Techno-Economic Analysis of Small-Scale Polygeneration Systems for a Ground Based Air Defence Operations Center in the Swedish Armed Forces

Sammanfattning: Climate change is an important topic of today's discussion where scientists have determined that a large proportion of the increasing global temperatures is a product of the increasing greenhouse gases in the atmosphere. Globally it is expected that the share of renewable power generation is set to increase with 50 % between 2019 and 2024. Together with cost reductions and advancements in renewable energy technologies this opens up an opportunity for companies and market actors to reevaluate their power generation systems. By utilising a polygeneration system an energy system is able to combine multiple energy sources to produce several energy services in an efficient, cost effective and sustainable way. This thesis analyses the possibilities of implementing alternative power generation systems for a unit in the Swedish Armed Forces. In close conjunction with the Swedish Armed Forces works The Swedish Defence Material Administration with the primary assignment to procure, develop and deliver equipment and services to the Swedish defence. In this thesis, a Ground Based Air Defence Operations Center is used as a case study which utilises diesel gensets for power generation. The energy system of the unit is analysed as well as the power, heat and cooling demands. Different scenarios based on current and future developments in energy technology are modelled in the microgrid software Homer Pro. The system model 1 for the scenarios BAU, AF1 and AF2 requires no modification of the gensets in the current power generation system. Instead alternative fuel types are modelled where a biodiesel B20 blend is used for AF1 and 1 hydrogenated vegetable oil is used in the AF2 scenario. In the scenarios using the system model 2, FS1 is utilising the current genset upgraded with a heat recovery system running on hydrogenated vegetable oil. The FS2 scenario proposes a microturbine with a capacity of 30 kW as an alternative to the current genset. In the FIFS scenario a PEM fuel cell is modelled, also having a capacity of 30 kW. All of the system model 2 configurations included a battery system, a membrane distiller for water purification and a thermal storage tank as additional units. The main results from the thesis show that all scenarios except for FS2 reduce the annual emissions from the unit. However, this brings a higher net present value for the systems as well as a higher yearly operation cost. The results indicate that the FS1 scenario is able to decrease the CO2 emissions with almost 50 % with adjustments to the current gensets as well as providing the unit with excess heat for water purification and storage in the thermal tank.