Our soils can provide sustainable energy. Aquifer Thermal Energy Storage (ATES) is a smart way to re-use heat and cold in buildings and it is widely recognized as promising technology for sustainable energy. Global demand for heating and cooling in the built environment accounts for about 40% of total primary energy consumption. ATES is a simple way of meeting that demand by using the soil. The Climate-KIC project ‘Europe-wide Use of Sustainable Energy from aquifers’ – E-USE(aq) – demonstrated how ATES systems can be implemented in several countries. It included six pilot projects in five countries that will generate a flywheel effect for the introduction of ATES systems throughout Europe.