In the broad sense, geothermal resources are understood as the reserves of deep heat of the Earth. They can be presented in the form of steam, hot water, brine of natural origin or formed as a result of the artificial introduction of gas, water and other liquids into geothermal formations. Distinguish also low and high potential geothermal resources. The resource potential of geothermal energy is recognized as inexhaustible as solar or thermonuclear.
The share of geothermal resources in the fuel and energy balance of industrialized countries is on average 5–10%. The United States of America occupies the first place by a wide margin, but countries such as the Philippines and Japan are already very close. In Iceland, 80% of the population heat their homes with geothermal heat. Currently, up to 60% of the geothermal resources used are used in balneology.
The identified reserves of geothermal water with a temperature of 40–200 ° С, mineralization up to 35 g / l and a depth of up to 3500 m in Russia can provide about 14 million m 3 of hot water per day, which is equivalent to about 30 million tons in the amount of energy transferred fuel equivalent (fuel equivalent). For the needs of heat supply in the regime of 70/20 ° C (in the numerator, the incoming temperature, and in the denominator – the discharged coolant), they are spread over 95% of the country and amount to 57 trillion tons. t., including in heating mode (90/40 ° С) – 69% of the territory and 30 trillion t. t
Currently, the country operates geothermal water deposits on Sakhalin Island, the Kamchatka Peninsula and the Kuril Islands, in the Krasnodar and Stavropol Territories, in the republics of Dagestan, Ingushetia. The world’s first geothermal power station (GeoES) – Pauzhetskaya – was built in the Soviet Union in 1965 in the south of the Kamchatka Peninsula. It still works and its capacity reaches 11 MW. After a significant break, when other countries went far ahead in the construction of geothermal power plants, in 1999 a new Mutnovskaya geothermal station with a capacity of 12 megawatts was commissioned.
Unlike other regions of the country, the Kamchatka Peninsula and the Kuril Islands lie in the zone of modern volcanism, where thermal waters in limited areas and shallow depths have temperatures of 80-200 ° C and higher – on the Kamchatka Peninsula there is the famous Valley of Geysers with natural fountains of hot water and a couple.
When compiling a map of geothermal heat supply resources, geothermal energy resources of the entire territory of Russia were estimated for heat supply needs up to a depth of 10 km. The assessment was made for the circulation technology for the development of petrogeothermal resources in temperature conditions – 70/20 ° С and 90/40 ° С.