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Session: Non-fatality and habitat impacts on birds from wind energy development

Description: This session at the Wind Energy and Birds/Bats workshop was consisted of one paper presentation followed by a discussion/question and answer period. The session focused on discussion of non-collision impacts of wind energy projects on birds, primarily impacts to habitat. The presentation included information about the impacts of habitat fragmentation, disturbance, and site avoidance from wind turbines, as well as from roads, transmission facilities, and other related construction at wind project sites. Whether birds habituate to the presence of turbines and the influence of regional factors were also addressed. The paper given by Dale Strickland was titled ''Overview of Non-Collision Related Impacts from Wind Projects''.
Date: September 1, 2004
Creator: Strickland, Dale
Partner: UNT Libraries Government Documents Department

Long-Term Wind Power Variability

Description: The National Renewable Energy Laboratory started collecting wind power data from large commercial wind power plants (WPPs) in southwest Minnesota with dedicated dataloggers and communication links in the spring of 2000. Over the years, additional WPPs in other areas were added to and removed from the data collection effort. The longest data stream of actual wind plant output is more than 10 years. The resulting data have been used to analyze wind power fluctuations, frequency distribution of changes, the effects of spatial diversity, and wind power ancillary services. This report uses the multi-year wind power data to examine long-term wind power variability.
Date: January 1, 2012
Creator: Wan, Y. H.
Partner: UNT Libraries Government Documents Department

Wind Power Plant Monitoring Project Annual Report

Description: The intermittent nature of the wind resource, together with short-term power fluctuations, are the two principal issues facing a utility with wind power plants in its power grid. To mitigate these issues, utilities, wind power plant developers, and operators need to understand the nature of wind power fluctuations and how they affect the electrical power system, as well as to analyze ancillary service requirements with real wind power plant output data. To provide the necessary data, NREL conducted a study to collect at least 2 years of long-term, high-frequency (1-hertz [Hz]) data from several medium- to large-scale wind power plants with different wind resources, terrain features, and turbine types. Researchers then analyzed the data for power fluctuations, frequency distribution of wind power (by deriving a probability distribution function of wind power plant output variations), spatial and temporal diversity of wind power, and wind power capacity credit issues. Results of these analyses can provide data on the potential effects of wind power plants on power system regulation.
Date: July 11, 2001
Creator: Wan, Y.
Partner: UNT Libraries Government Documents Department

Sliding Window Technique for Calculating System LOLP Contributions of Wind Power Plants

Description: Conventional electric power generation models do not typically recognize the probabilistic nature of the power variations from wind plants. Most models allow for an accurate hourly representation of wind power output, but do not incorporate any probabilistic assessment of whether the given level of wind power will vary from its expected value. The technique presented in this paper uses this variation to calculate an effective forced-outage rate for wind power plants (EFORW). Depending on the type of wind regime undergoing evaluation, the length and diurnal characteristics of a sliding time window can be adjusted so that the EFORW is based on an appropriate time scale. The algorithm allows us to calculate the loss-of-load probability (LOLP) on an hourly basis, fully incorporating the variability of the wind resource into the calculation. This makes it possible to obtain a more accurate assessment of reliability of systems that include wind generation when system reliability is a concern .
Date: September 18, 2001
Creator: Milligan, M. R.
Partner: UNT Libraries Government Documents Department

Session: What can we learn from developed wind resource areas

Description: This session at the Wind Energy and Birds/Bats workshop was composed of two parts intended to examine what existing science tells us about wind turbine impacts at existing wind project sites. Part one dealt with the Altamont Wind Resource area, one of the older wind projects in the US, with a paper presented by Carl Thelander titled ''Bird Fatalities in the Altamont Pass Wind Resource Area: A Case Study, Part 1''. Questions addressed by the presenter included: how is avian habitat affected at Altamont and do birds avoid turbine sites; are birds being attracted to turbine strings; what factors contribute to direct impacts on birds by wind turbines at Altamont; how do use, behavior, avoidance and other factors affect risk to avian species, and particularly impacts those species listed as threatened, endangered, or of conservation concern, and other state listed species. The second part dealt with direct impacts to birds at new generation wind plants outside of California, examining such is sues as mortality, avoidance, direct habitat impacts from terrestrial wind projects, species and numbers killed per turbine rates/MW generated, impacts to listed threatened and endangered species, to USFWS Birds of Conservation Concern, and to state listed species. This session focused on newer wind project sites with a paper titled ''Bird Fatality and Risk at New Generation Wind Projects'' by Wally Erickson. Each paper was followed by a discussion/question and answer period.
Date: September 1, 2004
Creator: Thelander, Carl & Erickson, Wally
Partner: UNT Libraries Government Documents Department

Using wind plant data to increase reliability.

Description: Operators interested in improving reliability should begin with a focus on the performance of the wind plant as a whole. To then understand the factors which drive individual turbine performance, which together comprise the plant performance, it is necessary to track a number of key indicators. Analysis of these key indicators can reveal the type, frequency, and cause of failures and will also identify their contributions to overall plant performance. The ideal approach to using data to drive good decisions includes first determining which critical decisions can be based on data. When those required decisions are understood, then the analysis required to inform those decisions can be identified, and finally the data to be collected in support of those analyses can be determined. Once equipped with high-quality data and analysis capabilities, the key steps to data-based decision making for reliability improvements are to isolate possible improvements, select the improvements with largest return on investment (ROI), implement the selected improvements, and finally to track their impact.
Date: January 1, 2011
Creator: Peters, Valerie A. (Sandia National Laboratories, Livermore, CA); Ogilvie, Alistair B. & McKenney, Bridget L.
Partner: UNT Libraries Government Documents Department

The EPRI/DOE Utility Wind Turbine Performance Verification Program

Description: In 1992, the Electric Power Research Institute (EPRI) and the US Department of Energy (DOE) initiated the Utility Wind Turbine Performance Verification Program (TVP). This paper provides an overview of the TVP, its purpose and goals, and the participating utility projects. Improved technology has significantly reduced the cost of energy from wind turbines since the early 1980s. In 1992, turbines were producing electricity for about $0.07--$0.09/kilowatt-hour (kWh) (at 7 m/s [16 mph sites]), compared with more than $0.30/kWh in 1980. Further technology improvements were expected to lower the cost of energy from wind turbines to $0.05/kWh. More than 17,000 wind turbines, totaling more than 1,500 MW capacity, were installed in the US, primarily in California and Hawaii. The better wind plants had availabilities above 95%, capacity factors exceeding 30%, and operation and maintenance costs of $0.01/kWh. However, despite improving technology, EPRI and DOE recognized that utility use of wind turbines was still largely limited to turbines installed in California and Hawaii during the 1980s. Wind resource assessments showed that other regions of the US, particularly the Midwest, had abundant wind resources. EPRI and DOE sought to provide a bridge from utility-grade turbine development programs under way to commercial purchases of the wind turbines. The TVP was developed to allow utilities to build and operate enough candidate turbines to gain statistically significant operating and maintenance data.
Date: January 1997
Creator: Calvert, S.; Goldman, P.; DeMeo, E.; McGowin, C.; Smith, B. & Tromly, K.
Partner: UNT Libraries Government Documents Department

Financing investments in renewable energy: The role of policy design and restructuring

Description: The costs of electric power projects utilizing renewable energy technologies are highly sensitive to financing terms. Consequently, as the electricity industry is restructured and new renewables policies are created, it is important for policymakers to consider the impacts of renewables policy design on project financing. This report describes the power plant financing process and provides insights to policymakers on the important nexus between renewables policy design and finance. A cash-flow model is used to estimate the impact of various financing variables on renewable energy costs. Past and current renewable energy policies are then evaluated to demonstrate the influence of policy design on the financing process and on financing costs. The possible impacts of electricity restructuring on power plant financing are discussed and key design issues are identified for three specific renewable energy programs being considered in the restructuring process: (1) surcharge-funded policies; (2) renewables portfolio standards; and (3) green marketing programs. Finally, several policies that are intended to directly reduce financing costs and barriers are analyzed. The authors find that one of the key reasons that renewables policies are not more effective is that project development and financing processes are frequently ignored or misunderstood when designing and implementing renewable energy incentives. A policy that is carefully designed can reduce renewable energy costs dramatically by providing revenue certainty that will, in turn, reduce financing risk premiums.
Date: March 1, 1997
Creator: Wiser, R. & Pickle, S.
Partner: UNT Libraries Government Documents Department

Environmental assessment, expanded Ponnequin wind energy project, Weld County, Colorado

Description: The US Department of Energy (DOE) has considered a proposal from the State of Colorado, Office of Energy Conservation (OEC), for funding construction of the Expanded Ponnequin Wind Project in Weld County, Colorado. OEC plans to enter into a contracting arrangement with Public Service Company of Colorado (PSCo) for the completion of these activities. PSCo, along with its subcontractors and business partners, are jointly developing the Expanded Ponnequin Wind Project. The purpose of this Final Environmental Assessment (EA) is to provide DOE and the public with information on potential environmental impacts associated with the Expanded Ponnequin Wind Energy Project. This EA, and public comments received on it, were used in DOE`s deliberations on whether to release funding for the expanded project under the Commercialization Ventures Program.
Date: February 1, 1999
Partner: UNT Libraries Government Documents Department

Estimating the economic value of wind forecasting to utilities

Description: Utilities are sometimes reluctant to assign capacity value to wind plants because they are an intermittent resource. One of the potential difficulties is that the output of a wind plant may not be known in advance, thereby making it difficult for the utility to consider wind output as firm. In this paper, we examine the economics of an accurate wind forecast, and provide a range of estimates calculated by a production cost model and real utility data. We discuss how an accurate forecast will affect resource scheduling and the mechanism by which resource scheduling can benefit from an accurate wind forecast.
Date: May 1, 1995
Creator: Milligan, M.R.; Miller, A.H. & Chapman, F.
Partner: UNT Libraries Government Documents Department

Alternative windpower ownership structures: Financing terms and project costs

Description: Most utility-scale renewable energy projects in the United States are developed and financed by private renewable energy companies. Electric output is then sold to investor-owned and public utilities under long-term contracts. Limited partnerships, sale/leaseback arrangements, and project-financing have historically been the dominant forms of finance in the windpower industry, with project-finance taking the lead more recently. Although private ownership using project-finance is still the most popular form of windpower development, alternative approaches to ownership and financing are becoming more prevalent. U.S. public and investor-owned electric utilities (IOUs) have begun to participate directly in windpower projects by owning and financing their own facilities rather than purchasing windpower from independent non-utility generators (NUGs) through power purchase agreements (PPAs). In these utility-ownership arrangements, the wind turbine equipment vendor/developer typically designs and constructs a project under a turnkey contract for the eventual project owner (the utility). The utility will also frequently sign an operations and maintenance (O&M) contract with the project developer/equipment vendor. There appear to be a number of reasons for utility involvement in recent and planned U.S. wind projects. One important claim is that utility ownership and self-finance provides substantial cost savings compared to contracting with private NUGs to supply wind-generated power. In this report, we examine that assertion.
Date: May 1, 1996
Creator: Wiser, R. & Kahn, E.
Partner: UNT Libraries Government Documents Department

Synthesis and Comparison of Baseline Avian and Bat Use, Raptor Nesting and Mortality Information from Proposed and Existing Wind Developments: Final Report.

Description: Primarily due to concerns generated from observed raptor mortality at the Altamont Pass (CA) wind plant, one of the first commercial electricity generating wind plants in the U.S., new proposed wind projects both within and outside of California have received a great deal of scrutiny and environmental review. A large amount of baseline and operational monitoring data have been collected at proposed and existing U.S. wind plants. The primary use of the avian baseline data collected at wind developments has been to estimate the overall project impacts (e.g., very low, low, moderate, and high relative mortality) on birds, especially raptors and sensitive species (e.g., state and federally listed species). In a few cases, these data have also been used for guiding placement of turbines within a project boundary. This new information has strengthened our ability to accurately predict and mitigate impacts from new projects. This report should assist various stakeholders in the interpretation and use of this large information source in evaluating new projects. This report also suggests that the level of baseline data (e.g., avian use data) required to adequately assess expected impacts of some projects may be reduced. This report provides an evaluation of the ability to predict direct impacts on avian resources (primarily raptors and waterfowl/waterbirds) using less than an entire year of baseline avian use data (one season, two seasons, etc.). This evaluation is important because pre-construction wildlife surveys can be one of the most time-consuming aspects of permitting wind power projects. For baseline data, this study focuses primarily on standardized avian use data usually collected using point count survey methodology and raptor nest survey data. In addition to avian use and raptor nest survey data, other baseline data is usually collected at a proposed project to further quantify potential impacts. These surveys often include vegetation ...
Date: December 1, 2002
Creator: Erickson, Wallace P.
Partner: UNT Libraries Government Documents Department

Wind energy: legal issues and institutional barriers

Description: Before the potential of wind energy can be realized, large-scale commercialization will have to occur. Standing in the way of commercial development are various institutional and legal barriers. These include (1) possible conflicts with existing zoning and other land-use planning schemes, (2) the question of guaranteeing access to the wind, (3) possible tort and environmental law issues raised by WECS operation, and (4) the critical problem of creating financial incentives. The implications of each of these issues and solutions where practicable are presented.
Date: June 1, 1979
Creator: Coit, L.
Partner: UNT Libraries Government Documents Department

Evaluating the risk-reduction benefits of wind energy

Description: The question of uncertainty and risk in electric utility resource planning has received considerable attention in recent years. During the 1980s, many utilities suffered financial losses because of unexpectedly high plant construction costs and low growth in electricity demand. In addition, the introduction of competition to the electric industry is creating new risks for power companies. No longer will utilities be able to count on regulatory protections and a base of captive consumers to provide a stable market and adequate return on their investments. Alternative risk management strategies will have to be considered instead. One approach to managing risk is for a utility company to invest in diverse power sources such as wind power plants. Since wind plants consume no fuel, can be built in relatively small increments with short construction lead times, and generate no pollutants, it is often said that they offer significant protection from risks associated with conventional fossil-fuel power plants. So far there have been few efforts to quantify these benefits, however. The study compares the costs and risks of two competing resource options, a gas-fired combined cycle plant and a wind plant, both utility-owned, through decision analysis. The case study utility is Texas Utilities Electric, a very large investor-owned company serving an area with substantial, high-quality wind resources. The authors chose a specific moment in the future - the year 2003 - when the utility currently plans to build a large fossil-fueled power plant, and examined the implications for the utility`s expected revenues, costs, and profits if a wind plant were to be built instead.
Date: May 1, 1997
Creator: Brower, M. C.; Bell, K. & Spinney, P.
Partner: UNT Libraries Government Documents Department

Wind Plant Capacity Credit Variations: A Comparison of Results Using Multiyear Actual and Simulated Wind-Speed Data

Description: Although it is widely recognized that variations in annual wind energy capture can be significant, it is not clear how significant this effect is on accurately calculating the capacity credit of a wind plant. An important question is raised concerning whether one year of wind data is representative of long-term patterns. This paper calculates the range of capacity credit measures based on 13 years of actual wind-speed data. The results are compared to those obtained with synthetic data sets that are based on one year of data. Although the use of synthetic data sets is a considerable improvement over single-estimate techniques, this paper finds that the actual inter- annual variation in capacity credit is still understated by the synthetic data technique.
Date: June 1, 1997
Creator: Milligan, Michael
Partner: UNT Libraries Government Documents Department

US Wind Farmers Network

Description: Through this program Windustry representatives have produced, widely used, and distributed new materials and have participated in a wide variety of wind energy events, meetings, and conferences. In this work Windustry representatives have sought to reach a broad audience and grow interest and enthusiasm for wind energy. At the same time, Windustry representatives have sought to provide tools, detailed case studies, and other technical resources that deepen Windustry constituency's knowledge of wind energy options. All of this has served to facilitate development of many actual wind energy projects, particularly projects that emphasize local and community benefits.
Date: April 15, 2005
Creator: Daniels, Lisa & Bennett, DOE Project Officer - Keith
Partner: UNT Libraries Government Documents Department

Short-Circuit Modeling of a Wind Power Plant: Preprint

Description: This paper investigates the short-circuit behavior of a WPP for different types of wind turbines. The short-circuit behavior will be presented. Both the simplified models and detailed models are used in the simulations and both symmetrical faults and unsymmetrical faults are discussed.
Date: March 1, 2011
Creator: Muljadi, E. & Gevorgian, V.
Partner: UNT Libraries Government Documents Department

Active Power Control Testing at the U.S. National Wind Technology Center (NWTC) (Presentation)

Description: In order to keep the electricity grid stable and the lights on, the power system relies on certain responses from its generating fleet. This presentation evaluates the potential for wind turbines and wind power plants to provide these services and assist the grid during critical times.
Date: January 1, 2011
Creator: Ela, E.
Partner: UNT Libraries Government Documents Department

Testing Active Power Control from Wind Power at the National Wind Technology Center (NWTC) [Presentation]

Description: In order to keep the electricity grid stable and the lights on, the power system relies on certain responses from its generating fleet. This presentation evaluates the potential for wind turbines and wind power plants to provide these services and assist the grid during critical times.
Date: May 1, 2011
Creator: Ela, E.
Partner: UNT Libraries Government Documents Department