Combined heat and power apparatus

A combined heat and power apparatus comprising a gas turbine (34) driving electrical power generating means (60), a boiler (2) comprising heating gases passage means (10,16,22) to receive and convey hot heating gases therethrough whereby heat exchange takes place between said heating gases and water (6) in the boiler (2) to raise the temperature of said water, characterised in that the gas turbine (34) has a power output which does not exceed 0.5 Megawatts, said gas turbine (34) is mounted on said boiler (2) at an inlet end (32) to said heating gases passage means (10,16,22) so that hot products of combustion constituting exhaust gases from the gas turbine (34) are fed substantially directly from a gas turbine exhaust gas outlet end (40) into said inlet end (32) of said heating gases passage means (10,16,22) so that heating gases comprise at least in part said exhaust gases when the gas turbine (34) is operating, fuel gas burner means (68) is disposed in said heating gases passage means (10,16,22) at or adjacent to said inlet end (32) thereof, and exhaust means (26,72) is provided to create a pressure drop along said heating gases passage means (10,16,22) towards an outlet end (28) of said heating gases passage means (10,16,22) to draw the heating gases towards the outlet end (28) of the heating gases passage means.