The invention is directed to a turbine having a turbine housing or casing. The turbine housing includes a carrier ring and a ring contour component which is fastened to the carrier ring. The ring contour component has a circumferential flange with which it bears against an annular end face of the carrier ring. At least one hold down is provided which enables the flange of the ring contour component to be releasably fixed against the end face of the carrier ring. The turbine is configured to be part of a micro gas turbine in a combined heat and power cogeneration system.