Das Projekt "Windenergie fuer die Belueftung eines Klaerwerks in Lemwerder" wird vom Umweltbundesamt gefördert und von Messerschmitt-Bölkow-Blohm durchgeführt. Objective: Demonstration of the aeration of a sewage plant at Lemwerder -Niedersachsen with wind turbine and/or diesel system. Single bladed wind turbine of Monopteros 20 KW type will provide energy during the windy days to a 11 KW aeration of a sewage system. A diesel system will be connected later in order to create a commercial fully autonomous system. Estimated energy production: 40,000 KWh/year at 5,3 m/s mean windspeed. General Information: A Monopteros single bladed 20 KW type downwind windmill of MBB will be installed to provide energy to the 11 KW aeration system of an existing sewage plant. The operating windspeed range for the windmill is 5 to 18 m/sec. For the selected site, where the annual mean windvelocity is 5,3 m/sec, the annual yield is estimated at 40,000 KWh, while the yearly energy consumption of the aeration system is about 48,000 KWh. Auxiliary energy will be provided by a 15 KW diesel system which will also provide the necessary energy during the windless periods, or the periods when the wind exceeds the cut-out speed. Thus the whole system will become autonomous. The cost of the WEC + diesel system is 90,000 DM with a goal to be reduced to about 65,000 DM. The final cost of the produced energy will be 0,978 DM/KWh while the conventional cost is 0. 25 DM/KWh. It is remarkable that the conventional cost is strongly dependent on the distance of the installation from the grid, as the connecting costs varies from 20 to 100,000 DM. Therefore such an autonomous system could be recommended either for islands with high cost of produced energy or for remote areas. Achievements: Due to operational difficulties of the wind-diesel system the demonstration phase has not been fully completed. The system worked only in principle. During a six months operation period there were problems with the wind turbine, the wind-diesel governer and the diesel generator.