Improvement of energy efficiency of the auxiliary steam system and rock-cavern storage at Karlshamnverket

Abstract: Goals: Increase the efficiency in the operation of the auxiliary boilers, and the utilization of the rock-cavern storage under a tecno- economic lens. Including in the work is modification and improvement of the plants documents regarding the planning of consumers in the auxiliary steam system. Moreover, is energy saving measures examined in the rock-cavern storage, based on own developed model of its energy losses. Method: A model was developed of the rock-cavern storage, including the piping system down to the storage. Estimations of the energy heat loss, and heating of waterbed was achieved, and based on these estimations where energy saving implementations examined based on the payback method. Conclusions: The energy losses in the rock storage caverns are expected to be somewhere between 07 and 1,1MW depending on the water beds temperature, the water leaking in and the oil level in the caverns. The smallest size of local heating device to accommodate the needs of the plants personnel is expected to be 2MW. The switch to a locally installed electric hot water boiler is expected to save electricity equivalent to about 440 000 to 100 000 SEK per year which equals to an average payback time of around 6,7 years. The modelled pipes that today lead the steam to the storages were calculated to account for about 4% of the total static losses from the steam system.