12th International Symposium on District Heating and Cooling

The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, EstoniaEffects of heat measures in the three heat areasIn the ‗Industry‘ heat area availability of heat measures(electric heat boilers, heat pumps, and heat storages)had relatively little effect (Fig. 2). The main reason isthat the existing heat production capacity fromindustrial wood waste and the associated no-costHeat capacity (MW)Heat production (GWh)2500020000150001000050000BaseOnlyHeatCap.BaseOnlyHeatProd.HEATSTOREL_HBWW_BP_INWR_BP_INPE_BP_INNG_BP_INFO_BP_INFig. 5. Heat capacity and production 8 in the ‗Industrial‘heat area.waste wood were not easily replaced. However, therewere some high wind situations with low power priceswhere it was beneficial to use electric heat boilers toproduce heat and decrease heat production from woodwaste in the ‗Industry‘ area. There was an annualresource limit on wood waste on the country level andthe wood waste use was transferred to the ‗Rural‘ heatarea. It was also profitable to install some heat storagecapacity. This enabled the full shut down of woodwaste back pressure power plants for the duration oflow electricity prices. This decreased electricityproduction and gave more room for the upsurge in windpower production.In the ‗Urban‘ heat area heat measures enabled thereplacement of CHP coal units with production fromheat pumps and to smaller extent from electric heatboilers (Fig. 6). Also wood based heat boilers werereplaced. Investment in heat storage was relativelysmaller. However, they were cycled more due to fastercharging rate.Heat capacity (MW)Heat production (GWh)3500300025002000150010005000BaseOnlyHeatCap.BaseOnlyHeatProd.HEATSTOREL_HPEL_HBNG_HBCO_EXWO_HBNG_EX_URNG_BP_URMW_HB_URMW_BP_URFig. 6. Heat capacity and production 1 in the ‗Urban‘ heatarea.The combined utilization of the heat measures wasused to shut down existing natural gas based CHPpower plants during hours of average or lowerelectricity prices. During low electricity prices electricheat boilers were used to charge heat storage.Accordingly, during average electricity prices heat wasused from heat storage to prevent the use of electricheat boilers. During the highest electricity priceselectric heat pumps were also shut down with the helpof heat from the heat storages.The most important difference between ‗Urban‘ and‗Rural‘ heat areas is the availability of wood residues inthe ‗Rural‘ heat area (Fig. 7). For the most part thisresource was able to outcompete heat pumps asmeans to produce heat. Heat measures still helped toreplace coal CHP. The combination of electric heatboilers and heat storages was again a large source ofadditional flexibility to the system.Heat capacity (MW)Heat production (GWh)120001000080006000400020000BaseOnlyHeatCap.BaseOnlyHeatProd.HEATSTOREL_HPEL_HBNG_HBNG_CC_EXCO_EXWR_EXWW_EXWO_HBWO_BP_RUPE_BP_RUNG_BP_RUMW_HB_RUFig. 7. Heat capacity and production 1 in the ‗Rural‘ heatarea.8 Heat production is from the modelled 26 weeks and should bemultiplied by 2 to get an estimate on annual production.196