The present phase of the integrated European geothermal project at Soultz-sous-Forets (Alsace, France), which is managed by an industrial consortium, has demonstrated that an Enhanced Geothermal System (EGS) based on three 5000 m deep wells and using improved drilling, stimulation and diagnostic methods can be used successfully to access the geothermal energy at depth. This enhanced geothermal technology can be applied over wide areas of Europe under which naturally fractured hot rock mass exists.
After a brief period of further testing, the proposed three year continuation program (i.e. 2004-2007) aims to install and operate a 1.5 MWe power plant, enabling the deep reservoir / heat exchanger created during the period 2001-2003 to be operated, evaluated and improved (if required) under realistic conditions. Both its thermal and hydraulic behaviour will be characterized over the short, medium and long term in conjunction with teams from other EGS sites; a general methodology of evaluating and developing EGS systems will be elaborated. Given positive results from the medium term tests, the power conversion unit will be increased to some 5-6 MWe at circulation rates of 80-100 l/s and a temperature of 190°C. In parallel with the hydraulic evaluation further characterization, evaluation and adaptation will be carried out on scaling and corrosion aspects, high temperature production pumps, surface heat exchangers, power conversion cycles and general reservoir management.
The pilot plant will be used to test the in-site performances of the selected equipment in order to establish preferences for technical and economical gains for future larger industrial EGS installations (25 MW el. and larger) based on a multi-well approach.
After successful operation, the pilot plant itself will be made available as a training facility to other European EGS teams.