KALIF-HELIA is a TW pulsed power generator based on the high energy linear induction adder principle. For the nominal 95kV charge voltage of the Marx generator an electrical pulse was expected with a fwhm of 50ns, a peak voltage and -current of about 5.5MV and 400kA respectively. Depending on the switch-out voltage of the PFL water switches a total energy from 123 to 128kJ at a 15W load should be available. For negative polarity operation and for all parameters investigated during an optimization campaign the measured beam energy never exceeded 70kJ. In this paper the measurements performed will be described, optimization results will be summarized, possible reasons for the low energy output will be discussed and finally countermeasures will be suggested.