| Keywords |
direct-use, spas, balneology, space heating district heating, aquaculture, greenhouses, ground-source heat pumps, industrial application, snow melting, energy savings, wells, drilled, manpower, investment |
| Abstract |
This paper presents a review of the worldwide applications of geothermal energy for direct utilization and updates the previous survey carried out in 2015. We also compare data from WGC1995, WGC2000, WGC2005, WGC2010, and WGC2015 presented at World Geothermal Congresses in Italy, Japan, Turkey, Indonesia and Australia. As in previous reports, an effort is made to quantify geothermal (ground-source) heat pump data. The present report is based on country update papers received from 62 countries and regions reporting on their direct utilization of geothermal energy. Twenty six additional countries were added to the list based on other sources of information. Thus, direct utilization of geothermal energy in a total of 88 countries is an increase from 82 in 2015, 78 reported in 2010, 72 reported in 2005, 58 reported in 2000, and 28 reported in 1995. An estimation of the installed thermal power for direct utilization at the end of 2019 is used in this paper and equals 107,344 MWt, a 51.4% increase over the 2015 data growing at a compound rate of 8.65% annually. The thermal energy used is 1,014,006 TJ/year (281,668 GWh/yr.), a 71.1% increase over 2015, growing at a compound rate of 11.3% annually. The distribution of thermal energy used by category is approximately 59.2% for geothermal (ground-source) heat pumps, 18.0% for bathing and swimming (including balneology), 15.6% for space heating (of which 91.0% is for district heating), 3.5% for greenhouse heating, 1.6% for industrial applications, 1.3% for aquaculture pond and raceway heating, 0.4% for agricultural drying, 0.2% for snow melting and cooling, and 0.2% for other applications. Energy savings amounts to 602 million barrels (90.4 million tonnes) of equivalent oil annually, preventing 78.9 million tonnes of carbon and 255.1 million tonnes of CO2 from being released to the atmosphere. This includes savings for geothermal heat pumps in the cooling mode (compared to using fuel oil to generate electricity). Since it is almost impossible to separate direct-use from electric power generation for the following, they are combined: approximately 2,647 wells were drilled in 42 countries, 34,500 person-years of effort were allocated in 59 countries, and US $22.262 billion invested in projects by 53 countries. |