Deep geothermal energy for heating and cooling

Abstract Geothermal energy is a clean and renewable energy source deriving from the exploitation of the heat flux reaching the surface from the deeper part of the Earth's crust. The heat can be utilized in agriculture (horticulture, drying, fish-breeding, etc.), industrial processes, balneology, heating (and cooling) districts, and individual buildings, including both small and large schemes. The cost structure of a geothermal project is dominated by three major items: exploration, drilling, and facility construction. The direct heat utilization worldwide is reported in 78 countries. The last available data on thermal energy used are 438,071 TJ/year (121,696 GWh/year). The energy savings is impressive, about 46.2 million tons of oil equivalent annually, preventing 46.6 million tons of carbon and 148.2 million tons of CO 2 being released to the atmosphere. Geothermal energy is becoming increasingly more competitive with fossil fuels, and its environmental benefits should accelerate in the future.