Geothermal heat

Geothermal energy can be used to generate energy and to heat buildings. The heat of the earth comes from the core of the earth. The way the heat is generated in the core is beyond the scope of this text. The deeper you drill into the earth's crust, the higher the temperature. The temperature at a depth of 1 meter is influenced by the average air temperature. The difference between winter and summer is only a few degrees. In the Netherlands, the temperature at a depth of 1 meter is about 10 °C. For every 10 meters deeper, the temperature rises 1 °C.

Cooling

When the temperature at 1 m below the ground is 10 °C, this layer can also be used to cool buildings. Through a tube of e.g. 100m meandering into the ground, under the crawl space of a single-family house, a house with underfloor heating can be cooled. However, the floor should not get colder than 16 °C because condensation can then occur. The only energy required for this is to pump the water around.

To heat

This tube of e.g. 100 m can also be used to extract heat. Heat pumps are currently being used. In the worst cases, these have to extract heat from the air with a temperature of -4 °C. The temperature of the ground is 10 °C and maybe a little warmer if we have used the ground for cooling. Extracting heat from this requires much less energy than extracting it from the air, despite the fact that energy is required for pumping it around.

Heat storage

Storing heat in the ground gives a better result, but that requires heat storage. It is said that there is already a municipality that has these barrels buried and that heat panels are placed on the roofs because it has been found that all homes could easily get through the winter with this. This seems to me to be a good approach because this is done collectively and certainly if the municipality is properly represented and there is also a program in which houses are brought up to the current standard in terms of insulation. In addition, there must be an arrangement that makes these adjustments feasible for all residents.
If I receive more or specific information, I will update this piece.

Other systems

There are also other ways to use geothermal energy. A description of ideas about this can be found at Energy from geothermal energy with an artificial geyser.