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Unless indicated otherwise, documents presented here are not the product of nor are they necessarily endorsed by National Wind Watch. These resource documents are shared here to assist anyone wishing to research the issue of industrial wind power and the impacts of its development. The information should be evaluated by each reader to come to their own conclusions about the many areas of debate. • The copyrights reside with the sources indicated. As part of its noncommercial effort to present the environmental, social, scientific, and economic issues of large-scale wind power development to a global audience seeking such information, National Wind Watch endeavors to observe “fair use” as provided for in section 107 of U.S. Copyright Law and similar “fair dealing” provisions of the copyright laws of other nations.

Date added:  November 5, 2022
Colorado, Property valuesPrint storyE-mail story

Impact Analysis of the Niyol Wind Farm on Surrounding Rural Residential and Agricultural Land Values in Logan County, Colorado

Author:  Forensic Appraisal GroupForensic Appraisal Group

Prepared for Concerned Citizens for a Safe Logan County, Sterling, Colorado, by Forensic Appraisal Group, Neenah, Wisconsin – June 11, 2020

This report was contracted by Concerned Citizens for a Safe Logan County for our opinion on how the 200.8MW Niyol Wind LLC will impact rural residential and agricultural farm values within the wind farm footprint and 1-mile outside of this zone of this proposed wind farm.

Niyol Wind is a wholly owned subsidiary of NextEra Energy. The wind farm is located in the Fleming area, Logan County, Colorado. The conditional use permit submitted by Niyol states that the wind farm will occupy 39,314 acres of area. The development will have 89 wind turbines, having a height (including the tower and blades at 12 o’clock position) of 495ft-505ft. The project will include graveled access roads over private land to the wind turbines, a maintenance area of approximately 4-acres, a substation of 10-acres graveled with a chain-link security fence and outside yard lighting, two meteorological towers being 275ft in height, underground and above ground electrical supply lines and a thirty-one mile 230kV high voltage transmission line that is to link up with an existing high voltage transmission line for transmission of the produced energy. The three-blade wind turbines will be one of two models: the GE 2.5MW turbine or the GE 2.8MW. The electrical collector lines are to be buried, the collector substation is above ground and connected to an overhead 230kV high voltage transmission line.

The study results are summarized as follows.

Literature Study

The media generally portrays the impact of wind turbines on residential properties as negative, bringing up fear factors and conflicting benefit, or no benefit issues. Overall, the qualitative factor is centered along the lines of health, noise, flicker, and viewshed. With regard to the question, “Do wind turbines affect property value?” the two Centerville Township (Michigan) officials summed it up with this statement: “It is totally counterintuitive to suggest anything else.”

Impact Studies

Wind industry and government supported studies found little to no evidence of an impact. However, independent studies found a significant impact using a variety of valuation methods from paired sales analysis to multi-regression analysis.

The Landsink (Ontario, CA) study found a loss range of −8.85% to −50%, with a loss average of −39% for residential homes within 664ft to 2,531ft of a wind farm.

The Appraisal Group One Wisconsin Study found a typical loss of 1-10 acre residential lots within 1⁄2-mile of wind turbines to be −19% to −40%.

The Clarkson University upstate New York study of both residential and agricultural properties found a loss ranging from −15.6% to −31% within 1-3 miles of a wind farm.

The Forensic Appraisal Coral Springs (WY) study of large residential lots (35 acres) which would be abutting a proposed wind farm suffered a value impact of −25% to −44%.

The McCann study (IL) of residential properties found an average impact of −25% within 2-miles of a wind farm.

The Forensic Appraisal Big Sky (IL) study found a loss range of −12% to −25% of residences within 0.31mi to 1.72mi of a wind turbine, with an average impact of −19% at an average distance of 0.65 miles to a wind turbine.

The Twin Grove II Wind Farm (McLean County, IL) study of a 198MW wind farm comprised of 120 turbines being 397ft in height over an 11,000 acres area. A paired sales analysis of residential property within the influence of the wind farm found the improved property is negatively impacted by the presence of wind turbines. The impact measured ranged from −46.6% to −7.7%, with the higher impact closest to the wind turbines and the impact diminishing as the distance is increased. The distances measured ranged 1,483ft to 5,481ft away from a residence.

The Twin Grove II Wind Farm also found an overall impact of −6.63% to −8.5% for vacant agricultural properties within the wind farm zone.

We conclude that the following impacts will be experienced by the Niyol wind farm on the client’s properties:

Download original document: “Impact Analysis of the Niyol Wind Farm on Surrounding Rural Residential and Agricultural Land Values in Logan County, Colorado

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Date added:  November 5, 2022
NoisePrint storyE-mail story

Ground motions induced by wind turbines

Author:  Nagel, Sven; et al.

Abstract – Wind flow transfers forces to the wind turbine’s rotor blades. These then set the rotor in motion. The hub and the gearbox, where present, transfer this rotational energy to the generator for conversion into electrical power. All the rotating components have significant mass and are located at the head of a slender, elastic load-bearing tower in which they induce dynamic effects. The resulting vibrations, generated at the upper end of the tower, are modified by the dynamic properties of the tower structure and pass through the foundations into the ground. Broadband seismometers record these ground vibrations not only directly adjacent to the wind turbine but also at greater distances of (up to) several kilometers from the turbine. We are aware that local residents and opponents of wind power consider that these vibration phenomena bear potential negative health effects. In the context of this paper, seismic vibrations were measured at the foundation of a 2 MW reference turbine. These seismic signals were compared to numerical simulations. Based on this, we explain the physical background. In the past, any ground vibrations measured have usually been attributed exclusively to the excitation frequencies from the rotor. However, the investigations presented here show that the structural properties of the tower structure significantly influence the type and intensity of the vibrations induced in the ground and dominate the ground motion amplitudes. Finally, we show that the targeted use of absorbers can significantly reduce the vibrations induced in the ground.

Ground motions induced by wind turbines

Sven Nagel, Thomas Ummenhofer, Peter Knödel, Karlsruher Institut für Technologie, Stahl- und Leichtbau, Karlsruhe, Germany
Toni Zieger, Joachim Ritter, Geophysikalisches Institut, Karlsruher Institut für Technologie, Karlsruhe, Germany
Birger Luhmann, Stuttgarter Lehrstuhl für Windenergie, Institut für Flugzeugbau, Universität Stuttgart, Stuttgart-Vaihingen, Germany

Civil Engineering Design. 2021;3:73–86. doi:10.1002/cend.202100015

Download original document: “Ground motions induced by wind turbines

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Date added:  November 2, 2022
Environment, GermanyPrint storyE-mail story

Emergence of Large-Scale Hydrodynamic Structures Due to Atmospheric Offshore Wind Farm Wakes

Author:  Christiansen, Nils; et al.


… Over time, the extraction of energy by offshore wind farms results in extensive areas of reduced wind speed and subsequently the decrease of the shear-driven forcing at the sea surface boundary. As this reduces the momentum transfer from the atmosphere into the ocean, horizontal velocities and turbulent mixing initially decrease several tens of kilometers around offshore wind farms. Thereby the induced perturbations imply significant changes for the residual currents in the respective areas. Furthermore, convergence and divergence of water masses lead to the formation of sea surface elevation dipoles, which over time merge into large coherent structures. As shown here, these large-scale anomalies in the sea surface elevation are one of the main drivers of wake-related processes in the ocean. In addition to the general reduction of turbulent mixing, the large- scale sea level alterations trigger lateral and vertical changes in the temperature and salinity distribution and affect the hydrodynamics in areas covered by offshore wind farms. However, the magnitude of these changes is rather small compared to the long-term variability of temperature and salinity and can hardly be distinguished from the interannual variability. A severe overall impact by the wake effects on the ocean’s thermodynamic properties is thus not expected but rather large-scale structural change in the stratification strength and unanticipated mesoscale spatial variability in the mean current field. Nevertheless, further investigations are necessary to assess possible feedback on the air-sea exchange and thus potential impact on the regional atmospheric conditions, since surface heating along with the reduction in turbulent mixing influences the upward heat and momentum fluxes from the ocean into the atmosphere.

In this study, the structural changes in stratification become noticeable in a couple of ways. Firstly, we observed large dipole-related changes in the potential energy anomaly, as the geostrophic and baroclinic changes alter the temperature and salinity distribution. Secondly, the reduction of mixing at offshore wind farms results in the enhancement of the stratification strength, in particular, during the decline of the summer stratification. While the structural changes in stratification are minor in shallow mixed waters, the pronounced alterations in stratified waters can translate to the mixed layer depth, which likely increases or decreases depending on the respective stratification changes. This, in turn, might be crucial for marine ecosystem processes (Sverdrup, 1953). During the stratified summer months, the mixed layer depth is acting as barrier for nutrients and phytoplankton and plays a major role for the ecosystem dynamics. Therefore, induced fluctuations of the mixed layer depth can entail the intrusion of nutrients from the pycnocline into the surface mixed layer or the spreading of the nutrient-poor surface layer, respectively. The alterations in the nutrient availability, in turn, might affect local primary production and the nutrient balance. Thus, further studies are required to elucidate the impact on marine ecosystems and organisms in the North Sea, with regard to current and future wind farm scenarios. …

Nils Christiansen, Ute Daewel, and Bughsin Djath, Institute of Coastal Systems, Helmholtz-Zentrum Hereon, Geesthacht, Germany
Corinna Schrum, Center for Earth System Research and Sustainability, Institute of Oceanography, Universität Hamburg, Germany

Download original document: “Emergence of Large-Scale Hydrodynamic Structures Due to Atmospheric Offshore Wind Farm Wakes

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Date added:  October 27, 2022
EconomicsPrint storyE-mail story

Full Cost of Electricity “FCOE” and Energy Returns “eROI”

Author:  Shernikau, Lars; Hayden Smith, William; and Falcon, Rosemary


Understanding electricity generation’s true cost is paramount to choosing and prioritizing our future energy systems. This paper introduces the full cost of electricity (FCOE) and discusses energy returns (eROI). The authors conclude with suggestions for energy policy considering the new challenges that come with global efforts to “decarbonize”.

In 2021, debate started to occur regarding energy security (or rather electricity security) which was driven by an increase in electricity demand, shortage of energy raw material supply, insufficient electricity generation from wind and solar, and geopolitical challenges, which in turn resulted in high prices and volatility in major economies. This was witnessed around the world, for instance in China, India, the US, and of course Europe. Reliable electricity supply is crucial for social and economic stability and growth which in turn leads to eradication of poverty.

The authors explain and quantify the gap between installed energy capacity and actual electricity generation when it comes to variable renewable energy. The main challenges for wind and solar are its intermittency and low energy density, and as a result practically every wind mill or solar panel requires either a backup or storage, which adds to system costs.

Widely used levelized cost of electricity, LCOE, is inadequate to compare intermittent forms of energy generation with dispatchable ones and when making decisions at a country or society level. We introduce and describe the methodology for determining the full cost of electricity (FCOE) or the full cost to society. FCOE explains why wind and solar are not cheaper than conventional fuels and in fact become more expensive the higher their penetration in the energy system. The IEA confirms, “the system value of variable renewables such as wind and solar decreases as their share in the power supply increases”. This is illustrated by the high cost of the “green” energy transition.

We conclude with suggestions for a revised energy policy. Energy policy and investors should not favor wind, solar, biomass, geothermal, hydro, nuclear, gas, or coal but should support all energy systems in a manner which avoids energy shortage and energy poverty. All energy always requires taking resources from our planet and processing them, thus negatively impacting the environment. It must be humanity’s goal to minimize these negative impacts in a meaningful way through investments – not divestments – by increasing, not decreasing, energy and material efficiencies.

Therefore, the authors suggest energy policy makers to refocus on the three objectives, energy security, energy affordability, and environmental protection. This translates into two pathways for the future of energy:

(1) invest in education and base research to pave the path towards a New Energy Revolution where energy systems can sustainably wean off fossil fuels.

(2) In parallel, energy policy must support investment in conventional energy systems to improve their efficiencies and reduce the environmental burden of generating the energy required for our lives.

Additional research is required to better understand eROI, true cost of energy, material input, and effects of current energy transition pathways on global energy security.

Lars Schernikau, energy economist, entrepreneur, and commodity trader in energy raw materials, Zurich, Switzerland, and Technical University of Berlin, Germany
William Hayden Smith, Professor of Earth and Planetary Sciences, McDonnell Center for Space Sciences, Washington University, St. Louis, Missouri, USA
Rosemary Falcon, retired DSI-NRF SARChI Professor, Engineering Faculty, University of the Witwatersrand, Johannesburg, South Africa

Journal of Management and Sustainability; Vol. 12, No. 1; 2022

Full Cost of Electricity “FCOE” and Energy Returns “eROI”

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