Geothermal energy – sometimes named one of the most democratic sources of renewable energy, as it is present all around the globe just beneath the surface of the earth. The heat from within is partially created by the heat from the earth’s core, but mainly through the decay of radioactive materials in the ground.
Current geothermal heat pumps and systems are usually reaching a depth of around 120 meters, where the temperatures are constant and unaffected by weather conditions up above. Cold water is pumped in, warm water comes out. In the end, you have the energy for heating in houses and industrial complexes, electricity, heated water.
A research team combining scientists from different universities and research laboratories in Norway intends to go far beyond those 120 meters. They plan for 5,000 meters, 10,000 meters, and even deeper.
The reason for this is that the temperatures at those depths are much higher, hence more useful for a geothermal energy system. At 5,000 meters, one can expect 90°C (194°F). These temperatures could be used for heating up water in a cycle for energy production, direct heating, etc.
It is also possible to go even deeper, but this is where the problems start. When reaching depths of up to 10,000 meters, the heat and pressure combination becomes increasingly intense. At the very least, 370°C (698°F) will be reached, turning the rock into softer forms, crushing natural cracks and crevices. Metals, electronics, and other devices also suffer a lot or just stop working when taken to these extreme temperatures.
Although these problems make it seem difficult, the Norwegian scientists believe to have the right solution. Their advantage is the knowledge and experience collected over the years by the Norwegian oil industry. As the geology below Norway is quite a difficult one, technical progress in the past 10 years has been very great.
The oil companies are already testing methods for precise drilling and working at depths from 10,000 – 12,000 meters and the scientists hope to gain new ideas and methods for their geothermal heat pumps through these explorations. A closed-loop system has been favoured by them so far (incorporating a refrigerant being sent through a pipe into the earth, which will then come back up heated).
Although reaching such drilling depths might sound like something far in the future, they are receiving increasing interest, as they are thought to provide countries with the opportunity to be energetically independent and clean. Moreover, considering that the oil industry goes to similar depths to extract every drop of fossil fuel, it should not be a big hassle to go to the same depth to receive energy for free. Hopefully, it will only be a matter of time until we all receive our energy from some renewable source, possibly geothermal heating.