Geothermal spa and district heating in Topusko
Overview
Topusko is a municipality 70 kilometres south of the Croatian capital Zagreb, located in a region with abundant geothermal resources. In a unique system in the country not only an entire spa complex but a number of public buildings such as the town administration offices, a secondary school, a kindergarten, a church and some apartment blocks are heated with geothermal. In this way the local thermal resource is important for the town both as an enabler of health and recreational tourism and for the decarbonisation of its heating sector.
History
Already in Roman times, Topusko was known for its thermos-mineral water. Three thermal springs existed with temperatures of up to 55°C making them the second warmest springs in Croatia. First exploration drillings to collect data on the aquifer lying under the town were conducted between 1977 to 1985. The thermal water reservoir is located relatively close to the surface, the boreholes are only between 150 and 250 meters deep.
Current geothermal use
The four geothermal wells that are used today, the heat plant and the district heating network are owned and operated by the spa operator, Health Spa Topusko. With a water temperature of 64°C during most of the year, the geothermal heat can be used directly for district heating and domestic hot water, and after that for the spa and therapeutic purposes.
Topusko smart thermal city
Despite this diverse use of the geothermal resource in Topusko, its potential is far from being fully exploited. In the ongoing project “Topusko smart thermal city” the town wants to make greater use of the thermal resource under their feet and develop it in a long-term, sustainable way. The project includes the reconstruction of wells, automation, and the extension of the heating grid to connect more buildings. It is financed by the Iceland, Liechtenstein and Norway within the European Economic Area's 2014-2021 financial mechanism with €604,000. Additionally, Croatia has granted €421,000 within the "Energy and Climate Change" programme.
Summary
Heat supplied to: Spa, therapeutic purposes, public buildings (offices, school, kindergarten, etc.), apartment blocks
Number of wells: 4
Depth of wells: 150 – 250 meters
Temperature: 64°C
Extension of the geothermal system under the ongoing project “Topusko smart thermal city”