TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Plant: The vaporizer is integrated in the stack and/or in a housing with the stack. The plant has a heat exchanger through which waste gas from the anode and/or cathode is passed and a gas purifier. The vaporizer also acts as condenser. At least part of one module, a tank and/or a pipe has insulation and/or a local heating element. The plant has supply port(s) that can be collected to a process medium and/or coolant feed pipe. The stack is preceded by a filter. It also has a control unit and analysis unit(s), which is supplied with information on actual measured values and controls the plant be comparison with predetermined and/or calculated ideal values, so that the measured actual values correspond to the ideal values For start-up, the plant is provided with a starter cartridge containing a methanol/water mixture suitable for reaction at the anodes. It also has a hydrogen reservoir.Preferred Process: The waste heat is used in apparatus of the fuel cell plant. Re-usable constituents of the waste gas are recovered and/or recycled. Water and/or methanol is recovered from the waste gas from a direct methanol fuel cell (DMFC) in a heat exchanger, e.g. vaporizer, preheater for process media and/or condenser. The waste gas is passed through a gas purifier. The fuel cell stack operates at 80-300 degrees C. At least part of a module, tank and/or pipe is insulated and/or heated during the stationary phase of the plant. In operation as a DMFC, the operating temperature of the vaporizer is less than that of the waste gas from the stack. During cold starts, hydrogen is fed to the stack as fuel and the waste gas preferably is re-used and/or passed to the gas purifier; and/or liquid fuel and/or fuel from a starter cartridge is fed to the stack. The cooling medium is passed in the same direction during the cold start and reversed to countercurrent flow to keep the temperature profile as uniform as possible after the cold start. The process medium and/or coolant are filtered before entering the stack. The efficiency is optimized by comparing measured actual value(s) with ideal value(s) and using regulator(s) to match these values. The hydrogen reservoir is replenished by electrolysis of water and/or a water-methanol mixture. The second waste heat is used.