TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Component: The jet pump has a single utilization design condition. The fuel cell system further comprises a flow control device in the fuel delivery line to the jet pump, where the flow control device may be adjusted in order to control the proportion of fuel entrained by a given steam flow rate through the jet pinup so that the steam to carbon ratio in the gas stream may be controlled. The flow control device comprises in series a zero governor and a needle valve. The jet pump has a variable nozzle area geometry that is adapted to control the cross-sectional area of a jet of steam on entry into the jet pump. The jet pump comprises a nozzle, an entrainment chamber downstream of the nozzle and a mixing tube downstream of the entrainment chamber, where a delivery line for the gaseous fuel opens into the entrainment chamber for supply of gaseous fuel thereto, and where a mass flow control device is provided in a line for delivering steam to the jet pinup to control the flow of steam to the jet pump. A proportional control valve (12) is included in the fuel delivery line to the jet pump, where manipulation of the valve restricts the proportion of fuel entrained by a given steam flow rate through the jet pump so that the steam to carbon ratio in the gas stream may be controlled. The steam reformer is a steam pre-reformer and the fuel cell assembly is capable of internal reforming of hydrocarbons at the anode. The steam generator delivers steam to the steam inlet of the jet pump at 150-1000degreesC and at a pressure of 5 kPag to 50 MPag. The fuel cell system is rated at 1 kW and the steam generator has a steam output of 500g/hour. The steam reformer is a steam pre-reformer and the fuel cell assembly is capable of internal reforming of hydrocarbons at the anode thereof. Steam pre-reforming is carried out such that the methane content of the fuel stream to the fuel cell assembly is adjusted based on prevailing load characteristics and on the prevailing cooling requirements of the fuel cell system.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The gaseous hydrocarbon fuel exerts a fuel pressure at the inlet to the fuel inlet of the jet pump of zero or essentially zero. The source of hydrocarbon fuel is a relatively high pressure source and the hydrocarbon fuel is delivered to the jet pump via a delivery line (3) that includes a flow control device to reduce the fuel pressure at the jet pump inlet to zero or essentially zero. The source of hydrocarbon fuel is a bottled/liquefied source or main supply gas. Preferred Parameter: The maximum pressure at which the gaseous hydrocarbon fuel is provided at source is 1.1 kPa.