore wind farm scenario. The far-wake of rotating wind turbines and the near-wake of non-rotating wind turbines have been simulated with high-fidelity computational fluid dynamics under realistic turbulent inflow conditions. The resulting flow fields have been processed by superposition during piloted simulations in the research flight simulator AVES to examine the flight corridors in transit flights and the lateral safety clearance in hovering flights. The results suggest a sufficient size for the flight corridor and sufficient lateral safety clearance at the offshore wind turbines in the considered scenarios.

Joint analysis of resident complaints, meteorological, acoustic, and ground motion data to establish a robust annoyance evaluation of wind turbine emissions

In order to advance the expansion of onshore wind energy, wind turbines (WTs) must be erected in often complex terrain. The orography and the associated meteorological conditions, as well as the complex propagation of sound and ground motion waves can lead to increased annoyance of residents.Here a joint investigation of residential noise reports, meteorological, acoustic and ground motion data together with operational parameters of a wind farm in southern Germany is presented, with the objective to assess the annoyance of residents affected by WT emissions. Once strongly annoyed residents had been identified, simultaneous measurements were conducted over a 2-month period while residents used a noise reporting app to document their annoyance. A combination of the data shows that WT-related signals can be detected by acoustic and ground motion measurements in the vicinity of the WTs and, to a lesser extent, at the residential sites. In addition, background noise can be identified well. The app data indicates higher complaint rates in the early morning, evening and night hours. Changes in rotation rate seem to be the cause of annoyance as well as high rotation rates. These findings can be used to adjust WT operation in order to decrease immissions.

Predicted wind and solar energy expansion has minimal overlap with multiple conservation priorities across global regions

Protected areas and renewable energy generation are critical tools to combat biodiversity loss and climate change, respectively. Over the coming decades, expansion of the protected area network to meet conservation objectives will be occurring alongside rapid deployment of renewable energy infrastructure to meet climate targets, driving potential conflict for a finite land resource. Renewable energy infrastructure can have negative effects on wildlife, and co-occurrence may mean emissions targets are met at the expense of conservation objectives. Here, we assess current and projected overlaps of wind and solar photovoltaic installations and important conservation areas across nine global regions using spatially explicit wind and solar data and methods for predicting future renewable expansion. We show similar levels of co-occurrence as previous studies but demonstrate that once area is accounted for, previous concerns about overlaps in the Northern Hemisphere may be largely unfounded, although they are high in some biodiverse countries (e.g., Brazil). Future projections of overlap between the two land uses presented here are generally dependent on priority threshold and region and suggest the risk of future conflict can be low. We use the best available data on protected area degradation to corroborate this level of risk. Together, our findings indicate that while conflicts between renewables and protected areas inevitably do occur, renewables represent an important option for decarbonization of the energy sector that would not significantly affect area-based conservation targets if deployed with appropriate policy and regulatory controls.

Balancing profitability of energy production, societal impacts and biodiversity in offshore wind farm design

The global demand for renewable energy is on the rise. Expansion of onshore wind energy is in many parts of the world limited by societal acceptance, and also ecological impacts are a concern. Here, pragmatic methods are developed for the integration of high-dimensional spatial data in offshore wind energy planning. Over 150 spatial data layers are created, which either oppose or support offshore wind energy development, and represent ecological, societal, and economic factors. The method is tested in Finland, where interest in developing offshore wind energy is growing.Analyses were done using a spatial prioritization approach, originally developed for the prioritization of high-dimensional ecological data, and rarely used in planning offshore wind energy. When all criteria are integrated, it is possible to find a balanced solution where offshore wind farms cause little disturbance to biodiversity and society, while at the same time yielding high profitability for wind energy production. Earlier proposed areas for offshore wind farms were also evaluated. They were generally well suited for wind power, with the exception of a couple of areas with comparatively high environmental impacts.As an outcome, new areas well suited for large scale wind power deployment were recognized, where construction costs would be moderate and disturbance to biodiversity, marine industries and people limited. A novel tradeoff visualization method was also developed for the conflicts and synergies of offshore energy deployment, which could ease the dialogue between different stakeholders in a spatial planning context.Overall, this study provides a generic and transparent approach for well-informed analysis of offshore wind energy development potential when conflict resolution between biodiversity, societal factors and economic profits is needed. The proposed approach is replicable elsewhere in the world. It is also structurally suitable for the planning of impact avoidance and conflict resolution in the context of other forms of construction or resource extraction.

Strategies for climate neutrality. Lessons from a meta-analysis of German energy scenarios

The ambition to reach climate-neutral energy systems requires profound energy transitions. Various scenario studies exist which present different options to reach that goal. In this paper, key strategies for the transition to climate neutrality in Germany are identified through a meta-analysis of published studies, including scenarios which achieve at least a 95 % greenhouse gas emissions reduction by 2050 compared to 1990. Reduction in energy demand, an expansion of domestic wind and solar energy, increased use of biomass as well as the importation of synthetic energy carriers are key strategies in the scenarios, with nuclear energy playing no role, and carbon capture and storage playing a very limited role. Demand-side solutions that reduce the energy demand have a very high potential to diminish the significant challenges of other strategies, which are all facing certain limitations regarding their potential. The level and type of demand reductions differ significantly within the scenarios, especially regarding the options of reducing energy service demand.

Greenhouse Gas Savings Potential under Repowering of Onshore Wind Turbines and Climate Change: A Case Study from Germany

Wind energy is crucial in German energy and climate strategies as it substitutes carbon-intensive fossil fuels and achieves substantial greenhouse gas (GHG) reductions. However, wind energy deployment currently faces several problems: low expansion rates, wind turbines at the end of their service life, or the end of remuneration. Repowering is a vital strategy to overcome these problems. This study investigates future annual GHG payback times and emission savings of repowered wind turbines. In total, 96 repowering scenarios covering a broad range of climatological, technical, economic, and political factors affecting wind energy output in 2025–2049 were studied. The results indicate that due to more giant wind turbines and geographical restrictions, the amount of repowerable sites is reduced significantly. Consequently, in most scenarios, emission savings will dramatically diminish compared to current savings. Even in the best-case scenario, the highest emission savings’ growth is at 11%. The most meaningful drivers of GHG payback time and emission savings are wind turbine type, geographical restrictions, and GHG emissions. In contrast, climate change impact on the wind resource is only marginal. Although repowering alone is insufficient for achieving climate targets, it is a substantial part of the wind energy strategy. It could be improved by the synergies of different measures presented in this study. The results emphasize that a massive expansion of wind energy is required to establish it as a cornerstone of the future energy mix.

Climate Change Mitigation Potential of Wind Energy

Global wind resources greatly exceed current electricity demand and the levelized cost of energy from wind turbines has shown precipitous declines. Accordingly, the installed capacity of wind turbines grew at an annualized rate of about 14% during the last two decades and wind turbines now provide ~6–7% of the global electricity supply. This renewable electricity generation source is thus already playing a role in reducing greenhouse gas emissions from the energy sector. Here we document trends within the industry, examine projections of future installed capacity increases and compute the associated climate change mitigation potential at the global and regional levels. Key countries (the USA, UK and China) and regions (e.g., EU27) have developed ambitious plans to expand wind energy penetration as core aspects of their net-zero emissions strategies. The projected climate change mitigation from wind energy by 2100 ranges from 0.3–0.8 °C depending on the precise socio-economic pathway and wind energy expansion scenario followed. The rapid expansion of annual increments to wind energy installed capacity by approximately two times current rates can greatly delay the passing of the 2 °C warming threshold relative to pre-industrial levels. To achieve the required expansion of this cost-effective, low-carbon energy source, there is a need for electrification of the energy system and for expansion of manufacturing and installation capacity.

Addressing the Effect of Social Acceptance on the Distribution of Wind Energy Plants and the Transmission Grid in Germany

Social acceptance is increasingly becoming a limiting factor in implementing the energy transition in Germany. From today’s perspective, the expansion of wind energy and future transmission grids is only somewhat a technical or economic challenge rather than a social one. Since political decisions on the energy system transformation are often derived from findings of energy system modeling, it seems necessary to increasingly integrate the effects of socio-ecological aspects, such as acceptance issues in energy models. In this paper, an approach is introduced to address effects of social acceptance in energy system models by comparing the influence of different distribution scenarios of wind energy in Germany on the expansion need for future transmission lines. The results show that a socio-ecologic distribution of onshore wind installations according to a balanced burden of the German society does not reduce the grid expansion need significantly compared to an economic siting. An actual reduction of planned transmission grids could just be achieved by a more decentral scenario, including decentral market design. The sensitivity of regionalization is an opportunity to consider local acceptance issues within energy system models and should move more into focus inside the procedure of the current grid development process in Germany.

Distance to power grids and consideration criteria reduce global wind energy potential the most

To reduce the negative implications associated with the use of conventional energies on the environment and human health, intensified renewable energy expansion is inevitable. Wind energy is one of the most promising renewable energies since the theoretical technical wind energy potential is far enough to cover the global electricity consumption. However, various geographical barriers reduce the wind potential to contribute to a more sustainable power supply. The main goal of this study was to quantify the percentage reduction of the theoretical technical wind energy potential due to geographical barriers. The geographical barriers were derived from seven land use models and an elevation model and classified into the restriction categories: (1) inaccessible areas (natural), (2) inaccessible areas (artificial), (3) protected areas, (4) missing infrastructure, and (5) consideration criteria. The theoretical technical wind energy potential was estimated by wind speed distributions from the Global Wind Speed Model and assuming a dense global onshore network of wind turbines within 500 m distances. The results reveal that the most significant theoretical technical wind energy potential loss results from missing infrastructure and soft consideration criteria. The global percentage energy reduction is 96.1 %. In most developing countries, lacking infrastructure was identified as the restriction category resulting in the most notable theoretical technical wind energy potential reduction. This result emphasizes the need to improve the accessibility to wind resources in developing countries by improving the electricity grid. In industrialized countries, consideration criteria (e.g., forests, agricultural areas, proximity to urban areas) cause the greatest theoretical technical wind energy potential reduction. Thus, the extent to which the theoretical technical wind energy potential is exploitable greatly depends on regulations, public acceptance, and agreements on competitive land use. By identifying the most relevant geographical barriers, the results of this study contribute to the development of country-specific frameworks for wind energy expansion.

Assessing the vulnerability of breeding bird populations to onshore wind-energy developments in Finland

Wind-energy expansion raises concerns over its potential impacts on bird populations. Birds may be affected directly via collision with turbines or indirectly via habitat loss or displacement due to disturbance. Species with long generation times, low reproductive output or high habitat specialisation are more likely to be impacted. Using national-scale breeding bird distributions, we applied a quantitative prioritisation method to assess the vulnerability of species to onshore wind-energy developments in Finland. We assessed 214 species that regularly breed in the country. Each species was assigned a priority score based on a combination of life-history traits, habitat specialisation, exposure to wind energy and conservation status. We found that the priority scores varied markedly between species, allowing a distinction between a minority of high-ranked species and a majority of low-ranked species. High-ranked species included terns (e.g., Sternula albifrons), raptors (e.g., Aquila chrysaetos), gulls (e.g., Larus fuscus), some forestdwelling passerines (e.g., Poecile montanus) and ducks (e.g., Aythya ferina). Lowranked species included woodpeckers (e.g., Picus canus) and many passerines. Our results indicate that the priority species are not limited to the more highly regarded large raptors, and that wind-energy impact assessments need to pay special attention to highranked species inhabiting coastal areas.

Modeling Wind Speed with a Long-Term Horizon and High-Time Interval with a Hybrid Fourier-Neural Network Model

The limited availability of local climatological stations and the limitations to predict the wind speed (WS) accurately are significant barriers to the expansion of wind energy (WE) projects worldwide. A methodology to forecast accurately the WS at the local scale can be used to overcome these barriers. This study proposes a methodology to forecast the WS with high-resolution and long-term horizons, which combines a Fourier model and a nonlinear autoregressive network (NAR). Given the nonlinearities of the WS variations, a NAR model is used to forecast the WS based on the variability identified with the Fourier analysis. The NAR modelled successfully 1.7 years of wind-speed with 3 hours of the time interval, what may be considered the longest forecasting horizon with high resolution at the moment.