LCC of a possible expansion of the district heating network in Falun.

This work has been carried out on behalf of and together with Falu Energi och Vatten. The purpose of the work was to study under what circumstances it´s economically profitable to expand the district heating network to residential area with electrical heating compared to keep it as it is today. The expansion of the district heating network will also be simulated to investigate if the existing dimensions of the network are big enough to provide enough heat after the expansion. In this work three different areas in Falun city area has been studied. Two areas (Ritar-, and Skrivarvägen and Digertäktsvägen) where there is no district heating today, and one area (residential district Haraldsbo) where a part of the area is connected to the district heating network and some are not. The study has been performed under the assumption that the production in the facilities are sufficient for providing also the new areas with heat without any need of new facilities. Another limitation that has been set is that only fuel costs will be taken into account in the production costs for district heating. From the calculations of the net present value for the three different areas with expansions of the district heating system, compared to the calculations of the net present value of keeping it as it is today showed that Ritar-, and Skrivarvägen will need to have at least 30-35% households connected to have the same or higher net present value. The corresponding values for Digertäktsvägen is 35-45% connected households and för Haraldsbo around 15% connected households. It was also examined how the connection rates influenced the prize for the households, if the net present value was going to be equal or bigger than for the present situation without any connection cost. It was found that for Harladsbo where there already are some households with district heating only 15% of the today not connected needed to sign up for district heating and in the areas that does not have any district heating today (Ritar-, and Skrivarvägen and Digertäktsvägen) 50-70% needed to sign up for district heating. “Falu Energi och Vatten” calculations today demand a payback time of 12 years of the investment in the district heating infrastructure. To get that 30 -40% needed to connect in Ritar-, and Skrivarvägen and Digertäktsvägen, on Haraldsbo the connection rate had to be over 15%. The results from the simulations made on the district heating infrastructure showed that on Ritar-, and Skrivarvägen the network is sufficient to supply the whole area with heat at the dimensional outdoor temperature of -23°C, also with 100% connections on Haraldsbo the pressure difference, flow speed and pressure gradient are within the permitted span. Simulations of Haraldsbo showed that with a connection rate of 100% the pressure difference got to low in one corner of the area. If the connection rate instead is 50% at Haraldsbo the area manage to keep the pressure difference at an approved level of 160 kPa, if we then also connect 100% at Ritar-, and Skrivarvägen, the pressure difference sinks down to 100 kPa which is the absolute lowest that is permitted