Risk Analysis of Wind Energy Investments in Turkey

ABSTRACT

Wind energy is a reliable source for fulfilling energy demand. However, the wind power usage remains limited due to the investmental risks. Governments’ support on renewable energy compensates these risks partially. Traditional investment evaluation techniques that do not consider the compensations and risks associated with the wind energy investments are one of the main reasons for the limited usage of wind power. In this study a real option and Monte Carlo simulation–based methodology, which considers both risks and compensations associated with these investments, is proposed to evaluate wind energy investments. The model is applied to a wind turbine investment in Turkey in order to show the applicability of the proposed model. The results indicate that the option value created through wind energy investments due to the governmental compensations is very high; therefore the traditional investment techniques are not appropriate for evaluating wind energy investments.     

The Potential Wind Power Resource in Australia: A New Perspective

Australia’s wind resource is considered to be very good, and the utilization of this renewable energy resource is increasing rapidly: wind power installed capacity increased by 35% from 2006 to 2011 and is predicted to account for over 12% of Australia’s electricity generation in 2030. Due to this growth in the utilization of the wind resource and the increasing importance of wind power in Australia’s energy mix, this study sets out to analyze and interpret the nature of Australia’s wind resources using robust metrics of the abundance, variability and intermittency of wind power density, and analyzes the variation of these characteristics with current and potential wind turbine hub heights. We also assess the extent to which wind intermittency, on hourly or greater timescales, can potentially be mitigated by the aggregation of geographically dispersed wind farms, and in so doing, lessen the severe impact on wind power economic viability of long lulls in wind and power generated. Our results suggest that over much of Australia, areas that have high wind intermittency coincide with large expanses in which the aggregation of turbine output does not mitigate variability. These areas are also geographically remote, some are disconnected from the east coast’s electricity grid and large population centers, which are factors that could decrease the potential economic viability of wind farms in these locations. However, on the eastern seaboard, even though the wind resource is weaker, it is less variable, much closer to large population centers, and there exists more potential to mitigate it’s intermittency through aggregation. This study forms a necessary precursor to the analysis of the impact of large-scale circulations and oscillations on the wind resource at the mesoscale.     

Should China subsidize cofiring to meet its 2020 bioenergy target? A spatio‐techno‐economic analysis

China has developed ambitious bioenergy installation targets as part of its broader goals to increase its renewable energy‐generating capacity and decarbonize its economy. A key target feedstock for bioenergy is the 800 million tonnes of agricultural residues that China produces each year. At present, the main financial incentive to support bioenergy generation from agricultural residues is a feed‐in‐tariff provided for bioenergy that is produced by units that take 80% or more of their feedstock energy from biomass. Although this policy has catalysed the construction of many bioenergy units, there are reports that these projects are experiencing serious financial and technical problems, leading to low operational efficiency and even closure. An alternative option for China's agricultural residues is cofiring with coal in existing power stations. However, this is currently unprofitable for power station operators, as cofiring is not eligible for financial assistance through the bioenergy feed‐in‐tariff. In the light of China's ambitious target to install 30GW of bioenergy generation capacity by 2020, this study investigates the extent to which extension of the bioenergy feed‐in‐tariff to include cofiring could contribute towards this goal. The results suggest that 39% of China's straw energy resources are located within 50 km of a power station. Assuming cofiring ratios of up to 10% coal energy replacement, an annual 89–117TWh of electricity could be generated by cofiring agricultural residues collected within 50 km radii of power stations. If China extends its bioenergy subsidies to include cofiring, an annual 62–92TWh can be produced at an internal rate of return of 8% or more. This equates to 42–62% of the bioenergy generation that China might expect if it met its 2020 target of installing 30GW of bioenergy capacity. Overall, this indicates a strong case for the Chinese government to extend its existing bioenergy feed‐in‐tariff to include cofiring at low energy replacement ratios.     

Scavenging Wind Energy by Triboelectric Nanogenerators

To meet future needs for clean and sustainable energy, tremendous progress has been achieved in development for scavenging wind energy. The most classical approach is to use the electromagnetic effect based wind turbine with a diameter of larger than 50 m and a weight of larger than 50 ton, and each of them could cost more than $0.5 M, which can only be installed in remote areas. Alternatively, triboelectric nanogenerators based on coupling of contact‐electrification and electrostatic induction effects have been utilized to scavenge wind energy, which takes the advantages of high voltage, low cost, and small size. Here, the development of a wind‐driven triboelectric nanogenerator by focusing on triboelectric materials optimization, structure improvement, and hybridization with other types of energy harvesting techniques is reviewed. Moreover, the major applications are summarized and the challenges that are needed to be addressed and development direction for scavenging wind energy in future are highlighted.     

Risk Management Model of a Micro-Grid Wind Farm

Micro-grid operation mode, which is the combination of a power grid and distributed generation, is the main way for saving investment, reducing energy consumption, and improving a power system's reliability and flexibility, but it has many risks in the process of implementation. In this article, the micro-grid generation structure of a wind farm was established, a processing flow chart of an intelligent management system was drawn, and a risk management model of a micro-grid wind farm was built from the angle of cost risk, including construction of cost risk and operation cost risk models. The construction cost risk model, grid-connected operation, and isolate-operation cost risk model of a micro-grid wind farm were set up by using a mathematical model that consisted of an objective function and constraint conditions. The accuracy of the model was verified through empirical analysis. This provides a reference and mirror for solving grid-connected wind energy problems and gives an important basis for wind energy risk policy-making, and for avoiding the risks in the process of planning, design, and operation management of a wind farm.     

Status quo and perspectives of biogas production for energy and material utilization

Biogas is in many respects a serious alternative to other fossil resources and complements other renewable energy sources from wind and sun. Biogas can be produced in many places decentrally. Its energy potential is high, and it is widely used in the EU and all over the world. With more than 16,000 ktoe of oil equivalent in the EU in 2016, it corresponds to approximately 8% of the total primary energy produced by renewable energies in the EU, produced with nearly 17,000 biogas plants. Nevertheless, the production costs of biogas and its products like energy, heat, and fuel are still too high. Kost et al. (2018) show a comparison of electricity generation costs of different renewable energies and their future potentials. While electricity from huge biogas plants offers generation costs from 10 to 15 ct/kWh, electricity from onshore wind and huge solar systems offers generation costs from 4 to 8 ct/kWh. Although substantial progress has been made with regard to substrate use, production techniques and market designs, many more innovations are needed throughout the biogas value chain for it to be competitive in energy markets without high subsidies. As several papers in the special issue on biogas show, there are numerous innovations and product designs with regard to energy and material uses that could maintain or even increase the importance of biogas production both within and outside of the EU. There are many potential benefits of biogas, as it offers high shares of produced renewable energies as well as large amounts of material products like digestates and in future maybe products of higher value such as proteins or lactic acids.     

Life Cycle Assessment of Offshore Wind Farm Siting: Effects of Locational Factors,Lake Depth,and Distance from Shore

According to previous studies, the life cycle energy intensity of an offshore wind farm (OWF) varies between 0.03 and 0.13 megawatt‐hours (MWh) of primary energy for each MWh of electricity generated. The variation in these life cycle energy intensity studies, after normalizing for capacity factor and life span, is significantly affected by OWF location because of geographical properties, namely, wind speed and water depth. To improve OWF siting, this study investigates how an OWF's distance from shore and geographical location impacts its environmental benefit. A process‐based life cycle assessment is conducted to compare 20 OWF siting scenarios in Michigan's Great Lakes for their cumulative fossil energy demand, global warming potential, and acidification potential. Each scenario (four lake locations at five offshore distances) has unique foundation, transmission, installation, and operational requirements based on site characteristics. The results demonstrate that the cumulative environmental burden from an OWF is most significantly affected by (1) water depth, (2) distance from shore, and (3) distance to power grid, in descending order of importance, if all other site‐relevant variables are held constant. The results also show that when OWFs are sited further offshore, the benefit of increased wind energy generation does not necessarily outweigh the increase in negative environmental impacts. This suggests that siting OWF nearer to shore may result in a better life cycle environmental performance. Finally, we demonstrate how much an OWF's environmental burdens can be reduced if the OWF system is either recycled, transported a shorter distance, or manufactured in a region with a high degree of renewable energy on the grid.     

Generating Electricity during Walking with a Lower Limb-Driven Energy Harvester: Targeting a Minimum User Effort

Background

Much research in the field of energy harvesting has sought to develop devices capable of generating electricity during daily activities with minimum user effort. No previous study has considered the metabolic cost of carrying the harvester when determining the energetic effects it has on the user. When considering device carrying costs, no energy harvester to date has demonstrated the ability to generate a substantial amount of electricity (> 5W) while maintaining a user effort at the same level or lower than conventional power generation methods (e.g. hand crank generator).

Methodology/Principal Findings

We developed a lower limb-driven energy harvester that is able to generate approximately 9W of electricity. To quantify the performance of the harvester, we introduced a new performance measure, total cost of harvesting (TCOH), which evaluates a harvester’s overall efficiency in generating electricity including the device carrying cost. The new harvester captured the motion from both lower limbs and operated in the generative braking mode to assist the knee flexor muscles in slowing the lower limbs. From a testing on 10 participants under different walking conditions, the harvester achieved an average TCOH of 6.1, which is comparable to the estimated TCOH for a conventional power generation method of 6.2. When generating 5.2W of electricity, the TCOH of the lower limb-driven energy harvester (4.0) is lower than that of conventional power generation methods.

Conclusions/Significance

These results demonstrated that the lower limb-driven energy harvester is an energetically effective option for generating electricity during daily activities.     

The Application of Cash-Flow-at-Risk to Risk Management in a Deregulated Electricity Market

The current level of deregulation in electricity markets is continuing to expand. Although each of these markets has individual operational and financial structures, one common characteristic is volatility. This volatility is significant and time-varying, and the persistence of this volatility makes the management of financial risk a priority among market participants.

This article considers two applications of an innovative spot price model to risk management in such a market. The first application is the empirical estimation of risk premia in the market considered here. The results support other approaches, which find the risk premia to be both significant and time-variant. In addition, this work considers the application of a Cash-Flow-at-Risk (CFaR) approach to measuring and comparing financial risk among various portfolio alternatives. These portfolios are considered from the perspective of the electricity producer, and the electricity purchaser. This approach is flexible and practical, allowing the comparison among portfolios and across seasons. The results of this analysis show that derivative instruments are significantly over-priced in this market, and that producers have the opportunity to earn significant profits, above those justified by the inherent risk in the market.     

Energy Sprawl or Energy Efficiency: Climate Policy Impacts on Natural Habitat for the United States of America

Concern over climate change has led the U.S. to consider a cap-and-trade system to regulate emissions. Here we illustrate the land-use impact to U.S. habitat types of new energy development resulting from different U.S. energy policies. We estimated the total new land area needed by 2030 to produce energy, under current law and under various cap-and-trade policies, and then partitioned the area impacted among habitat types with geospatial data on the feasibility of production. The land-use intensity of different energy production techniques varies over three orders of magnitude, from 1.9–2.8 km²/TW hr/yr for nuclear power to 788–1000 km²/TW hr/yr for biodiesel from soy. In all scenarios, temperate deciduous forests and temperate grasslands will be most impacted by future energy development, although the magnitude of impact by wind, biomass, and coal to different habitat types is policy-specific. Regardless of the existence or structure of a cap-and-trade bill, at least 206,000 km² will be impacted without substantial increases in energy efficiency, which saves at least 7.6 km² per TW hr of electricity conserved annually and 27.5 km² per TW hr of liquid fuels conserved annually. Climate policy that reduces carbon dioxide emissions may increase the areal impact of energy, although the magnitude of this potential side effect may be substantially mitigated by increases in energy efficiency. The possibility of widespread energy sprawl increases the need for energy conservation, appropriate siting, sustainable production practices, and compensatory mitigation offsets.     

Wind farm and solar park effects on plant–soil carbon cycling: uncertain impacts of changes in ground‐level microclimate

Global energy demand is increasing as greenhouse gas driven climate change progresses, making renewable energy sources critical to future sustainable power provision. Land‐based wind and solar electricity generation technologies are rapidly expanding, yet our understanding of their operational effects on biological carbon cycling in hosting ecosystems is limited. Wind turbines and photovoltaic panels can significantly change local ground‐level climate by a magnitude that could affect the fundamental plant–soil processes that govern carbon dynamics. We believe that understanding the possible effects of changes in ground‐level microclimates on these phenomena is crucial to reducing uncertainty of the true renewable energy carbon cost and to maximize beneficial effects. In this Opinions article, we examine the potential for the microclimatic effects of these land‐based renewable energy sources to alter plant–soil carbon cycling, hypothesize likely effects and identify critical knowledge gaps for future carbon research.     

Predicting Bald Eagle Collision at Wind Energy Facilities

Bald eagles (Haliaeetus leucocephalus) are currently protected in the United States under the Bald and Golden Eagle Protection Act of 1940 and Migratory Bird Treaty Act of 1918. Given these protections and the increasing development of wind energy throughout the United States, it is important for regulators and the wind industry to understand the risk of bald eagle collisions with wind turbines. Prior probability distributions for eagle exposure rates and collision rates have been developed for golden eagles (Aquila chrysaetos) by the United States Fish and Wildlife Service (USFWS). Given similar information has not been available for bald eagles, the current recommendation by the USFWS is to use the prior probability distributions developed using data collected on golden eagles to predict take for bald eagles. But some evidence suggests that bald and golden eagles may be at different risk for collision with wind turbines and the prior probability distributions developed for golden eagles may not be appropriate for bald eagles. We developed prior probability distributions using data collected at MidAmerican Energy Company's operating wind energy facilities in Iowa, USA, from December 2014 to March 2017 for bald eagle exposure rates and collision rates. The prior probability distribution for collision rate developed for bald eagles has a lower mean collision rate and less variability relative to that developed for golden eagles. We determined that the prior probability distributions specific to bald eagles from these operating facilities are a better starting point for predicting take for bald eagles at operating wind energy facilities in an agricultural landscape than those developed for golden eagles. © 2021 The Wildlife Society.     

A Large-Scale Mitigation Experiment to Reduce Bat Fatalities at Wind Energy Facilities

ABSTRACT Until large numbers of bat fatalities began to be reported at certain North American wind energy facilities, wildlife concerns regarding wind energy focused primarily on bird fatalities. Due in part to mitigation to reduce bird fatalities, bat fatalities now outnumber those of birds. To test one mitigation option aimed at reducing bat fatalities at wind energy facilities, we altered the operational parameters of 21 turbines at a site with high bat fatalities in southwestern Alberta, Canada, during the peak fatality period. By altering when turbine rotors begin turning in low winds, either by changing the wind-speed trigger at which the turbine rotors are allowed to begin turning or by altering blade angles to reduce rotor speed, blades were near motionless in low wind speeds, which resulted in a significant reduction in bat fatalities (by 60.0% or 57.5%, respectively). Although these are promising mitigation techniques, further experiments are needed to assess costs and benefits at other locations.     

Prioritizing Avian Species for Their Risk of Population-Level Consequences from Wind Energy Development

Recent growth in the wind energy industry has increased concerns about its impacts on wildlife populations. Direct impacts of wind energy include bird and bat collisions with turbines whereas indirect impacts include changes in wildlife habitat and behavior. Although many species may withstand these effects, species that are long-lived with low rates of reproduction, have specialized habitat preferences, or are attracted to turbines may be more prone to declines in population abundance. We developed a prioritization system to identify the avian species most likely to experience population declines from wind facilities based on their current conservation status and their expected risk from turbines. We developed 3 metrics of turbine risk that incorporate data on collision fatalities at wind facilities, population size, life history, species’ distributions relative to turbine locations, number of suitable habitat types, and species’ conservation status. We calculated at least 1 measure of turbine risk for 428 avian species that breed in the United States. We then simulated 100,000 random sets of cutoff criteria (i.e., the metric values used to assign species to different priority categories) for each turbine risk metric and for conservation status. For each set of criteria, we assigned each species a priority score and calculated the average priority score across all sets of criteria. Our prioritization system highlights both species that could potentially experience population decline caused by wind energy and species at low risk of population decline. For instance, several birds of prey, such as the long-eared owl, ferruginous hawk, Swainson’s hawk, and golden eagle, were at relatively high risk of population decline across a wide variety of cutoff values, whereas many passerines were at relatively low risk of decline. This prioritization system is a first step that will help researchers, conservationists, managers, and industry target future study and management activity.     

A Comprehensive Analysis of Small-Passerine Fatalities from Collision with Turbines at Wind Energy Facilities

Small passerines, sometimes referred to as perching birds or songbirds, are the most abundant bird group in the United States (US) and Canada, and the most common among bird fatalities caused by collision with turbines at wind energy facilities. We used data compiled from 116 studies conducted in the US and Canada to estimate the annual rate of small-bird fatalities. It was necessary for us to calculate estimates of small-bird fatality rates from reported all-bird rates for 30% of studies. The remaining 70% of studies provided data on small-bird fatalities. We then adjusted estimates to account for detection bias and loss of carcasses from scavenging. These studies represented about 15% of current operating capacity (megawatts [MW]) for all wind energy facilities in the US and Canada and provided information on 4,975 bird fatalities, of which we estimated 62.5% were small passerines comprising 156 species. For all wind energy facilities currently in operation, we estimated that about 134,000 to 230,000 small-passerine fatalities from collision with wind turbines occur annually, or 2.10 to 3.35 small birds/MW of installed capacity. When adjusted for species composition, this indicates that about 368,000 fatalities for all bird species are caused annually by collisions with wind turbines. Other human-related sources of bird deaths, (e.g., communication towers, buildings [including windows]), and domestic cats) have been estimated to kill millions to billions of birds each year. Compared to continent-wide population estimates, the cumulative mortality rate per year by species was highest for black-throated blue warbler and tree swallow; 0.043% of the entire population of each species was estimated to annually suffer mortality from collisions with turbines. For the eighteen species with the next highest values, this estimate ranged from 0.008% to 0.038%, much lower than rates attributed to collisions with communication towers (1.2% to 9.0% for top twenty species).     

Adapting Stand‐Alone Renewable Energy Technologies for the Circular Economy through Eco‐Design and Recycling

Renewable energy (RE) technologies are looked upon favorably to provide for future energy demands and reduce greenhouse gas (GHG) emissions. However, the installation of these technologies requires large quantities of finite material resources. We apply life cycle assessment to 100 years of electricity generation from three stand‐alone RE technologies—solar photovoltaics, run‐of‐river hydro, and wind—to evaluate environmental burden profiles against baseline electricity generation from fossil fuels. We then devised scenarios to incorporate circular economy (CE) improvements targeting hotspots in systems’ life cycle, specifically (1) improved recycling rates for raw materials and (ii) the application of eco‐design. Hydro presented the lowest environmental burdens per kilowatt‐hour of electricity generation compared with other RE technologies, owing to its higher efficiency and longer life spans for main components. Distinct results were observed in the environmental performance of each system based on the consideration of improved recycling rates and eco‐design. CE measures produced similar modest savings in already low GHG emissions burdens for each technology, while eco‐design specifically had the potential to provide significant savings in abiotic resource depletion. Further research to explore the full potential of CE measures for RE technologies will curtail the resource intensity of RE technologies required to mitigate climate change.     

Can Efficiency Improvements Reduce Resource Consumption?

This work explores the historical effectiveness of efficiency improvements in reducing humankind's consumption of energy resources. Ten activities are analyzed, including pig iron production, aluminum production, nitrogen fertilizer production, electricity generation from coal, electricity generation from oil, electricity generation from natural gas, freight rail travel, passenger air travel, motor vehicle travel, and residential refrigeration. The data and analyses presented here demonstrate the dynamic interplay between technological innovation, market forces, and government policy. They also show that, historically, over long time periods, incremental improvements in efficiency have not succeeded in outpacing increases in the quantity of goods and services provided. Thus, the end result over these time periods has been, not surprisingly, a sizeable increase in the consumption of energy resources across all ten activities. However, there do exist a few examples of shorter, decade‐long time periods in which improvements in efficiency were able to match or outpace increases in quantity. In these cases, efficiency mandates, price pressures, and industry upheaval led to periods of reduced resource consumption. These cases suggest that with appropriate incentives, including, for example, efficiency mandates and price mechanisms, future resource consumption, and its associated environmental impacts, could be stabilized and even reduced.     

Sun,wind, and the rebirth of extractive economies: renewable energy investment and metanarratives of crisis in Greece

In the midst of economic crisis, the Greek state has taken the unprecedented step of opening many of the nation's closed business sectors to international investors. Opportunities for multinational investment have been most prolific in the arena of renewable energy, where foreign prospecting in solar and wind energy is soaring. This article discusses two renewable energy initiatives: photovoltaic parks on agricultural land in Thessaly, central mainland Greece, and a planned wind farm development on the Aegean island of Chios. Among the people of Thessaly and Chios, the renewable energy initiatives are widely seen in terms of conquest and occupation akin to the Ottoman era and the Second World War. Harnessing natural resources is perceived to be a colonial programme of economic extraction associated with the global South as much as a sustainable energy initiative, heralding a return to a time of foreign occupation. This article examines the dialectical relationship emerging between narratives of renewable energy extraction and broader, long‐standing conceptions of Greek identity.     

The Water Withdrawal Footprint of Energy Supply to Cities

Water footprints traditionally estimate water lost as a result of evapotranspiration (or otherwise unavailable for downstream uses) associated with producing a certain good, and the same embodied in trade across regions is used to estimate regional and national water footprints. These footprints, however, do not address risk posed to city energy supplies characterized by insufficient streamflow to support energy production, such as cooling water intake (e.g., withdrawals) at thermoelectric power plants. Water withdrawal intensity factors for producing goods and services are being developed at the national scale, but lack sufficient spatial resolution to address these types of water‐energy challenges facing cities. To address this need, this article presents a water withdrawal footprint for energy supply (WWFES) to cities and places it in the context of other water footprints defined in the literature. Analysis of electricity use versus electricity generation in 43 U.S. cities highlights the need for developing WWFES to estimate risks to transboundary city energy supplies resulting from water constraints. The magnitude of the WWFES is computed for Denver, Colorado, and compared to the city's direct use of water to offer perspective. The baseline WWFES for Denver is found to be 66% as large as all direct water uses in the city combined (mean estimate). Minimum, mean, and maximum estimates are computed to demonstrate sensitivity of the WWFES to selection of water withdrawal intensity factors. Finally, scenario analysis explores the effect of energy technology and energy policy choices in shaping the future water footprint of cities.     

Development by design: mitigating wind development's impacts on wildlife in Kansas

Wind energy, if improperly sited, can impact wildlife through direct mortality and habitat loss and fragmentation, in contrast to its environmental benefits in the areas of greenhouse gas, air quality, and water quality. Fortunately, risks to wildlife from wind energy may be alleviated through proper siting and mitigation offsets. Here we identify areas in Kansas where wind development is incompatible with conservation, areas where wind development may proceed but with compensatory mitigation for impacts, and areas where development could proceed without the need for compensatory mitigation. We demonstrate that approximately 10.3 million ha in Kansas (48 percent of the state) has the potential to provide 478 GW of installed capacity while still meeting conservation goals. Of this total, approximately 2.7 million ha would require no compensatory mitigation and could produce up to 125 GW of installed capacity. This is 1,648 percent higher than the level of wind development needed in Kansas by 2030 if the United States is to get 20 percent of its electricity from wind. Projects that avoid and offset impacts consistent with this analysis could be awarded "Green Certification." Certification may help to expand and sustain the wind industry by facilitating the completion of individual projects sited to avoid sensitive areas and protecting the industry's reputation as an ecologically friendly source of electricity.