Techno-economic assessment of grid-connected photovoltaic systems in Swedish public buildings

Sweden aims to achieve near-zero non-renewable energy use in all the newly constructed buildings from 2020. One of the most promising methods of achieving these energy goals and reducing the net energy-use is using solar photovoltaic (PV) systems in buildings. Although some studies have demonstrated this method, the solar PV industry is growing rapidly. Therefore, the study aimed at using sources with the latest information to analyse the true potential of PV systems for the current initial cost of the PV system and tax benefits in Sweden. The study investigates the economic feasibility of a grid-connected solar PV system from a technical and economic perspective for a group of public buildings in Sweden. The hourly energy production and cost of purchasing deficit electricity was simulated for various tilts and ground coverage area to find the optimum tilt and ground coverage ratio of PV panels. The PV energy supply of four different systems – 26 kWp, 75 kWp, 80 kWp, 155 kWp – in different locations was simulated. The overproduction, own usage rate, solar fraction, investment cost, profit over its lifespan and the payback period of each system were compared for the existing as well as improved energy use. Honeybee 0.0.64 and SAM 2018.11.11 was used to simulate energy use and PV production. Results indicate that a system with a high own usage rate and specific yield was profitable when the selling price of electricity (excluding tax refund) was lower. However, a system with a higher production potential became more profitable when the selling price of electricity (including tax refund) was equal or higher than the purchasing price. Additionally, a sensitivity analysis was conducted to demonstrate the feasibility of the system if the price of electricity or interest rates changed in the future. The outcome of this research demonstrates the techno-economic feasibility of implementing a solar PV system in Sweden and provides a set of benchmarks for comparison of such systems around the world.