A systematic review of enhanced (or engineered) geothermal systems: past, present and future

Abstract

Enhanced (or engineered) geothermal systems (EGS) have evolved from the hot dry rock concept, implemented for the first time at Fenton Hill in 1977. This paper systematically reviews all of the EGS projects worldwide, based on the information available in the public domain. The projects are classified by country, reservoir type, depth, reservoir temperature, stimulation methods, associated seismicity, plant capacity and current status. Thirty five years on from the first EGS implementation, the geothermal community can benefit from the lessons learnt and take a more objective approach to the pros and cons of 'conventional' EGS systems.

Geological and drilling aspects of construction and exploitation geothermal systems HDR/EGS

“…These are: Ogachi in Japan, Falkenberg in Germany, Fjällbacka in Sweden, Bad Urach in Germany and Basel in Switzerland [1]. …”

“…In the next years were performed further stimulation treatment [28]. Some authors [1,8] give the example of a project Hijiori as geothermal system is still running. Table 2 Hydraulic parameters of the longest circulations in selected systems HDR/EGS [8] * Injection well given first ** Production wells delimited by "/"…”

“…To data recording has been developed combined measurements with electrical tools and fiber-optic distributed temperature sensing (DTS). The data transfer to surface is problematic and can only be done a discontinuous manner [1,7].…”

“…By means of injection pump (2), water from the tank (3) is introduced by injection well (4) to the reservoir, which is situated in at a depth of 3 to 10 km with low permeability rocks (8). Next the heated fluid by the production well (5) flows to the power plant (1). Wells are connected artificially by fracturing zone (6), resulting from treatments aimed at increasing the permeability of the rock mass [28].…”

Overview of Geothermal Energy Projects in Europe and the GEISER Project on Induced Seismicity

“…For almost 100 years geothermal energy has been used for electricity generation. Today, so called Enhanced Geothermal Systems (EGS), enable the exploitation of the Earth's heat for producing electricity even if the natural productivity from water resources is not sufficient (Breede et al 2013). To extract energy from hot, poorly permeable rock, water is injected from the surface into boreholes with high pressure in order to create fractures and open them in the hot rock.…”