Potential rooftop photovoltaic energy production calculation for Residential Buildings in Visby-----Case study about Gotlandshem

Solar energy is one type of the most commonly used renewable energy sources. It can produce electricity and heat without creating any Greenhouse Gases (GHG). Sweden has set up the goal of 100% electricity generated by the renewable energy source by 2040 and chosen Gotland as a pioneer project for self-electricity supply by renewable energy sources by 2030. Taking the year 2017 as an example, the total electricity production of Gotland in 2017 was about 1080 GWh, a share of 621GWh imported from mainland Sweden, 457GWh produced by Gotland's local wind energy, 1.6GWh produced by local photovoltaic energy and a very small fraction produced by local hydropower. Gotland has a high potential for photovoltaic power. This quantitative research case study used data to collect and a building model to measure the potential electricity production by photovoltaic power at three locations in Visby, Höken, Castor and Skalbaggen. Further, an analysis of the current value of installing photovoltaic panels for a public housing company to increase the capacity of renewable energy to stimulate the target towards 100% electricity from renewable energy sources by 2040. The result indicated that the ratio of production/Consumption at Höken, Castor and Skalbaggen were 73%, 52% and 1000%. According to the calculation, the LCOE of Höken is around about 0.74 to 1.17 SEK/kWh. For Castor, it is from 0.73 to 1.16 SEK/ kWh due to the range of interest rates. For Skalbaggen, it is around 0.70 to 1.11 SEK/ kWh. However, since the current limitation from both technical and legislative sectors were not allowed to transfer electricity between the adjacent building. Further research is required on how to facilitate tenants' use of renewable electricity produced by public housing itself, as well as how to maximize the penetration of smart grids