Fossilfri Fjärrvärme : Möjligheter till konvertering av fossila spetslastpannor hos Falu Energi och Vatten

Sammanfattning: After the Paris climate agreement, the requirements were raised on the district heating sector in Sweden to eliminate the fossil fuels from the production. This concerns mainly the peak load production during cold season when the fossil boilers are needed the most. To get rid of the peak load production of fossil fuels, it is necessary to find an alternative way of producing the heat that still fulfill the requirements on the boilers. You often need to have a flexible load control and a quick startup of the boiler. It is possible to convert a fossil boiler to be able to use bio oil or bio diesel, more or less keeping the same properties of the boiler. The requirements on the system in such a conversion is dependent on the fuel and its properties. In this study the definition of fossil free district heating refers to only the fuel used for production. "Falu Energi och Vatten" (FEV) is a district heating company in a town called Falun in Sweden. They use approximately 3 % fossil fuel (liquefied petroleum gas and heating oil 1) of the energy used for district heat production and have the ambition to be fossil free. The district heating grid in Falun has been studied to examine the economic consequences of a conversion of fossil boiler for peak load production. The technical requirements that leads to economic consequences have also been studied. By studying literature and contacting some technology providers, fuel providers and other heat producers the costs that will be affected by the conversion has been obtained. Three different fuel choices in a boiler conversion have been studied; MFA, RME and HVO. To evaluate the economic consequences, a Life cycle cost analysis (LCC) has been used. Apart from the three different choices of fuel, an LCC has also been calculated for a scenario where you keep using fossil fuels. A sensitive analysis has also been made where different energy demands, prices for energy and the cost of capital have been studied. The results show that all the different choices of bio fuels studied for a conversion is more expensive than keep on using the fossil fuels for FEV. MFA has the lowest LCC, but the largest investment. The price for HVO and the taxes when used for heating makes it substantially more expensive than the other fuels. The sensitive analysis shows that the price of energy and energy demand in the future is crucial for the economic consequences. These must change substantially if the investments are to be considered profitable during the calculation period of 10 years. MFA has a lower LCC the greater the energy demand is for FEV in the future. RME has a lower LCC the lesser the energy demand is. It has emerged that the necessary measures and costs for a conversion of boilers differs a lot depending on local pre-conditions of the boilers and the storage of fuels. The calculations are based on several assumptions making the results uncertain and should be handled with caution. The results are also specific to the conditions of FEV which should be considered before the results can be applied under other circumstances.