A method for energy conversion from pressure energy into electrical energy uses an expansion turbine. In the method, a pressurized, gaseous, first medium is heated before being fed into the expansion turbine. The expansion turbine drives a generator and a compressor. At least one gaseous second medium is compressed by the compressor in a heating arrangement. Heat generated by the compression and preferably also via utilization of ambient heat according to a heat exchanger principle is used for heating the gaseous first medium.