Our underground is full of carbon free energy we are currently using barely. Anyway some cultures like the Bulgarian are quite connected to this source of energy through their balneology.
Geothermal heat most of us know from thermal spas which last from ancient roman times and the 19th to 20th century when they primaly functioned as social meeting points, pools of exchange and medical retreatment sites for aristocrats and usual citizen as well. Today countries like Japan, Island, Hungary, the Czech Republic, Austria, Italy, Turkey and especially Bulgaria are keeping this baneological tradition.
The available thermal energy comes from the magma and water flows moving earthplates like the Eurasian-/ and African Plate under pressure and radioactive decay below our surface. So if the extrem hot center of the earth is 6371 km far away depending of our position on the geoid we can count with an avarige accellerating temperature of 3°C/100 m drilling in the earth in the upper part of our surface.That is the reason why enegeniers use the hot water from taped aquiferes for heating buildings and use hot steams to generate electricity through turbines.(Graph: CC Geothermal Gradient Wikimedia, 0 Kelvin = -273.15 °C, deepest borehole on earth 12 km Kola, Russia)
The big advantage of this renewable power is, that you can use it anywhere on the planet despite of the actual weather conditions. If the drilling can be the same expensive like drilling for oil up to 2000 – 3000 m the heat flow of thermal water never stops because it is possible to reuse the water in a cycle. In terms of sustainability it is absolutely important to use this source of energy especially in advantageous regions where tektonic plates convergate, divergate or move in faults. In some of these contact areas melted continental crust goes up with a phenomenon of volcanoes, subvolcanoes or fumaroles. Also inbetween the plates mantle plumes exist an offer heat flows not as deep as in geological less active zones what makes drilling cheeper.
In Bulgaria most of the hotwater boiled above the Mohorovičić discontinuity (zone of geological desity anomaly) comes out of the earth without any drilling because of the location of the country next to the boundaries of the Anatolian-/, Moesian-/ and Westeuropeanplate and excellent geologic conditions with a lot of cracks in the usually massive groundmass like granite or limestone.
Advantages and Disadvantages of using Geothermal Energy in Electric Generators
| Advantage | Disatvantage |
| limitless source of energy | higher risks for earthquakes in borehole regions |
| 24 h available | ions kristalize in pipes, lot of replacement and cleaning acts |
| using the restheat after kondensation of hotsteams for heating buildings | big costs to drill (high temperatures and pressure in the ground can distroy the drill easily) |
| using the inons in the mineralwater to gain lithium and katalize hydrogen reaction parallely | existence of low miniralizing levels |
| water can be reused in a geothermal cycle | in areas without thermal aquifaeres, fracking danger can cause earthquakes |
| can be installed anywhere | more complicated to install then windturbines or solarpanels |
| possibility of parallel banelogic use | low efficiency |
| nearly no waste after using the natural media of water | carbondioxide waste during the construction |
| possibility of cheep and fast “acid drilling” through limestone or sandstone groundmass and benefit from natural or anthropgen cracks in the rocks. (Caves, underground tunnels, closed cole mines, salt mines, metal mines etc.) | danger of tektonik activities near borholes, they can be closed during low earthquaces mag. > 5,5 (Richterskala max. 10) easily or run out dry |