The Swedish energy system is changing and two major events that are taking place are the phase out of nuclear power and the increase of wind power. The associated changes affect the electricity market and the electricity producers, including combined heat and power plants. This thesis evaluates the Swedish energy system of 2025 with focus on electricity spot prices. It also investigates how a combined heat and power plant might perform in the future, given certain changes in the electricity price. Six different scenarios are developed where the electricity price is modified according to findings with regards to the influence of wind- and nuclear power. A model of a combined heat and power plant and a district heating network is created in BoFiT. The scenarios are applied to the model and results are analyzed in terms of heat production, choice of operational mode, merit order and economical performance. Major findings show a more volatile electricity price in 2025. Low price hours (<100SEK/MWh) occur throughout the year, while high price hours (>640SEK/MWh) take place mostly during winter - the season during which the heat demand is at its peak. Results show that the developed electricity prices require much more regulation from the modelled power plant and that the power plant is more adapted to handling high price hours than low price hours. The district heating network is also affected by the volatile electricity prices, and more frequent and greater variations are observed in the merit order. This suggests that in the future, the electricity prices will need to be followed more actively, and that a strategy will need to be developed, allowing for quick adaptation to the prices - communication and cooperation between the different actors in the network will be needed. / Sveriges energisystem är i förändring där avvecklingen av kärnkraft och ökad implementering av vindkraft är i fokus. Konsekvenserna av dessa förändringar kommer påverka elmarknaden och därmed elproducenterna, bland dem kraftvärmeverk. Detta examensarbete utvärderar energisystemet i Sverige 2025 med fokus på elmarknaden. Arbetet undersöker också hur ett kraftvärmeverk kan prestera i framtiden baserat på förändringar i elpriset. Sex olika scenarios har utvecklats där elpriset har modifierats baserat på analysen av vind- och kärnkraftsutvecklingen i Sverige och dess påverkan på elpriset. Ytterligare skapas en modell av ett kraftvärmeverk och ett fjärrvärmenät i BoFiT. Scenarierna implementeras i modellen och resultat extraheras och analyseras baserat på värmeproduktion, val av driftläge, körordning i systemet samt ekonomisk prestanda. Resultaten visar främst att volatiliteten i elpriset ökar till 2025. Låga elpristimmar (<100SEK/MWh) visar sig inträffa under hela året medan höga elpristimmar(>640 SEK/MWh) dominerar under vintern - säsongen där efterfrågan på värme är som högst. Resultaten visar att det förväntade elpriset kräver högre reglering av det modellerade kraftvärmeverket och att anläggningen idag är anpassad för att hantera framförallt höga elpriser men inte låga elpriser. Även fjärrvärmenätet i sig påverkas av volatilitet i elpriserna och mer frekventa och större variationer observeras i körordningen. Detta antyder att elpriserna i framtiden måste följas mer aktivt och att en strategi, som möjliggör snabb reglering för anpassning av elpriserna, måste utvecklas. Kommunikation och samarbete mellan parterna i fjärrvärmesystemet kommer därmed vara av hög betydelse.

Energy company Vattenfall AB has set an ambitious goal in trying to transform their business into a climate neutral and more resource effective company - all within thetime frame of one generation. Through the business concept “SamEnergi” within the heat sector, Vattenfall looks for district heating customers who are willing to sell heat at a price corresponding to Vattenfall’s own production cost. This report examines the change in ordinary heat production in the partially Vattenfall-owned district heating system in the city of Ludvika, Sweden, arising from the delivery of waste heat from a data center to the system. The data center delivers 1 MW heat at 60 degrees Celsius which is lower than the desired temperature in the district heating grid. The change in ordinary heat production is evaluated in four different scenarios where each scenario represents a way to connect the heat source to the district heating grid, so that the delivery temperature to the costumer is not affected. In two of the scenarios, the data center is placed on site of the main heat production units. For all four scenarios, the ability to deliver heat during normal annual fluctuations in flow and temperature in the district heating grid are assessed. Also, in one scenario the effecton a flue gas condenser is considered. The heat production for a normal year is then modelled and simulated using an optimization software called BoFiT, with and without the excess heat. The results show that the 1 MW excess heat is worth between 0,9 and 1,8 million SEK depending on how the heat is delivered. The lowest value of the excess heat source comes from the scenario requiring a heat pump. The other three scenarios yield similar savings on the ordinary production. The best scenario is when the waste heat is delivered together with the main production unit.