engleski

Impact of the Heat Power on the Unit Geothermal Energy Cost

There are in Croatia 28 geothermal reservoirs in total, among which only 14 are beeing used. These are low-temperature resources having geothermal water temperature less than 100oC. Accordingly, geothermal heat on these 14 locations is directly used only for swimming pools, bath and heating purposes. The heat power amounts to 42 MWt, while the percentage of utilization of their available power is less than 50 %. Better usage of installed power can be obtained by cascade processes, which can be thermodynamically divided in two parts. The first power increasement is realized by optimal water flow at the geothermal well-head. The second aims to reach the maximum temperature difference in the heat exchangers, supposing the outlet temperature of 20oC. If the heat on the existing locations is optimaly utilized, the total power could be raised for more than 300 percent, resulting in 140 MWt. Regarding the unit cost of direct geothermal energy usage, the final price could be expected three times lower. However, the results of wide researches show that the power and the unit energy cost on the same geothermal reservoir are not directly proportional, as they follow the law of scale effect.

geothermal energy; techno-economical analysis

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