Climate impact and cost savings of implementing fossil-free heating and PV-system : A case study of a school building in Sweden

Uppsala municipality has in their climate vision stated that all oil based heating should be phased out prior to the year of 2020, with the objective to reduce the use fossil fuel and make a way for renewable energy sources. Uppsala municipality has also the ambition to have 100 MW installed solar energy by 2030. This project is a case study on the climate goals stated above, performed at Knutbyskolan. Knutbyskolan made a replacement of boilers in their heating system. The purpose of this study is to evaluate this in terms of fuel costs and emissions of CO2-equivalents. The potential of installing a PV-system is also investigated. The result regarding the evaluation of the boiler replacement indicates a positive outcome, where costs and especially emissions of CO2-equivalents have been significantly reduced. Annually, the cost and emission reduction is estimated to be 13% and 55%. The result is based on a normal year correction by using degree days to make the fuel consumption statistical comparative. The investigation of the potential in different PV-solutions was simulated in MATLAB and evaluated in terms of self-consumption and self-sufficiency. Two different sizes are tested with different tilts. The first case is a system of 40 m2, which covers 12.5% of the yearly electrical consumption. This resulted in a self-consumption of 99% and a self-sufficiency of 13%. In the second case the system is 350 m2 in order to maximize the electricity production.This resulted in a self-consumption of 44-46% and a self-sufficiency of 50%