Batterilagring i elintensiva fastigheter som verktyg för ett mer hållbart elsystem : En simuleringsbaserad analys av effekttoppskapning och ökad egenanvändning av solel

Sammanfattning

This thesis has examined the potential of battery energy storage in three public buildings in Karlstad, Sweden, with the aim of reducing power peaks, increasing self-consumption of solarenergy, and analyzing both economic and environmental impacts. By developing five differentsimulation models in Simulink, each with varying control strategies and battery configurations,the study has identified how battery systems can be utilized for local energy management. The results show that for peak shaving, Battery Model 2 performed best, as it allowed chargingfrom the grid during periods of low demand. Depending on battery size and the peak-shavingthreshold, this model reduced the number of power peaks by 10 to 30%. It also achieved betteryear-round utilization of the battery compared to the other models. Battery Model 1, which only charges the battery using surplus solar power, increased selfconsumption of solar energy by up to 11%. In contrast, Battery Model 3, which prioritizes peakshaving with solar energy, led to a significant decrease in direct self-consumption. This highlights the importance of selecting a control strategy based on specific system goals. The economic results show that Battery Models 1 and 2 reduced the cost of purchased electricityby approximately 2% due to increased self-consumption. However, this also led to a reductionin income from selling surplus solar electricity to the grid. The environmental analysis indicates that if emissions from battery production decrease asprojected, and the SE3 electricity mix maintains its current climate profile, the climate impactof the battery can be offset through reduced reliance on grid electricity. Depending on batterycapacity (25–100 kWh), the climate payback time is estimated to be between 3 and 10 years. In conclusion, battery storage systems in building-connected grids have the potential to play akey role in future energy systems. To maximize the benefits, careful sizing, appropriate controlstrategies, and adaptation to the building’s unique load profile are essential. The results of thisstudy can serve as a decision-making basis for property owners, municipalities, and energycompanies seeking to invest in sustainable and resilient energy solutions.