Geoelec workshop, Vilnius – March 22, 2012

Geothermics in Sweden

Ólafur Guðmundsson, UU Gerhard Schwarz, SGU Chris Juhlin, UU

From the Blue Lagoon, Svartsengi geothermal power plant, Iceland

Geo-Energy in Sweden

10 TWh/year - extracted from the shallow sub-surface, for

central heating, i.e., about 2 % of total energy consumption.

There is no significant geothermal electricity production.

Geoelec workshop, Vilnius – March 22, 2012

Number of wells documentet in SGU archives (2010)

Heat pump wells

Geoelec workshop, Vilnius – March 22, 2012

Lund geothermal project

1600 m3/h produced from four wells – reinjected into five wells

Aquifer is unconsolidated Cretaceous sandstone at 650 - 750 m depth

Initial T = 20 - 22 °C – current T = 17 - 18°C – reinjection T = 4 - 7°C

Currently 250 GWh/year - initially 325 GWh/year

Geoelec workshop, Vilnius – March 22, 2012

Lund geothermal project

Subsequent deep drilling to ~3.5 km yielded 130°C water, but too low permeability

Geoelec workshop, Vilnius – March 22, 2012

Temperature at 1.0 km depth in °C

Surface heat flow density (mW/m2)

Reliable heat-flow measurements are sparse

Heat flow is low

Radiogenic heat generation (A) of rocks (e.g. Rybach 1979) in μW m-3

A = d (95.2 CU + 25.6 CTh + 34.8 CK ) 10-6

d rock density in kg m-3

CU , CTh weight content of U, Th in ppm

CK weight content of K in %

Geoelec workshop, Vilnius – March 22, 2012

Geoelec workshop, Vilnius – March 22, 2012

Schwarz et al. 2010

Radiogenic heat generation of surface rocks

Are old radiogenic rocks buried under younger formations in Caledonites

Swedish Deep Drilling Program

7 potential deep drilling sites in Sweden

Pre-drilling studies have already started

VR funded drill rig for depths of 2.5-3 km

Geoelec workshop, Vilnius – March 22, 2012

Geoelec workshop, Vilnius – March 22, 2012

Existing borrholes in Sweden, with drill cores available in SGU archives Some will be used for measuring thermal properties (Schwarz et al. 2012).

Heat flow component

Continue making an inventory of shallow boreholes for temperature logging

Core sampling over the winter

Preliminary thermal modeling

May/June 2012 - locate shallow existing boreholes and check accessibility

Temperature logging of boreholes in Aug/Sep 2012

Geoelec workshop, Vilnius – March 22, 2012

Relevant expertese in Uppsala

Applied geophysics – electromagnetics and seismic imaging (UU)

Geophysical surveying (SGU)

Rock properties lab (SGU)

Seismic monitoring and microearthquake studies (UU)

Currently involved with Lawrence Berkeley Laboratories, Iceland Geosurvey and MIT in geothermal projects in Iceland and California (UU)

12-03-21 Geoelec workshop, Vilnius – March 22, 2012

Thank you

From Kerlingafjöll, central Iceland