The drilling rig Jötunn drills an exploratory borehole at Theistareykir in the summer of 2007.
The geothermal area at Þheistareykir is considered to be one of the three largest geothermal areas in north-east Iceland. Þheistareykir ehf. was established in April 1999. The establishing parties are the power companies Orkuveita Húsavíkur and Hita- og Vatnsveita Akureyrar (now Norðurorka) together with with the districts Aðaldælahreppur and Reykdælahreppur. In the autumn of 2005, Landsvirkjun acquired a 32% shareholding in the company.
Theistareykir ehf. intends to construct an up-to-150 MW geothermal power station at Þheistareykir in the district Aðaldælahreppur in the county of Þingeyjarsýsla. The construction is subject to assessment pursuant to the Environmental Impact Assessment Act No. 106/2000.