| Abstract |
Geothermal or ground source heat pump (GSHP) applications became dominant in direct use of geothermal heat covering more than 55% of worldwide heat uses in 2015. The major application of GSHP is still for heating individual residential houses, especially in northern Europe. The number of large installations for office buildings and apartments is recently increasing in Europe and North-East Asia. GSHP installations at public and commercial buildings are not only used for heating but also for cooling, and energy utilization in cooling mode is getting more and more important. Although the contribution of GSHP to global thermal energy uses is getting bigger, official statistics (for example, International Energy Agency; IEA) of worldwide energy uses do not consider this type as independent renewable energy sources despite the fact that IEA classifies heat pumps (from air, ground, water, and waste sources) as a renewable energy source. The International Geothermal Association (IGA) collects data for GSHP installations through the World Geothermal Congress (WGC) every five years. However, in their geothermal utilization statistics WGC only accounts for the heating mode of GSHP, because cooling with GSHP does not extract but stores heat in the ground. However, cooling with GSHP is getting more important and has a huge potential worldwide. As no other statistics consider this important energy utilization, IEA Geothermal has devised a new statistical scheme as a result of Working Group activities. Data for the new statistical scheme is collected through an Excel spreadsheet with input options for installations like individual residential houses, commercial/institutional/multi-family buildings and others such as greenhouses, separately. By adopting a concept of gross and net energy production with input of equivalent full load hours and seasonal performance factors which are different not only for each installation type but also depending on heating or cooling, annual thermal energy use and renewable energy production are automatically calculated for heating and cooling application, separately. The information sources and the accuracy of the information can also be added, allowing to evaluate the reliability of the statistics. Additionally, the new statistical questionnaire of IEA Geothermal includes a separated sheet for ‘free cooling’, if available. This questionnaire comes with a user guide for better understanding of the underlying principle. IEA Geothermal started collecting the new geothermal statistical information from the participating countries in 2018 with this new scheme. Overall, this new statistical questionnaire bridges the gap between the official energy statistics and the industry association statistics, and at the same time specifies the individual query values and includes the increasingly important cooling application. IEA Geothermal suggests that it is considered as a reference for revising the data collection format of WGC in future. Reliable and comparable geothermal energy statistics are an important pillar in communication activities towards politicians, decision makers and the general public. |