Direct Use

WG 8 – Direct Use of Geothermal Energy

2018 Working Group 8 Report
2017 Working Group 8 Report
2016 Working Group 8 Report


Geothermal water has been used for millennia for various applications. During the last several decades, the use of geothermal energy for a range of heating purposes has become more and more important worldwide, and the number of applications has increased dramatically. Many applications, which require heat up to a specific temperature, can use geothermal energy, such as: heating buildings, raising plants in greenhouses, drying crops, fish farming, snow melting, bathing, therapeutic purposes, and also industrial processes. In recent times, cooling by geothermal energy has become more and more important.

In 2012, four of the existing five Tasks of Working Group 8 were successfully completed. These were: Resource Characterization, Cost and Performance Database, Barrier and Opportunity Identification, and Publication and Geographical Presentation on the Web. The Task “Design Configuration and Engineering Standards” has been continued. In spring 2013, Working Group 8 was completely restructured and its members defined four new Tasks: A) New and Innovative Geothermal Direct Use Applications, B) Communication, C) Guidelines on Geothermal Energy Statistics, D) Guidelines on Statistics for Geothermal Heat Pump Applications and E) Design Configuration and Engineering Standards (continued).

The new mission of Working Group 8 is to provide unbiased active and passive information, communication and knowledge transfer to mitigate the barriers and to enhance deployment of the direct use of geothermal energy. The main objectives are to cooperate and share knowledge, and to increase the use of existing technologies, especially by boosting awareness.

Working Group 8, as part of IEA Geothermal, provides an international platform for knowledge exchange and cooperation. Working Group 8 members regularly realign their goals to meet the current needs of their geothermal direct use communities and industries. The recent Tasks and their outputs are of importance for most of the countries in the world.

The relevant industries, organizations and research laboratories of member and non-member countries interested in participating are always welcome to join the Working Group.

Publications, and presentations from the working group’s workshops, can be found at

Task A- New and Innovative Geothermal Direct Use Applications

Task Leader: Brian Carey, GNS Science, New Zealand

Geothermal direct use technologies are, in general, mature and competitive. One current focus of research and development, and industry, is the development of innovative applications to, e.g., open up new possibilities for utilization, to enhance efficiency, and to reduce costs. Also the issues of “smart cities” and “energy grids” have become more and more important. Regarding GSHPs, there is a trend towards larger systems, sometimes combined with other energy sources (e.g., solar thermal energy) and/or underground energy storage systems. In the agricultural and industrial sectors there is also a huge potential for new and innovative direct use applications. The first workshop of Task A, which is planned to be held in Fukushima, Japan, in October 2014, will concentrate on innovative applications with heat pumps, as this is of great relevance for all member countries.

Task B- Communication

Interim Task Leader: Katharina Link, Geo-Future GmbH, Switzerland

Although the worldwide technical and economic potential of geothermal direct use applications is enormous, knowledge of it by the general public and among politicians and decision-makers is relatively lacking; though the level of awareness varies widely from country to country. In some countries, like many in Europe, the potential of GSHP systems for heating residential houses is very well known, but the fact that there are many other applications is less widely known. Even in a country like New Zealand, which is characterized by an obviously huge potential, the many possibilities for geothermal direct use are generally poorly known compared to power generation. Clearly, for boosting geothermal direct use and to enhance deployment, “communication” is essential. In the first phase, activities will concentrate on collecting the available information from member countries and cooperating organizations. The exchange of experiences is fundamental for identifying barriers and opportunities, and to optimize communication activities. In 2013, the IEA Geothermal Executive Committee decided, based upon the recommendation of WG 8, to financially support a CanGEA geothermal direct use project. This project delivered a report on direct use technologies, a how-to guide on evaluating direct use opportunities, and several factsheets and workshop materials. This material, the lessons learned from the workshops recently held in Canada, and the material from other countries and organizations, will help to optimize communication in other countries.

Task D- Statistics for Geothermal Heat Pump Applications

Task Leader: Yoonho Song, Korean Institute of Geoscience and Mineral Resources (KIGAM), Republic of Korea

Different load factors among the various types of direct utilization, such as heating residential houses, office buildings, and green houses, are often not considered when estimating capacity factors. In contrast to large-scale district heating systems, it is almost impossible to monitor flow rate or thermal load for GHPs, except in applications for large office buildings. Therefore, there is significant uncertainty in the statistics for geothermal energy use with GHPs, both for national and world levels. Consequently, Task D was initiated to determine a method for estimating geothermal energy utilization with GHPs as accurately as possible.  Efforts will start by comparing methods used for computing the national statistics of several countries. Each country has its own approach for estimating thermal usage, mostly reflecting major utilization types and climate conditions. However, if the statistics for each application type and the standard load pattern of each type are made available, it might be possible to establish a recommended method, or develop a reference table for calculating the statistics. In addition, many countries do not separate the statistics for cooling with GHPs from heating with them, which causes another uncertainty in the statistics.

The main objective of Task D is to develop a suitable form of statistical table to be adopted for computing national and world statistics. The table will include all types of GHP utilization, and consider cooling as well as heating. Success will lead to comparable statistical data, and less confusion. The GHP statistical work is part of the WG 8 development of guidelines for geothermal direct use statistics.

Task E- Design Configuration and Engineering Standards

Interim Task Leader: Katharina Link, Geo-Future GmbH, Switzerland

The Scope of Task E is to collect, characterize and exchange standardized designs and practices for various applications, with the goal of minimizing the engineering related to various applications. The main concerns are quality, reliability of operation, long term efficiency and sustainability, and cost reduction through standardized procedures. Examples of successful cooperation are the dissemination of experience with quality certificate systems for ground source heat exchangers and of results from long-term monitoring of direct use installations.

Task E also includes the collection and distribution of a list of national and international standards, engineering practices and other relevant documents. This list is made available to GIA members through the WG 8 section of the IEA Geothermal website. Due to the importance of such standards, the working group members decided in 2013 to continue the Task and to regularly update the list. The current version (May 2014) contains about 40 national and 7 international documents. Most of the documents refer to near-surface systems from countries where there is already a large market. They originate mainly from Germany, Austria, Switzerland, France, and Sweden.

Participants: France, Germany, Iceland, Japan, New Zealand, Norway, Republic of Korea, Spanish Geothermal Technology Platform, Switzerland, United Kingdom, United States

Status: Ongoing

Operating Agent: GEOTHERMIE.CH, Swiss Geothermal Society, Switzerland

Working Group Leader:
Katharina Link,
Geo-Future GmbH,