Scientific achievements and regulation of shallow geothermal systems in six European countries - A review

A legislative framework is suggested on a European Union level that gives a unified definition of shallow geothermal systems, preferably on enthalpy basis, and lays down the principles of permitting process and criteria for sustainable GHP systems based on scientific results tolerating differences due to local geological and hydrogeological properties. A clear distinction of low-risk systems is desirable to aid the simplification of administrative procedure.