Geothermal energy is the heat coming out of core of Earth. This heat can be used to produce electricity and heat energy with the help of geothermal power stations. It is related to renewable energy sources. In the volcanic regions circulating water is heated more than boiling point at low depth and it sometimes comes to surface which is known as geysers. Access to underground hot water is achievable with the help of deep boring. It is also possible to get hot dry rock, which are extended within the earth. The hot water can be got from them as well.
The earth is hotter in the center. Scientists suppose that the temperature of the Earth core is about 4000-5000 degrees Celsius. So, all the rocks should exist in liquid condition near the core.
As you may know from school program, the Earth was formed about four billion years ago as one of the results of so-called Big Bang.This theory says that everything is formed from cosmic gases and our Earth too. It was very hot at the very beginning, but became cooler with time which was one of the reasons for appearing life on our planet. And now it remains hot inside giving a part of its heat energy to us.
Due to the power of Earth’s heat we could cover today’s global energy demand at 30 million years. Consequently, accumulated reserves of energy in the Earth on the scale of humanity are as inexhaustible as solar energy reserves.
In Central Europe, the temperature in the upper layers of earth rises at 3 degrees Celsius with every 100 meters of depth. In the upper mantle the temperature of 1200 degrees Celsius dominates. It is probably up to 6000 degree Celsius in the Earth core. The temperature of earth surface is mostly determined by the sun. But as the soil is a poor conductor of heat at the depth of 15-20 meters below the effects of sun is no longer determined.
Comparing with other renewable energy sources geothermal energy has one significant advantage: it is always available regardless of daytime, year or the prevailing climatic conditions. There is no need to create costly transport system as geothermal energy can be got on the spot. It has no direct emissions of carbon dioxide, because of avoiding the traditional process of combustion. Minor emissions of carbon dioxide are produced only by the application of electric units.
Meanwhile, we possess the technology that enables us to use available resources almost universally. In Germany, it is produces clean heat based on geothermal energy with the capacity of 600 megawatts (using the near-surface geothermal energy from heat pumps). Determined capacity worldwide is from 15000 to 20000 MW (thermal energy) and 8400 MW (electricity). And this is only a small part of what we can get. Heat flow from the depths is sufficient to cover all our heat consumption demands.
The USA is one of the leading countries in geothermal energy usage. The share of geothermal energy is only 1 percent from the entire electricity production in this country. But with the development of modern technologies geothermal energy can be used to produce one third of the entire energy for the country. Geothermal energy is considered to be one of the most reliable types of renewable energy. Heat generated by the earth is available day and night in any weather. The United States of America extract and use more geothermal energy than any other country and in the next 10 years the use of this energy source could be doubled or even tripled.
Geothermal energy is accessible to many people in many places in the world. Nowadays it is also used for heating homes and other buildings. This is possible due to the usage of heat pumps. This technology is based on the use of surface geothermal energy (not deeper than 100 meters) and is more convenient and perfect than the use of air-conditioners.
As you can see geothermal energy is one more source of alternative energy, which is widely used nowadays. This branch of renewable energy is supposed to be promising and developed in future, as many countries and organizations make investments in it.