Design of an SOFC for both high internal heat and high electrical power generation at reduced electrical efficiency results in a SOFCR, solid oxide fuel cell reformer. The high-temperature heat is used mainly for internal reforming of natural gas. This new combined production of electrical energy and hydrogen-rich syngas is much more efficient than separate production. The most important applications are the supply of the chemical industry with electricity and hydrogen, and the use for on-site Fewer generation in conjunction with PEM fuel cells. The results of thermodynamic calculations, particularly in the range of low cell voltages, are confirmed by experimental studies and modeling calculations.