Steam system calculations must demonstrate that process steam will be available under all conditions of power generation. Loss of GTGs and associated heat recovery systems must not jeopardize the process. In particular, variations in the steam demand profiles and the electrical power demand profiles must be scrutinized to ensure that sufficient contingency exists to make up any shortfall during normal steady-state operating conditions. Also, the steam systems must be designed with sufficient steam retention and make up capability to cater for power system transient disturbances, such as loss of GT driven generators supplying exhaust heat recovery systems.