{"id":1474,"date":"2023-06-26T15:52:33","date_gmt":"2023-06-26T13:52:33","guid":{"rendered":"https:\/\/geser.eu\/?page_id=1474"},"modified":"2026-07-22T15:08:38","modified_gmt":"2026-07-22T13:08:38","slug":"what-is-geothermal-energy","status":"publish","type":"page","link":"https:\/\/geser.eu\/en\/what-is-geothermal-energy\/","title":{"rendered":"What is geothermal energy?"},"content":{"rendered":"

Geothermal Energy Simply Explained: What Is It and How Does It Work?<\/strong><\/h1>\n<\/div>

Geothermal energy<\/strong> is heat stored in the Earth’s interior. The Earth’s core reaches approximately 6,000 \u00b0C<\/strong> \u2013 and even at shallow depths, the ground maintains a constant temperature of around 8\u201312 \u00b0C year-round. This natural, renewable energy source can be used with a geothermal heat pump<\/strong>\u00a0for heating, cooling and hot water supply \u2013 independent of seasons, weather conditions and fossil fuels.<\/p>\n<\/div><\/div><\/div>

How Does a Geothermal System Work?<\/strong><\/h2>\n<\/div><\/div><\/div>

A geothermal system consists of three core components:<\/p>\n

    \n
  1. Heat source in the ground<\/strong>\u00a0\u2013 geothermal probe, horizontal ground collector or groundwater well<\/li>\n
  2. Heat transfer fluid (brine)<\/strong>\u00a0\u2013 a water-glycol mixture that transports heat from the ground to the heat pump<\/li>\n
  3. Heat pump<\/strong> \u2013 raises the temperature level and distributes heat in the building (radiators, underfloor heating, hot water)<\/li>\n<\/ol>\n

    Principle:<\/strong>\u00a0The brine circulates through the geothermal probe in the ground, absorbs heat there and transfers it to the heat pump. The heat pump converts this into usable heating energy \u2013 similar to a refrigerator, but in reverse.<\/p>\n<\/div><\/div><\/div>

    \"Geser<\/span><\/div><\/div><\/div><\/div><\/div><\/div>
    <\/div>
    <\/div>

    Types of Geothermal Systems<\/h2>\n<\/div><\/div><\/div>

    Geothermal Probes (Vertical Collectors)<\/strong><\/h3>\n

    The most common and space-efficient method: a certified drilling company bores vertically into the ground \u2013 typically 80 to 200 metres deep, deeper where required (Geser Erdw\u00e4rme installed the world’s deepest documented PE probe at 706 m in Oftringen, Switzerland in 2007<\/strong>). A plastic probe (usually U-shaped, diameter DA32 to DA50 and larger) is inserted into the borehole and the annular space is permanently sealed with grouting material.<\/p>\n

    Advantages:<\/strong>\u00a0Minimal surface area required \u00b7 high efficiency \u00b7 stable temperatures year-round<\/p>\n<\/div>

    Horizontal Ground Collectors<\/strong><\/h3>\n

    Plastic pipes are laid horizontally at approximately 120 to 150 cm<\/strong> depth, below the frost line. For a modern single-family home, approximately 150 to 200 m\u00b2<\/strong>\u00a0of collector area is needed. The area must not be built over.<\/p>\n

    Advantages:<\/strong>\u00a0Lower installation cost \u00b7 no drilling required<\/p>\n

    Disadvantage:<\/strong>\u00a0Large surface area required \u00b7 some seasonal temperature variation<\/p>\n<\/div>

    Groundwater Systems (Open Systems)<\/strong><\/h3>\n

    Groundwater is drawn directly and fed to the heat pump via a supply well. Highly efficient \u2013 but requires extensive hydrogeological investigation and strict regulatory approval.<\/p>\n

    Advantages:<\/strong>\u00a0Highest efficiency of the three systems<\/p>\n

    Disadvantage:<\/strong>\u00a0High planning effort \u00b7 regular maintenance required<\/p>\n<\/div>

    \"GESER<\/span><\/div><\/div><\/div>
    <\/div><\/div>
    <\/div><\/div><\/div>

    Can I Use Geothermal Energy in an Existing Building?<\/h2>\n<\/div><\/div><\/div>

    Yes<\/strong>\u00a0\u2013 virtually any building can be supplied with geothermal energy today, including existing buildings. Key points to clarify when retrofitting:<\/p>\n

      \n
    • Which system (probe, collector, well) suits the property?<\/li>\n
    • Is there sufficient space for drilling equipment access?<\/li>\n
    • What is the existing heating system \u2013 can it be retained?<\/li>\n
    • Is improving building insulation worthwhile?<\/li>\n<\/ul>\n

      Important:<\/strong> Existing radiators can be connected to the heat pump \u2013 underfloor heating is not mandatory<\/strong>. What matters is that the system flow temperature is sufficiently low (ideally below 55 \u00b0C). A professional assessment is recommended.<\/p>\n<\/div><\/div><\/div><\/div><\/div>

      Geothermal Energy in Bavaria and the Allg\u00e4u Region<\/strong><\/h2>\n<\/div><\/div><\/div>

      The Allg\u00e4u and Westallg\u00e4u regions offer favourable geological conditions for geothermal installations. However, an individual site assessment is always necessary. In Bavaria:<\/p>\n

        \n
      • Permit requirement:<\/strong>\u00a0Geothermal drillings require notification and permits under Bavarian law.<\/li>\n
      • Responsible authority:<\/strong> The lower water authority (Untere Wasserbeh\u00f6rde) of the relevant district issues the water law permit \u2013 processing time usually approx. 4 weeks<\/strong>.<\/li>\n
      • Mining law permit:<\/strong>\u00a0For depths exceeding 100 m or large-scale systems, additional approval from the state mining authority is required.<\/li>\n
      • Potential maps:<\/strong>\u00a0The Bavarian State Office for the Environment (LfU) provides online geothermal potential maps for initial orientation \u2013 but these do not replace professional planning.<\/li>\n<\/ul>\n<\/div><\/div><\/div>

        Can Geothermal Energy Also Cool My Home?<\/strong><\/h2>\n<\/div><\/div><\/div>

        Yes<\/strong> \u2013 a major advantage of ground-coupled systems. In summer, the constant coolness from the ground can be used directly to passively cool the building. Since only the circulation pumps in the source and heating circuit are running, passive cooling requires only around 13% of the energy<\/strong>\u00a0used for heating \u2013 extremely economical.<\/p>\n<\/div>

        <\/div><\/div><\/div><\/div><\/div>
        \"GESER<\/span><\/div><\/div><\/div>

        What Does a Geothermal System Cost and When Does It Pay Off?<\/strong><\/h2>\n<\/div><\/div><\/div>

        Geothermal requires a higher initial investment than a gas or oil boiler. However, running costs are significantly lower, since the heat pump draws up to 75% of its energy<\/strong>\u00a0free of charge from the ground \u2013 only the drive electricity is paid for.<\/p>\n

        Typical payback period<\/strong> for a single-family home: approx.\u00a0 7 years<\/strong><\/p>\n

        Geothermal energy also receives government subsidies in Germany (BAFA Federal Funding for Efficient Buildings, KfW programmes). Consult an energy advisor for current subsidy rates.<\/p>\n<\/div><\/div><\/div>

        Is Geothermal Energy Environmentally Friendly?<\/strong><\/h2>\n<\/div><\/div><\/div>

        Geothermal heat pumps rank among the most climate-friendly heating systems available:<\/p>\n

          \n
        • Lowest CO\u2082 emissions<\/strong>\u00a0of any heating system during operation<\/li>\n
        • No fossil fuel<\/strong>\u00a0dependency \u2013 no exposure to gas or oil price volatility<\/li>\n
        • With green electricity<\/strong>, CO\u2082 output drops to virtually zero<\/li>\n
        • Contributes to the energy transition<\/strong>\u00a0and climate targets<\/li>\n
        • Geothermal probes are designed to last multiple generations<\/strong>\u00a0\u2013 no disposal issues<\/li>\n<\/ul>\n<\/div><\/div><\/div><\/div><\/div><\/div>
          <\/div>
          <\/div>

          What to Look for in a Drilling Company<\/h2>\n<\/div><\/div><\/div>

          The quality of the borehole determines the long-term success of the system. Look for:<\/p>\n

            \n
          • DVGW W 120 certification<\/strong>\u00a0(German standard for geothermal probe drillings)<\/li>\n
          • Knowledge of local geology in the Allg\u00e4u \/ Bavaria region<\/li>\n
          • Reference installations in the region<\/li>\n
          • Complete documentation of all drilling work and authority documentation<\/li>\n
          • SKZ quality mark<\/strong>\u00a0for probe materials used<\/li>\n<\/ul>\n<\/div><\/div><\/div>

            Videos \u2013 Geothermal energy simply explained<\/h2>\n<\/div>

            Our video recommendations provide a practical overview of how geothermal energy works, what to consider during installation, and how the technology can be used in existing buildings.<\/p>\n<\/div><\/div><\/div>