International Legislation of Shallow Geothermal Energy Use

Climate change, energy savings and energy autonomy are frequently discussed topics. Hence, renewable energy resources are currently promoted worldwide. One of these is geothermal energy. Worldwide the number of shallow geothermal installations (< 400 m depth) is continuously rising. One consequence is widespread man-made temperature anomalies in natural aquifer systems. 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 (GSHP) or groundwater heat pump (GWHP) systems? Answers to derive a good code of practice have to balance technical, economic and ecological criteria. The objective of our study is to review the current international legal status of thermal use of groundwater. We present the results of an international survey, which offers comprehensive insight in the worldwide legal situation of closed and open systems of shallow geothermal installations. The focus is on minimum distances of these systems and limits for groundwater temperature changes. We can conclude that there are only few regulations and recommendations for minimum distances of these installations and groundwater temperature changes. Some countries have no regulations and in addition if recommendations are given, these are not legally binding. However, to promote shallow geothermal energy as an economically attractive and sustainable energy source, an international homogeneous legislation is necessary.