12th International Symposium on District Heating and Cooling

to heating costs of 14,5 ct/kWh. The emissions of sucha system are 8,9 g CO 2 /kWh.The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, EstoniaIf the heating amount of the 50 % scenario is used butwithout a storage [scenario 3], and therefore withoutthose losses, a much smaller collector area iscalculated. However, the produced heat has to be useddirectly within a large heating grid. For such a system2542 m² of solar thermal collectors are needed whichproduce 1071 MWh/a. The smaller collector area andthe elimination of a storage system give heating costsof 7,7 ct/kWh. On the other hand the emissions of sucha system are higher because of the necessary pumpenergy for the pressure compensation. The totalspecific emissions of that system are 12,2 g/kWh.Fig 2: CO 2 emissions of different system [1], [5]Under consideration of scenario 4, the heat costs are13,8 ct/kWh within a single family house. If a heatinggrid would be used for storage and therefore no largethermal storage is necessary, the heat costs can godown to about 11 ct/kWh. If the losses of the storagesystem are included in the calculation, a smaller grossarea of collectors can be used. Combining all thosesavings, the heat cost for a single-family house can godown to 7,2 ct/kWh (scenario 5). This shows, that thereis a wide margin and a high potential of cost reductionif a heat grid is used. But it has to be said, that thoseheat costs are still much higher than from other heatgenerating systems.Table 4 shows the technical results and parameters foreach calculated scenario. Based on those figures thefinancial and ecological calculation where made. Thoseresults are shown in Figure 1 and 3. For the renewabletechnologies the increase of 2% of the heat costs caneasily be included in the calculation. For the fossil (andthe biomass) use, the heat price is highly dependent onthe fuel price development. Therefore a price range isgiven on those systems. The reason for the range forfossil CHP heat CO 2 emissions is that differentreferences are used.Table 4: output parameters of simulationscenarioCollector grossarea [m²]Producedheat[MWh/a]Storagesize[m³]1 3080 1076 28202 1916 493,6 175Fig 3: heat costs of different system [1], [20]CONCLUSIONTo make the solar thermal heat production economicalcompared to the other systems, different aspects haveto be changed. In order to show the potential of costreduction for solar thermal heat generation a sensitivityanalyses has been carried out. The followingparameters have been varied in order to reach a heatprices of around 3,5 ct/kWh in the beginning year. Thisis the actual heat price for private customers inMannheim.Future heat price developmentChange of investmentAmount of financial supportInternal Rate of Return3 2542 1071 -4 44 11,6 45 29 11,6 -137