This part of IEC 62282 covers operational and environmental aspects of the stationary fuel cell power systems performance. The test methods apply as follows: – power output under specified operating and transient conditions; – electric and thermal efficiency under specified operating conditions; – environmental characteristics; for example, gas emissions, noise, etc. under specified operating and transient conditions. This standard does not provide coverage for electromagnetic compatibility (EMC). This standard does not apply to small stationary fuel cell power systems with electric power output of less than 10 kW which will be dealt with in the future IEC 62282-3-201. Fuel cell power systems may have different subsystems depending upon types of fuel cell and applications, and they have different streams of material and energy into and out of them. However, a common system diagram and boundary has been defined for evaluation of the fuel cell power system (see Figure 1). The following conditions are considered in order to determine the test boundary of the fuel cell power system: – all energy recovery systems are included within the test boundary; – all kinds of electric energy storage devices are considered outside the test boundary; – calculation of the heating value of the input fuel (such as natural gas, propane gas and pure hydrogen gas, etc.) is based on the conditions of the fuel at the boundary of the fuel cell power system.