PDF《Wind Power Project》

s Wind and Water Power Technologies Office for supporting this research. The authors would also like to thank Charles Newcomb (Endurance Wind Power), Mark Jacobson (NREL), Neil Habig (Iberdrola Renewables), and Randy Mann (Edison Mission Energy) for their reviews and comments on early versions of this manuscript. Any remaining errors or omissions are the sole responsibility of the authors. iv This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. List of Acronyms and Abbreviations BWE Bundesverband WindEnergie (German Wind Energy Association) DOE U.S. Department of Energy GW gigawatt IEC International Electrotechnical Commission kW kilowatt m meter MW megawatt MWh megawatt-hour NPV net present value NREL National Renewable Energy Laboratory O&

M operation and maintenance PPA power purchase agreement PTC production tax credit SAM System Advisor Model v This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Executive Summary As wind power facilities age, project owners are faced with plant end-of-life decisions. This report is intended to inform policymakers and the business community regarding the history, opportunities, and challenges associated with plant end of life actions, in particular, repowering. Specifically, the report details the history of repowering, examines the plant age at which repowering becomes financially attractive, and estimates the incremental market investment and supply chain demand that might result from future U.S. repowering activities. Repowering as defined here includes two types of actions. Full repowering refers to the complete dismantling and replacement of turbine equipment at an existing project site. Partial repowering is defined as installing a new drivetrain and rotor on an existing tower and foundation. Partial repowering allows existing wind power projects to be updated with equipment that increases energy production, reduces machine loads, increases grid service capabilities, and improves project reliability at lower cost and with reduced permitting barriers relative to full repowering and greenfield projects. Repowering first emerged in the early 1990s in the California and Danish wind power markets and was followed by the Dutch and German markets in the 1990s and 2000s. Although repowering activity has occurred elsewhere, these locales remain the principal markets for repowering investments. Historically, repowering has been viewed as a means of increasing project productivity while offering an array of other potential attributes of interest. Fundamentally, however, profitability for a given project is the primary driver of repowering decisions. Given limited financing, the anticipated profitability at alternate greenfield sites is also relevant. Two distinct analyses were conducted to understand the plant age when repowering becomes viable. These analyses utilized NREL'

s System Advisor Model (SAM), a tool that enables the user to predict estimated cash flows from a variety of electric power generation technologies. Net present value calculations were utilized to enable comparisons across time. The first analysis involved creating proto-typical wind plants of four different vintages, with commissioning years of 1999, 2003, 2008, and 2012. Proto-typical plants are representative of the industry at the time of their construction and rely on market data from each of the commissioning years to derive installation and equipment costs, power purchase agreement revenue, net capacity factor, receipt of federal production tax credit payments, and operation and maintenance expenses. For each of these four plants, future investment decisions to repower, or build a nearby greenfield site, were evaluated for 2015, 2020, 2025, and 2030. The second analysis focused on three actual wind plants operating in the United States. These plants were chosen for varying vintages and geographical diversity and include a Northeast wind plant (15C20 years old), a Midwest wind plant (10C15 years old), and a West Coast wind plant (20C25 years old). For these three plants, the decision to repower the current site or invest in a nearby greenfield site was assumed to occur in the 2012C2013 timeframe. Estimated costs to repower, expected revenue, and operational statistics were acquired from nearby sites that were recently placed in service or are in active development. vi This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Both financial analyses concluded that repowering tends to become financially attractive, relative to investing in a nearby greenfield site, after approximately 20C25 years of service. Plants less than