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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: 2004-09~
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

Chronological Reliability Model Incorporating Wind Forecasts to Assess Wind Plant Reserve Allocation: Preprint

Description: Over the past several years, there has been considerable development and application of wind forecasting models. The main purpose of these models is to provide grid operators with the best information available so that conventional power generators can be scheduled as efficiently and as cost-effectively as possible. One of the important ancillary services is reserves, which involves scheduling additional capacity to guard against shortfalls. In a recent paper, Strbac and Kirschen[1] proposed a method to allocate the reserve burden to generators. Although Milligan adapted this technique to wind plants[2], neither of these papers accounts for the wind forecast in the reliability calculation. That omission is rectified here. For the system studied in this paper, we found that a reserve allocation scheme using 1-hour forecasts results in a small allocation of system reserve relative to the rated capacity of the wind power plant. This reserve allocation is even smaller when geographically dispersed wind sites are used instead of a large single site.
Date: May 1, 2002
Creator: Milligan, M. R.
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

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

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

Environmental studies related to the operation of wind energy conversion systems. Final report

Description: This biophysical impact assessment explores the environmental consequences of the emerging wind energy conversion technology through field studies done at the DOE/NASA 100-kW Experimental Wind Turbine located at NASA Lewis Research Center's Plum Brook Station near Sandusky, Ohio. A micrometeorological field program monitored changes in the downwind wake of the wind turbine. Horizontal and/or vertical measurements of wind speed, temperature, carbon dioxide concentration, precipitation, and incident solar radiation showed measurable variation within the wake only for precipitation and wind speed. The changes were minor and not likely to result in any secondary effects to vegetation, including crops, because they are within the natural range of variability in the site environment. Effects are negligible beyond the physically altered area of the tower pad, access, and control structures. The wind turbine has not proved to be a high risk to airborne fauna, including the most vulnerable night-migrating songbirds. Behavioral studies indicate the birds will avoid the turbine if they can see it.
Date: December 1, 1977
Creator: Rogers, S.E.; Cornaby, B.W.; Rodman, C.W.; Sticksel, P.R. & Tolle, D.A.
Partner: UNT Libraries Government Documents Department

Siting technologies for large wind turbine clusters

Description: Site selection for large wind turbine clusters requires thorough documentation of the wind characteristics at the site, because of the influence these characteristics will have on the economics, operations, and service life of the wind turbines. The wind prospecting strategy can be used by a utility to determine specific locations for each wind turbine in a cluster of 10 to 50 or more machines. The key to site selection is knowing what and where to measure. Siting techniques to be used at the various stages of the wind-prospecting strategy are discussed. These techniques help determine where to measure. What to measure at a site is still a moot question. Suggestions are made on what data are needed at what sampling rates. These are based on the assumption that until further experience in siting large clusters of wind turbines is in hand, thorough documentation of wind characteristics affecting machine and cluster output characteristics, operation strategies, and service life are necessary.
Date: November 1, 1979
Creator: Hiester, T.R. & Pennell, W.T.
Partner: UNT Libraries Government Documents Department

Reliability of wind power from dispersed sites: a preliminary assessment

Description: The reliability benefit of geographically dispersed wind turbine generators is analyzed. Electricity produced from wind machines experiences wide fluctuations of output at a given site. Yet the value of electricity is a function of its reliability. Pricing schedules have traditionally valued firm power, that is, reliably available power, much more highly than ''dump power;'' that is, power which is available intermittently on an ''if and when'' basis. The conventional wisdom on wind power suggests that it is unrealistic to expect that wind generation will be sufficiently reliable to displace conventional capacity. While such conclusions may be valid for analysis of individual sites, the main thesis of this paper is that geographical dispersal improves aggregate reliability.
Date: April 1, 1978
Creator: Kahn, E.
Partner: UNT Libraries Government Documents Department

14th Annual international meeting of wind turbine test stations: Proceedings

Description: These proceedings are of the 14th Annual International Meeting of Test Stations. As the original charter states these meetings are intended to be an international forum for sharing wind turbine testing experiences. By sharing their experiences they can improve testing skills and techniques. As with all new industries the quality of the products is marked by how well they learn from their experiences and incorporate this learning into the next generation of products. The test station`s role in this process is to provide accurate information to the companies they serve. This information is used by designers to conform and improve their designs. It is also used by certification agencies for confirming the quality of these designs. By sharing of experiences they are able to accomplished these goals, serve these customers better and ultimately improve the international wind energy industry.
Date: November 1, 1994
Partner: UNT Libraries Government Documents Department

Modeling Utility-Scale Wind Power Plants, Part 2: Capacity Credit

Description: As the worldwide use of wind turbine generators in utility-scale applications continues to increase, it will become increasingly important to assess the economic and reliability impact of these intermittent resources. Although the utility industry appears to be moving towards a restructured environment, basic economic and reliability issues will continue to be relevant to companies involved with electricity generation. This paper is the second in a two-part series that addresses modeling approaches and results that were obtained in several case studies and research projects at the National Renewable Energy Laboratory. This second paper focuses on wind plant capacity credit as measured with power system reliability indices. Reliability-based methods of measuring capacity credit are compared with wind plant capacity factor. The relationship between capacity-credit and accurate wind forecasting is also explored.
Date: March 1, 2002
Creator: Milligan, M. R.
Partner: UNT Libraries Government Documents Department