system catches fire anyhow carbon dioxide gas also serves as fire extinguisher in principle any electrically non conducting gas or fluid can be used which is suitable to serve as coolant and which is flame resistant too as for instance an inert gas in case the discharge process is started by closing the first switch 10 the coolant 14 is led to the first discharge resistor 12 this is indicated by arrow 18 in fig1 for an optimal cooling of the first discharge resistor 12 the first discharge resistor 12 comprises a plurality of cooling holes 20 which enable the coolant or simply air to cool the resistor wires of the first discharge resistor 12 the coolant 14 can be led to the first discharge resistor 12 by providing means such as guidance channels not shown in case the coolant 14 as for example co2 is stored under pressure and located in the vicinity of the first discharge resistor 12 such extra providing means are not necessary since opening the pressure tank 16 causes a coolant jet out of the opening of the tank 16 which can be directed towards the first discharge resistor 12 it is further preferable to lead the coolant 14 to the energy storage system 2 as well since the fast discharge process has a heat related impact onto the energy storage system 2 itself a cooling of the energy storage system 2 would allow an even more faster discharge process providing of the coolant 14 to the energy storage system 2 is indicated by arrow 22 for that the coolant 14 can be led through the first discharge resistor 12 and after that to the energy storage system 2 but it is also possible to split.