The use of expansion engines for the reduction of pressure and the gen
eration of electrical energy has stood the test well. In order to rece
ive more exact data, enthalpy entropy diagrams for different natural g
as combinations were drawn up, as well as several pressure expansion s
tages were compared with each other from a thermodynamic point of view
. Finally, as an example, an expansion plant of about 380 kW electrica
l output was discussed briefly from technical and Economical aspects.