Sammankoppling av fjärrvärmenät : Transiteringsledning mellan Borlänge, Ornäs och Torsång

Sammanfattning: Borlänge Energi, BE, owns small district heating, DH, networks in Ornäs and Torsång outside Borlänge, these have high operating costs that are not weighed up by the revenue they make, due to this BE makes a yearly loss on them. Because of this BE wants to connect the small DH networks with the main DH network in Borlänge where the production costs are lower. The technical and economical prerequisites for a connection have therefore been studied. Previous literature has been studied regarding economic parameters for connection of DH networks. Unfortunately, the type of connection that is studied in this report has not been found. The studied literature covers expansion of DH network and connection of larger DH networks, and in most cases, the connecting networks have different owners. Three possible routes were chosen for the connection with Borlänges DH. The current load for Ornäs and Torsång as well as possible new customers was calculated and used to dimension the pipes and calculate the costs for three different scenarios with different loads. Thereafter the costs and incomes from a connection has been calculated, and then used in BEs capital budget where the pay-off time was calculated based on the discounting method. The capital budgets showed that all the routes except one in the base case were profitable within the time frame of 30 years that was set by BE for investments in DH. Sensitivity analyses were made for pay-off time, construction costs and pipe dimension, which showed that the pay-off time is affected by several factors. But was mostly affected if production costs increase or if pipes are dimensioned for a much larger load than what actually is connected in the end. The number of new customers is therefor important to ensure before building the interconnecting pipe. Pipe dimension was affected most by the load as the transition losses are relatively small, and the building costs were affected most by the cost of the DH pipes since they constitute a large part of those costs. Besides from the technical and economical results it has been shown that each and all of the routes have its own prerequisites, where each route has its own pros and cons. All-in-all one route has been chosen as more suitable than the other two, as it besides one of the shortest pay off times also include possibilities to connect new customers along the route. As district heating is dependent on local conditions, in regard to both the technical aspects and the soil composition, the report includes several simplifications and assumptions, which have been made based on local conditions and experience. It is necessary to take this into consideration before attempting to apply the findings of this report in other places than Borlänge.