German/American wind firm Tacke Windenergie is developing a prototype 1.5 MW machine, the TW 1.5sl with a rotor diameter of 77 metres, for a wind-biogas combined heat and power plant for the Expo 2000 world trade exhibition, to be held in Germany in June. The biogas plant will power the unit-type combined heat and power plant, expected to be in operation this month at Kronsberg near Hannover, according to Ubbo de Witt of wind planning company Projekt. The TW 1.5sl machine will not be installed until late this year or early 2000, de Witt adds. The power plant is an official Expo 2000 project. Power will be fed into the grid of Stadtwerke Hannover. Tacke is also to release a 2.0 MW in 2000, according to Mary McCann of Enron Wind, Tacke's American owner.