| Title | 50 Years of Utilization in the Low-Temperature Geothermal Reykir Areas, SW-Iceland |
|---|---|
| Authors | Auður Agla Óladóttir, Finnbogi Óskarsson, Sigurður G. Kristinsson, Þráinn Friðriksson |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | This paper explores the development of low-temperature geothermal utilization in the Reykjahlíð and Suður-Reykir areas—collectively called the Reykir areas—in southwest Iceland. Drilling began ~80 years ago, and the fields have played a key role in district heating for the capital region ever since. These geothermal systems are connected to an extinct high-temperature system, originally formed by volcanic activity around two million years ago and later influenced by the Krýsuvík volcanic system. Though Suður-Reykir and Reykjahlíð have been managed as separate systems in daily operations and in historical context, emerging evidence indicates that they may form a single interconnected geothermal system. This finding highlights the need for a comprehensive reanalysis of existing geochemical data and the collection of new data, including isotope analyses, to improve understanding of fluid dynamics, system evolution, and to develop a conceptual model. The Reykir fields are highly productive by Icelandic low-temperature standards. Over the past 50 years, more than 800 L/s of 80–90°C water have been extracted on average, with no signs of depletion. Isotope data suggest long residence times for geothermal fluids, though sustained extraction may influence apparent water age. Significant drilling of new production wells is planned in the coming years. Although current monitoring shows no signs of reaching system limits, it will be crucial to closely monitor water levels, temperatures, and chemical compositions. Chemical sampling and hydrological monitoring are essential to ensure sustainable use and improved understanding of this complex geothermal resource. |