Heating in buildings and industries accounts for over 50% of global energy demand and is a major source of greenhouse gas emissions. Geothermal energy offers one of the cleanest and most reliable renewable options for both heating and electricity generation. However, in many regions, geothermal resources are either unsuitable for power generation or require deep and costly drilling to reach sufficiently high temperatures. The GeoSUSTAIN project – a collaborative project between researchers in Canada, Norway, Sweden, the Netherlands, and Austria aims to develop and optimize medium-depth geothermal systems (<1,000 m) that use enhanced borehole heat exchangers (BHEs) to extract heat (at 20-50°C depending on the geographical location) from the subsurface. This heat can be transferred directly to the community (industrial plant, district heating) if the temperature level is sufficient to fulfill the process requirements. If the temperature is not sufficient, the extracted heat is transferred to a heat pump, which can raise the temperature to 80-110°C to cover a wide range of processes. If required, the heat from the heat pump can be stored in a solid media thermal energy storage (SMTES) at 80-110°C and transferred to neighbouring communities via a local district heating and cooling network (DHCN) (4th or 5th generation). The surplus/waste heat from the community can also be fed into the geothermal wells in the summer to improve the sustainability of the system in the long term. The geothermal system, integrated with a heat pump, will also enable efficient cooling delivery to the community, providing year-round thermal management.
