A method and device for converting thermal energy from carbonaceous raw materials into mechanical work is provided. The device includes at least one first and one second device for storing and releasing thermal energy connected at least intermittently alternatingly in a turbine branch having a gas turbine connected downstream. The method includes the steps of: a) combusting a gas in a gas burner; b) passing the smoke gases arising in the gas burner through a device for storing thermal energy; and c) feeding the hot air released by at least one device into the gas turbine, wherein the gasification of the carbonaceous raw materials takes place in a gasifier in a first step and the product gas is fed into the gas burner connected downstream of the gasifier.