Assessments of Wind Power Potential Using NewMeteorological Archives and Doppler SODARMeasurements: Strategies and Experience

摘要

There have been several past studies and compilations of wind power potential, such as the WindrnEnergy Resource Atlas of the United States produced in the mid 1980s. Limitations in windrnmeasurements are critical to assessments of wind power potential because the wind powerrnavailable is proportional to the cube of the wind speed. Therefore, gaps in the database orrninterpolations and extrapolations from widely separated wind observations in time and space canrnhave significant consequences.rnIn recent years, especially since the late 1990s, the amount and resolution of meteorological datarnhas increased and improved dramatically. Today, special software is used by the NationalrnCenters for Environmental Prediction that incorporates and quality-assures a much larger varietyrnof sources of wind data and assimilates the data to horizontal grids with resolutions of 20-40rnkilometers or less with numerous levels in the vertical. The data set is used as thern“initialization” meteorology (observed and quality-assured) for performing weather forecastrnmodeling. The RUC (Rapid Update Cycle) weather model employs sophisticated short-termrnweather data assimilation and forecast tools that combine forecasts from the recent past withrnupdated meteorological data readings. More importantly, the RUC model incorporates newrnsources of data in addition to the hourly surface observations and twice-daily balloon soundingsrnused in more traditional data sets, such as:rn? satellite derived-wind and temperature data;rn? Doppler radar that provides newly available wind data in three dimensions from several radarrnsweeps each hour, extending well offshore near coastlines;rn? wind profilers that probe the atmosphere vertically; andrn? aircraft ascent-descent reports, newly available from several hundred commercial flights perrnday in the U.S.rnThis paper shows that in comparison to wind tower measurement sites in North Dakota, the RUCrnmeteorological data provides more accurate (and higher) estimates of wind power potential thanrnthat obtained from traditional data.rnAWEA GLOBAL WINDPOWER 2004 Conference Paper 2rnOnce a regional assessment of wind power potential is completed using numerical modeling,rnmicro-siting assessments usually require site-specific meteorological measurements. For micrositingrnstrategies with wind turbines that exceed the height of standard 50-m meteorologicalrntowers, it is highly recommended that some wind measurements occur at and above hub height.rnThis is important due to periods of nocturnal wind shear that can feature to near-calm winds nearrnthe ground, but much higher winds at hub height. To take these measurements without thernbenefit of very tall and expensive meteorological towers, a ground-based, remote-sensingrnDoppler SODAR can be used, even in a short-term measurement campaign. However, the use ofrnDoppler SODARs in wind energy assessments is not often done because of the lack ofrnexperience with this remote sensing instrument. This paper summarizes a comparison betweenrnSODAR and conventional 100-m tower measurements at 9 sites throughout the United States,rneach of which was maintained for a full year. The comparison clearly shows that if properlyrnsited and operated, the Doppler SODAR can be a very useful tool for micro-siting wind energyrnassessments.