cristi.stoian

Dear Niels, i have a question regarding my method. I have a tower with anemometers at 5 levels: 10/30/60/80/100m. I'm using another software, Windographer, where i can import the measurements from all this 5 sensors, and obtain the Vertical Wind Shear Profile, meaning I've got the value for Power Law Exponent. Next step is to filter all the data, for icing or other errors. Then i can make an extrapolation(simulate the wind) at a higher level, let-s say 120m. This extrapolation(simulation) is made taking into consideration only the measured values from all my 5 anemometers, without knowing the orography. Now i have a new time series, at 120m, obtained using the measured values from all the sensors. With this time series, i go into WAsP and i make the wind atlas at 120m, then i calculate the wind energy at 120m. Beeing a WAsP forum i don't know if it's ok to bring in discussion other software's, but i'm interested to know if you ever used this method and if you have a feedback. Also I'm mentioning I've made a test in Windographer in order to check the simulated values. On a 120m lattice tower, with sensors at 10/30/60/80/100/120m, i used the anemometers from 10/30/60/80/100m in order to obtained a simulated time series at 120m. The difference between the mean wind speed obtained and the measured value from the 120m anemometer was only 0.2%. This was made with 3 months of measurements. Maybe it was interesting to make diferent wind energy calculation using diferent wind atlases ( from the anemometer from 10/30/60/80/100/120m), then calculate the wind energy production at 120m, and compare the results. Thanks for the attention and I'm waiting for some feedback.

i've heard that are some methods to auto download maps from GoogleEarth, EMD has a tool for this, but Google didn't alowed them to put this feature into the commercial version of WindPRO. Do you know anything about the possibility of downloading maps from GoogleEarth?

Because in Romania we don't have digital maps (here digital maps means a simple scan from the paper map with geo-ref coordinates), i do all the work manually. Near the met mast or the wind turbines i'm defining by hand all the height lines, if i have topographical measures i also combined them, then i complete the extended area with the SRTM lines. For the roughness map, i use a combination of GoogleEarth/Global Mapper/Autocad. Because the national/military maps are to old i'm making a grid, then i export this grid in GoogleEarth, i select a squere from this grid, then zoom at maxim, make a screen shot. After i have screentshots for all the squares, i merge the images and i geo-ref them. Then i import this image in Autocad and define the roughness areas. I don't use WAsP Map Editor for this because it's hard to zoom in/out or use other functions for drawing. From Autocad i export everything to MAP Editor, then set the roughness values. Also, with Global Mapper i make an export for Google Earth, with the defined roughness areas, with different hatch for different area type, in order to see everything clearly in Google Earth. It'a a lot of hard work, but i know some wind reports made by others using scaned paper maps, with turbines placed in villages, or in lakes, because they didn't check the GoogleEarth.