ES-Géothermie (ESG) is a subsidiary of the ES (Electricité de Strasbourg) Group, part of EDF and is located in Alsace. ESG is a center of expertise for deep geothermal energy Enhanced Geothermal System (EGS). This engineering company is made of scientists, engineers and technicians. ES, the mother company of ESG owns many geothermal leases in Alsace aiming to develop both geothermal electricity and heat. ESG team has been involved in different steps of EGS development from concept, exploration, drilling activity, reservoir study, power plant construction, and exploitation. ESG is currently responsible for the exploitation and maintenance of both the Soultz-sous-Forêts and Rittershoffen geothermal plants.