A fuel
cell system (1000, 1000', 1000'') for providing a
power output (PO), comprising: - a fuel
cell (100) for generating an amount of energy (E, EE, ET) for the
power output (PO) and - an
energy storage device (300) for storing an amount of energy (E, EE, EM), - a control device (400, 400', 400'') for controlling the fuel
cell (100), which is designed to specify a power specification (LV) for the fuel cell (100) for controlling the
power output (PO), wherein - an efficiency (WG) is assigned to the fuel cell (100) as a function of a fuel cell power (PB), wherein - for efficiency-improved operation (BPA), the power specification (LV) is dependent on the
state of charge (LZ) of the
energy storage device (300), and - the power specification (LV) for the efficiency-improved operation (BPA) is determined,when the
state of charge (LZ) of the
energy storage device (300) is above a lower
state of charge (LZL) and / or below an upper state of charge (LZH), characterized in that - for the control device (400, 400', 400''), value information on the efficiency (WG) is provided as a characteristic curve (KL) depending on the fuel cell power (PB), and - for the efficiency-improved operation (BPA), the power specification (LV) specifies a reduced fuel cell power (PA), which corresponds to an increased efficiency (WG) according to the value information, namely the power specification (LV) specifies a reduced fuel cell power (PA) compared to the full (100%) relative nominal power (PREL) or current (<100% PREL) power such that the efficiency (WG) is increased according to the value information compared to the efficiency at nominal power (PREL) or the current efficiency,wherein- an adjustment amount (PAN) of the reduced fuel cell power (PA) depends on the state of charge (LZ) of the energy storage device (300), and- the power specification (LV) for the efficiency-improved operation (BPA) is determined in such a way that a target energy quantity (EZZ) required to achieve a target state (ZZ) for a future forecast period (TP) results from the power specification (LV) and the state of charge (LZ) of the energy storage device (300), wherein- the power specification (LV) is determined in such a way that the target energy quantity (EZZ) is determined as a function of a forecast power profile (PLP).