Theistareykir Geothermal Power Plant

Landsvirkjun has just completed the construction of a geothermal plant with a 90 MW capacity at Theistareykir [Icelandic: Þeistareykir] in NE Iceland. Over a period of 10 years, Landsvirkjun invested heavily in researching geothermal in the area. Mannvit, in collaboration with Verkis, handled the design of the power stations and preparation of tender documents for up to 90 MW of electricity.

The plant has two turbine units, each with a 45 MW capacity. The first 45 MW unit was commissioned in November 2017 and the 2nd 45 MW turbine in April 2018. Mannvit and Verkís worked on the design of the power plant and preparation of tender documents. Technical assistance will also be provided during construction and testing. Mannvit prepared project design reports, designed boreholes, oversaw technical supervision of the drilling of the current boreholes and evaluated the size of the geothermal area. Mannvit also carried out project design for high voltage lines and substations, as well as evaluating the environmental impact (EIA) and performing a joint EIA of high voltage lines and power plants in the area.


Þeistareykjavirkjun 2016 -

Five exploration wells were drilled in 2002 and 2003. The first production well drilled in 2002 was promising and yielded 6 MWe. In 2016 and 2017, 10 production wells were drilled, including one in the Krafla area, making the total number of wells at the Theistareykir 18, providing enough steam for the 1st 90 MW phase. In fact, providing over 100 MW.

Landsvirkjun is owned by the Icelandic state and the country's largest electricity generator, processing 75% of all electricity used in Iceland from hydroelectric power, wind and geothermal energy. Landsvirkjun operates 17 power stations in Iceland. 


  • Project management for the consultants
  • Preparation of tender documents and procurement documents
  • Detail design, supervision assistance for mechanical installation
  • Supervision assistance for control equipment installation
  • EIA for the plant and transmission lines
  • Design of HV transmission lines
  • Design of substations
  • Well design
  • Drilling supervision
  • Reservoir modelling


90 MW 
Installed capacity in 2 phases
First exploration well
200 MW 

"There are many challenges due to the location of the plant. Theistareykir is an uninhabited area, more than 300 m higher than sea level, where there is heavy snow. Despite this, construction work could be done during the winter, thanks to the good roads that had been built. Construction of the plant’s powerhouse commenced in May 2015. The work was all on schedule, and the first unit was in operation at the end of 2017. The second unit went into operation in the spring of 2018. The entire project went as well as could possibly be expected."

Freyr Hardarson

Project Manager


Theistareykir GPP project construction (English subtitle) - video by Landsvirkjun