Review on the International Legal Status for the Thermal Use of Groundwater

Abstract

Worldwide the number of shallow geothermal installations (< 400 m depth) is continuously rising. One consequence is widespread man-made temperature anomalies in natural aquifers. These have to be controlled to guarantee long-term usability of the geothermal reservoirs and to avoid adverse effects on groundwater ecosystems. However, nationally as well as internationally, regulations to achieve these controls are very heterogeneous, sometimes contradictory and scientifically questionable. For example, what is the optimal distance between adjacent, potentially competing ground source heat pump or groundwater heat pump systems? Answers to derive a good code of practice have to balance technical, economic and ecological criteria. As an overview of the current situation, we started an international survey that compares various regulations regarding minimum distances and temperature limits for the use of shallow geothermal installations (open and closed systems). We discuss the typical criteria applied and present some preliminary findings.