The article provides a summary of a report, “Direct Utilization of Geothermal Energy 2020 Worldwide Review”, which was prepared by John W. Lund (firstname.lastname@example.org) and Aniko N. Toth (email@example.com). The report is based on country update papers received from 62 countries and regions reporting on their direct utilization of geothermal energy at the World Geothermal Congress 2020 (WGC2020). Twenty-six additional countries were added by the authors to the list based on other sources of information to arrive at the trends.
Direct utilization of geothermal energy is one of the oldest, most versatile and most common forms of utilizing geothermal energy. It has been growing gradually with more and more countries finding applications for both direct and indirect use.
The total worldwide installed capacity for geothermal direct utilization worldwide is estimated to be 107,727 MWt by end-2019, a 52 per cent increase over the capacity reported at the World Geothermal Congress 2015 (WGC2015). This implies an annual compound rate of growth of 8.7 per cent. As of 2019, the total annual energy use is reported to be 1,020,887 TJ (283,580 GWh), indicating a 72.3 per cent increase over WGC2015 and a compound annual growth rate of 11.5 per cent. The worldwide capacity factor is 0.300 (equivalent to 2,628 full load operating hours per year), an increase from 0.265 in 2015 and 0.28 in 2010, but a decrease compared to 0.31 in 2005 and 0.40 in 2000. The recent higher capacity factor and growth rate for annual energy use is due to the increase in geothermal heat pump installations even though they have a low capacity factor of 0.245 worldwide.
The growing awareness and popularity of geothermal (ground-source) heat pumps have had the most significant impact on the direct-use of geothermal energy reported in 2019. The annual installed capacity grew 1.54 times at a compound rate of 9.06 per cent. The annual energy use of these units grew 1.84 times at a compound rate of 12.92 per cent compared to that reported during WGC2015. This is due, in part, to better reporting and the ability of geothermal heat pumps to utilize groundwater or ground-coupled temperatures anywhere in the world. The five leading countries for geothermal heat pumps in terms of installed capacity (MWt) are China, USA, Sweden, Germany, Finland, and in terms of annual energy use (TJ/yr) are China, USA, Sweden, Germany and Finland. An estimated 6.46 million units are installed worldwide, with also the leaders accounting for 77.4 per cent of these units.
|Region/Continent||No. of Countries||MWt||TJ/year||GWh/year||Capacity Factor|
|Central America and Caribbean||5||9||195||54||0.687|
|Commonwealth of Independent States||5||2,121||15,907||4,419||0.238|
|Central and Eastern Europe||17||3,439||28,098||7,805||0.259|
|Western and Northen Europe||17||28,947||236,745||65,762||0.259|
The five countries with the largest direct-use (with geothermal heat pumps) installed capacity (MWt) are China, USA, Sweden, Germany and Turkey, accounting for 71.1 per cent of the world capacity and five countries with largest annual energy use with geothermal heat pumps (TJ/yr) are China, USA, Sweden, Turkey and Japan, accounting for 73.4 per cent of the world use. However, an examination of the data in terms of land area or population shows that the smaller countries dominate, especially the Nordic ones. The top five for installed capacity (MWt/population) then become Iceland, Sweden, Finland, Switzerland and Norway; and for annual energy use (TJ/yr/population) are Iceland, Sweden, Finland, Norway and New Zealand. The top five in terms of land area for installed capacity (MWt/area) are Switzerland, Netherlands, Iceland, Sweden and Austria; and in terms of annual energy use (TJ/yr/area) the leaders are Switzerland, Iceland, Sweden, Hungary and Austria. The largest percentage increase in geothermal installed capacity (MWt) over the past five years was in Iceland, Hungary, France, Egypt and Australia; and in terms of annual energy use (TJ/yr) over the past five years was in Spain, Yemen, Australia, Kenya and Georgia. Most of these increases were due to geothermal heat pumps installations or better reporting on bathing and swimming use. In 1985, only 11 countries reported an installed capacity of more than 100 MWt. By 1990, this number had increased to 14 by 1995, to 15 by 2000, to 23 by 2005, to 33 by 2010, to 36 by 2015, and 38 by 2020.
The five countries with the largest direct-use, without geothermal heat pumps, in installed capacity (MWt) are China, Turkey, Japan, Iceland and Hungary, accounting for 76 per cent of the world capacity. The five countries with the largest annual energy use (TJ/yr), without geothermal heat pumps, are China, Turkey, Japan, Iceland and New Zealand, accounting for 76.5 per cent of the world use.
|United States||20,713||United States||152,810|
|United States||20,230||United States||145,460|
Application of geothermal energy
Geothermal energy can be put to use across a number of applications. Based on the data submitted by various countries at the WGC2020, it has been estimated that district heating represents 91 per cent of the installed capacity and 59 per cent of the annual energy use. Snow melting represents the majority (over 90 per cent) of the snow melting/air conditioning category. “Other” is a category that covers a variety of uses, details of which are not frequently provided, but is known to include animal husbandry, cultivation of spirulina, and carbonation of soft drinks.
Geothermal heat pumps: Geothermal (ground-source) heat pumps have the largest geothermal use worldwide, accounting for 71.6 per cent of the installed capacity and 59.2 per cent of the annual energy use. The installed capacity of 77,547 MWt and the energy use is 599,981 TJ/yr, with a capacity factor of 0.245 in the heating mode. Although most of the installations occur in North America, Europe and China, the number of countries with installations increased from 26 in 2000, to 33 in 2005, to 43 in 2010, to 48 in 2015 and to 54 in 2020. The equivalent number of installed 12 kW units (typical of USA and Western European homes) is approximately 6.46 million. This is a 54 per cent increase over the number of installed units reported in 2015, and over twice the number of units reported in 2010. The size of individual units, however, ranges from 5.5 kW for residential use to large units over 150 kW for commercial and institutional installations.
Space heating: Space heating, including individual space heating and district heating, has increased 68 per cent in installed capacity and 83.8 per cent in annual energy use over WGC2015. The installed capacity now totals 12,768 MWt and the annual energy use is 162,979 TJ/yr. In comparison 91 per cent of the installed capacity and 91 per cent of the annual energy use is in district heating (29 countries).
Greenhouses and covered ground heating: Worldwide use of geothermal energy for greenhouse and covered ground heating increased by 24 per cent in installed capacity and 23 per cent in annual energy use. The installed capacity is 2,459 MWt and 35,826 TJ/yr in energy use.
Aquaculture pond and raceway heating: Aquaculture use of geothermal has increased over WGC2015, amounting to a 36.5 per cent increase in installed capacity and 13.5 per cent increase in annual energy use. The installed capacity is 950 MWt and the energy use 13,573 TJ/yr.
Industrial process heat: This is a category with applications in 14 countries, one less than in 2015. These operations tend to be large and have high energy consumption, often operating year-round. Examples include: concrete curing (Guatemala and Slovenia), bottling of water and carbonated drinks (Bulgaria, Serbia and the United States), milk pasteurization (Romania and New Zealand), leather industry (Serbia and Slovenia), chemical extraction (Bulgaria, Poland and Russia), CO2 extraction (Iceland and Turkey), pulp and paper processing (New Zealand), iodine and salt extraction (Vietnam), and borate and boric acid production (Italy). The installed capacity is 852 MWt and the energy use is 16,390 TJ/yr, an increase of 38.8 per cent and 56.8 per cent respectively, compared to WGC2015.
Approximately $22.262 billion were reported as invested in geothermal energy by 53 countries during the period 2015-2019 for both electric power (64 per cent) and direct-use (36 per cent), about 11.1 per cent more than the 2010-2014 amount for 49 countries. The average was $420 million per country, with countries investing over $500 million being Indonesia, Turkey, China, Taiwan, Kenya, Republic of Korea, Mexico, Chile and Italy (in descending order). In terms of categories of investment, 27.9 per cent was for electric power utilization in 16 countries, 15.4 per cent was for direct-use in 30 countries, 32.4 per cent was for field development including production drilling and surface equipment in 33 countries, and 24.3 per cent for R&D including surface exploration and exploratory drilling in 47 countries for a total of $22.262 billion.
|Continent||No. of countries||Investment ($ billion)||Share in total investment (%)|
As earlier, several countries stand out as major producers and consumers of geothermal fluids for direct use (China, USA, Sweden, Turkey, Japan, Germany, Iceland, Finland, France, and Canada); however, in most countries, development has been slow. This is not surprising as fossil fuels are a major competitor. Another obstacle is the initial high investment costs of geothermal projects. However, many countries have been doing the necessary groundwork, conducting inventories and quantifying their resources in preparation for renewed development once the economic situation improves, and once governments and private investors can see the benefits of developing a domestic renewable energy source. This is true for many of the east African countries, such as Djibouti, Eritrea, Malawi, Mozambique, Rwanda, Tanzania, Uganda, Zambia and Zimbabwe, which have potential geothermal resources associated with the African Rift Valley. The distribution of geothermal use by continent indicates that Asia and Europe are the leaders, with 57 of the 88 countries reporting, for 77 per cent of the world’s installed capacity (MWt) and 80.6 per cent of the direct-uses (TJ/year).
With the increased interest in geothermal (ground-source) heat pumps, it is now evident that geothermal energy can be developed anywhere for both heating and cooling. They now make up 72 per cent of the installed capacity (MWt) and 58.8 per cent of the annual energy use (TJ/yr). This use has increased since 2015. Low-to-moderate temperature geothermal resources are also being used in combined heat and power plants (CHP), where hot water, often with temperatures below 100oC, is first run through a binary (organic Rankine cycle) power plant, then cascaded for space heating, swimming pools, greenhouses, industrial applications, and/or aquaculture pond heating, before being injected back into the aquifer. CHP projects certainly maximize resource use while improving ROI. This has been shown in Iceland, Austria, and Germany, as well as on the Oregon Institute of Technology campus in Klamath Falls, Oregon, USA.