Energi Intelligent is a program in Dalarna County with the purpose of finding ways of enhancing the efficiency of energy use and thereby be able to reach a more sustainable use of energy resources[1]. The basis of this program is the energy goal that has been prepared for Dalarna County published in Dalarnas miljömål[2].  The energy goal is divided into a number of intermediate goals, the sixth, Delmål 6, is to reduce energy consumption in buildings with 50 percent until 2050, and with 30 percent until 2025[3].   There are often a large number of different sectors involved that have got differing opinions and intentions. This makes the task far more complex than simply reducing energy consumption, because energy efficiency is one goal and that would mean that power companies would not be able to continue increasing their profit.   The aim of this project was to analyze the effects on energy production when reducing the use of heat demand in buildings until 2050. The district heating systems constitutes the main part of heating of buildings in the county and that is why it has been analyzed in this project.  The simulation tool that was suggested in the declaration of the thesis work was LEAP, the Long range energy alternative planning system tool for simulating different scenarios over years from the base year of the model.  The idea was to build energy models of Falun district heating system and Borlänge district heating system in LEAP. Scenarios were defined for the energy goals and then simulated in a model of district heating system. Simulation of the district heating systems were made from the scenarios; reducing the district heating production with 30 percent until 2025 and 50 percent until 2050. The results from the analysis showed that for Falun district heating system the reduction of district heat demand will lead to decreased heat and electricity production and there will be no need for further investment. In Borlänge district heating system capacity is lower than the total capacity of all the available waste resources and there have been discussions about investing in a third municipal waste incineration boiler that would increase the total capacity so Borlänge district heating system could have waste incineration that covers the resources of the fuel cost favorable municipal and industrial waste.