12th International Symposium on District Heating and Cooling

Table VII. – Results for the scenarios – environmentalaspects.Sc.Biomassshare inthesystemLECO 2% [milliontons/year]1 48 2.50 0.322 52 2.25 0.063 49 2.46 0.23GECO 2 ofthe system[milliontons/year]4 52 2.12 – 0.695 55 1.91 – 1.0867 100 0 – 6.0789 0 7.80 – 8.98The income from the electricity sold in scenario 3 isabout 30 million € higher then the income in scenario 1,and because of that the system cost is 6% lower. Thedifference between the electricity production inscenarios 1 and 3 is not significant, but in spite of that,the decrease of GECO2 of the system in scenario 3 isalmost 100%. The reason is higher biomass share inthe total fuel used in the system in scenario 3, andconsequently lower LECO2 in the system.The introduction of three new plants in the system(scenario 4) would lead to a significant reduction of theheat production cost compared with the system today.The income from the electricity sold would be 35%higher and, as a result, the annual system costs wouldbe 20% lower. This confirms that heat production inCHP plants has a major influence on the economicefficiency of the district heating system. With theassumption that the electricity produced would replacethe marginal electricity in the European electricitymarket, reduction of GECO2 of the system would bealmost 1 million tons annually.If all plants in the system are BCHP (scenarios 6–8) orNGCHP (scenario 9) plants, the annual electricityproduction would be as high as 4.5% and 12% of thetotal electricity production in Sweden, which was about145 TWh in the year 2008 [1]. The annual income fromthe electricity sold in those scenarios is much higherthen the income from the electricity sold in the otherscenarios. In the scenarios with typical Europeanelectricity price, (scenarios 7–9), the income from theelectricity sold is 220%, 90% and even 420% higherthen in scenario 3, where the system with the existingplants is analysed with the higher electricity price. It isThe <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, Estonia292also notable that in scenarios 6, 7 and 9 the annualincome from electricity is higher than the annualsystem costs. However, since all plants in thosescenarios are new, the total investments are high.Because of that, if the analysed time period is just10 years, the annual system costs are much higherthen today.The lowest GECO2 of the system are in the scenarioswhere all plants in the system are BCHP (scenarios 6-8) and NGCHP (scenario 9) plants. In those two casesGECO2 in Sweden, which is about 60 million tonsannually [21] would be reduced by approximately 9%and 15% respectively, with the assumption that theelectricity produced would replace the marginalelectricity. LECO2 in the system is highest in thescenario where all plants are NGCHP but at the sametime GECO2 of the system is lower because of the highelectricity production.5. RESULTS FROM THE INTERVIEWSIn the following section the results from the interviewswill be presented. The interconnections between thesystems make it possible to cooperate regarding heatproduction and distribution.5.1 The system todayThe interviews show that the interconnections have ahistorical background. Most of them were made duringa period when a regional energy company calledSTOSEB (Greater Stockholm Energy Company)existed, where the municipalities, which to a largeextent owned the systems then, were represented. Themain reason for the interconnections then was supplysecurity. When the systems were interconnected, thecompanies could help each other during stops, and thisis still the case. All representatives say this, and therepresentative from Söderenergi expresses it this way:…At the same time it is a common good. It is good thatthe systems are interconnected. It is an extra security ifone plant should stop for some reason [22].The advantages historically and foremost today arealso economic. The emissions trading makes itadvantageous, since the companies can use theproduction better by making ―capacity trades‖ and evenout the production cost between the companies:We see that we can use existing production moreeffectively. Most of the trades are a trade to mid-priceso to speak. You can say that we split the profit.Capacity trading (effektköp) is also common. Like wehave here with Söderenergi, we have partlya production cooperation and partly we buy capacity.They have more capacity than they need today [23].