The future of geothermal development in IcelandA presentation by Ólafur G. Flóvenz at GGW conference in Reykjavík, 24.11.2016

Primary energy consumption in Iceland 1940-2015

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1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

PJ

Hydro

Geothermal

Oil

Coal

Peat

Slide from Árni Ragnarsson, ÍSOR

UGS – Unconventional Geothermal Systems

− To develop and use EGS technology at present reservoir depths − To address Superhot Geothermal Systems− To explore for high temperature systems inside the volcanic zone of Iceland but

outside the presently known high temperature system.

Simplified geothermal map of Iceland

© Ólafur G. Flóvenz

The volcanic rift zone about 32000km2 and with average temperature gradient of about 100 °C/km

Protected High temperature fieldHarnessed high temperature field

Sketch of a typical magmatic geothermal system

Downflow cooling

Low permeability rock

Heat source

Permeable fractures

250-350°C reservoir

Steam zone

High permeability zone, superheated or supercritical fluid

Resistivity structure and natural seismicity

Outside the known H.T. fields

Superhot well into the magmatic intrusion

An EGS wellConventional well

Example of Superhot Geothermal Systems: IDDP-1 in Krafla

Figure from G.Ó. Friðleifsson af HS OrkaPhoto: Elvar Eiríksson, ÍSOR

Some lessons from IDDP-1

− The exploration method used to site the well did not have enough resolution to detect the magma body at 2 km depth

− The well design, selection of casing material and cementing methods need to be improved to avoid short lifetime of the well and its wellhead units.

− Chemical problems related to harsh chemistry of the steam has to be solved.

− At the top of the magma thin but highly permeable zone exists, most likely due to effective heat extraction and subsequent cooling of the rock.

− This observation fits perfectly with the experiment from extracting heat from the molten lava on the Vestmann Islands in the 1970ees.

400°C100°C0 m

60 m

From the ÍSOR database

IDDP-2

Photo: Tobias B. Weisenberger, ÍSOR Figure from Egill Árni Guðnason, ÍSOR

Induced seismicity around IDDP-2

Beautiful landscape to be protected

Photo from Ragna Karlsdóttir, ÍSOR

Geological maps

International co-operation

Geothermal plant in Indonesia Hot springs in New_Zealand

Photo: Ólafur G. Flóvenz

Urgent future R&D topics:

− Development of exploration methods to estimate distribution of temperature and permeable fractures in the deeper part of geothermal reservoir in volcanic environment.

− Development of methods to estimate the mechanical properties of rock in superhot geothermal systems.

− Find the best methods to exploit and to stimulate superhot geothermal systems.− R&D to introduce and test new concepts in design of boreholes that sustain

superhot geothermal fluids. This includes studies of casing material and wellhead units, improved cementing methods, flexible casing couplings etc.

− R&D to solve chemical problems related to use of superhot fluid with harsh chemistry.

Thank you