Byggnadsteknisk och ekonomisk utvärdering av solceller vid takbyte : Med avseende på korrugerat plåtsadeltak och låglutande platt tak

Sammanfattning: Gräslöken is a tenant-owner association that owns real-estate and controls the electricity usage in certain areas in Årsta – Uppsala. Gränslöken strives for producing electricity by using solar cells, which helps improve their future environmental plans. The facility has a renovation plan that includes roof replacement, which will take place in 2032. Thus, the decision makers in Gränslöken are reconsidering whether it is profitable to install solar cells on their roofs that are to be replaced within 10–15 years. This study aims to suggest the most optimal installation proposals for solar cells on Gräslöken’s roof. It also measures the cost of the investment and analyzes and profitability. In this study, a theoretical design for the solar cells systems is presented, regarding the roof replacement on the corrugated sheet saddle roofs and flat roofs. The investment cost and pay-off period analyses are going to be presented in this study. The profitability analysis is based on the annual production of electricity, plus the electricity cost, in relation to Gräslöken’s annual electricity needs.           The results of the investigation shown considerable possibilities to invest in a solar cells project, both from economical and technical perspectives. As a result of the building-technical study, the decision was taken to install the solar cells only on the corrugated sheet saddle roofs, due to economic reasons, in addition to the necessity for roof replacement. In terms of profitability and pay-off period, the deal is profitable for Gräslöken, even in case of reinstallation of the solar cells, or if the electricity price was fallen. The results of the report show that the pay-off period increases from around 9 to 10.2 years.  The reason of the increase is that the solar cells need to be installed down and back when changing the roof.           This investment in solar cells and renewable energy contributes to Gräslöken’s sustainable development and move forward to reach national environmental goals.