The Þeistareykir Geothermal Power Station

Landsvirkjun has conducted years of research on the development of a geothermal power station at Þeistareykir. Construction began on the project in 2015 and the 90 MW Þeistareykir geothermal project is being executed in two 45 MW phases.

The first turbine is expected to come online in the end of 2017 and the second unit in April, 2018.

Information on Þeistareykir in the 2016 Annual report

See more information on Þeistareykir in leaflet






Production process

An abundance of thermal energy is continuously emitted by the Earth’s core. The water cycle transports thermal energy from deep in the Earth’s crust and up to the surface

Energy extraction requires drilling to lengths of approximately 2km into the earth. The geothermal fluid extracted from these wells is a mixture of boiling water and steam and also contains gases and dissolved minerals.

The steam separator separates the steam from the water and the steam is then utilised for energy production. The steam is then transported to the turbine unit which consists of a generator and turbine. The steam drives the blades in the turbine which rotate the generator, thus creating electricity. The condenser cools the steam from the turbine, creating condensate and cooling towers spray the hot condensate from the condenser onto cooling racks where the air cools it. Separated water is re-injected back into the geothermal reservoir where the water cycle continues.

Þeistareykir Geothermal Power Station

Project status

Preparation for the development of Þeistareykir began in 1999 when the first exploratory wells were drilled. Preparation work for construction has been underway since 2011. Extensive preparation measures were undertaken in 2014 with a view to beginning work at Þeistareykir, at short notice.

Construction work was completed on the first 15 km of the Þeistareykir access road, on the north side from Húsavík, including road surfacing. An electrical distribution system and telecommunications were set up in the area. Groundwork on the powerhouse site was completed and water utilities were constructed as well as landscaping work.

Drilling work was completed for the re-injection wells, cold water supply, run-off water wells and exploratory wells, for groundwater monitoring purposes, at the power station. Work camps have also been set up for on-site for Landsvirkjun employees including a cafeteria, sleeping quarters for 28 people and an office block. Work camps have also been set up for on-site contractors.

All applications for the main utilisation licenses and development permits have been completed. All the permits/licenses for a 90 MW power station have been approved and an Environmental Impact Assessment for a 200 MW power station has been completed, with positive feedback from the Icelandic National Planning Agency.

Main project components

Preparation measures have been underway in the area in recent years including the construction of an access road from Húsavík, groundwork on the powerhouse site, the construction of water utilities and the development of the necessary infrastructure within the area.

Drilling was completed in 2014 on re-injection wells and wells for run-off water as well as exploratory wells to support further research on groundwater.

Construction work on the powerhouse began in 2015 as well as the steam supply system. The powerhouse unit includes a facilities building and workshop, as well as two turbine halls. A steam separator station, re-injection system and pumping station for the cold water supply is also being constructed. Work will begin on electrical equipment, control systems and mechanical equipment once the powerhouse is completed. Over 200 employees will be active on the Þeistareykir project at its peak.

The first turbine is expected to come online in the end of 2017 and the second unit in April, 2018. The Þeistareykir Geothermal Power Station is expected to have an installed capacity of 90MW.

An emphasis on successful finishing work

Work on re-vegetation projects for the roadside and roadside extraction areas at Þeistareykir has also been ongoing alongside these other projects.

Land reclamation projects began as a result of any land lost due to the construction of the power station and the first of these projects were completed in cooperation with the municipalities of Þingeyjarsveit and Norðurþing, in the summer of 2014.

This work will continue. A 5 year plan has been developed for the reclamation of grazing land. Landsvirkjun has also developed a project for carbon sequestration, via re- vegetation and forestry projects in the Þeistareykir area.

Safety and environmental matters at the forefront

Landsvirkjun is a leading company in health and safety matters (HSE). Landsvirkjun follows a zero-tolerance policy with a focus on employee wellbeing in the workplace. The policy is a priority and is a key factor in creating a positive work environment.

One of Landsvirkjun's goals is to create an accident-free workplace at Þeistareykir via an active safety system, supervision and training. All employees at the Þeistareykir site attend an HSE induction course. Five hundred and sixty employees had completed the course by the 1st of July, 2016 and this included almost half of the foreign workers.

All on-site contractors take an active part in implementing these safety measures by operating in accordance with Landsvirkjun's safety policy, registering all accidents, near-misses and dangerous circumstances. Learning from these occurrences is believed to be a key factor in preventing future incidents.

Landsvirkjun hopes to continue its progress in HSE practices at Þeistareykir by supporting a cooperative effort between employees and management.

About Þeistareyki

Inhabitants and resources

The first reference to inhabitants in the Þeistareykir area and on the Mælifell Farm can be found in the church inventory of the Múlakirkja Church. The source indicates that the area was inhabited during the 14th and 15th century.

Mælifell was a farm beneath a ‘fell’ with the same name beneath the Lambafjall Mountains in the Middle Ages. The area was abandoned at the end of the 15th century. The area then served as a summer grazing area with outbuildings for the farm Reykir in the Reykjahverfi area. Traces of the farm, summer outbuildings and ruins can be seen to the west of Mælifell.

The Þeistareykir area was probably continuously inhabited during the 16th and 17th centuries. The area was inhabited intermittently during the 18th century and was abandoned in 1873. The Þeistareykir land was utilised until 1955. The farm has been utilised as a summer grazing area for the Aðaldæla & Reykdælahreppur County since 1914 and five thousand sheep graze there during the summer.

There are 58 registered heritage sites on the Þeistareykir land and an outlaying church is believed to have been built in the area during the 14th and 15th centuries, although the location is unknown. The area is considered to be one of the most notable heritage sites in Iceland.

Distinct geological formations

The Þeistareykir area has a very active fumarole area. Hot springs can be found to the north of the Bæjarfjall Mountain, stretching eastward up to Bóndhól and the Ketilfjall Mountain and westward alongside Tjarnarás. Clay pools and solfataras are the most common types found in the area. The geothermal area in Þeistareykir is registered in the Icelandic Nature Conservation Register.

Stóravítisdyngja (Þeistareykjabunga) is one of the largest shield volcanoes in Iceland; approx. 20- 50 km ³. It originates from Stóravíti and Langavíti and the lava area borders with the Gæsafjall Mountains to the south, the Lambafjall Mountains to the west, the Kelduhverfi area to the north and by the Hrútafjall Mountains to the east. The surface are of the lava is approx. 525 km2.

The Þeistareykir lava flowed from the crater in Stórahver and the lava is mostly pahoehoe lava and covers an area of 28 km². The average thickness of the lava is less than 40 m and the volume is approx. 1 km³. The main characteristics of the lava include the so-called rounded hills and a long curved chain of lava formations northward from the crater. The Þeistareykir lava field is the youngest lava field in the area or approx. 2,400 years old. Older lava in the area can be traced back to the end of the Ice Age between10, 000 to 14,000 years ago.

There are a number of caves in the Þeistareykir lava field, including stalactite caves. Stalactite formations hang from the ceiling of the cave and form candle like stacks on the cave floor and sills. Stalactites are protected and breaking or damaging them is prohibited. The caves can be dangerous to enter.

Sumphur mines in the Þeistareykir area

Gun powder production began in Europe in the 14th century. Gun powder and firearms changed European warfare forever. Sulphur is an important raw material of gunpowder. Dutch and English merchants collected sulphur from Iceland but the Danish king eventually took over the sale of all sulphur in 1560. The Danes were involved in an ongoing war with neighbouring countries and we can assume that Icelandic sulphur became one of the foundations of the Danish empire.

Sources reveal that sulphur export was active in the 13th century in Iceland and traces have been found during sulphur cleaning projects in Gásum in Eyjafjörður. Sulphur was also processed in Krýsuvík, on the Reykjanes Peninsula, but the main processing line was in the Þingeyjar Municipality. The Þeistareykir mines were closest to the export harbour in Húsavík but more sulphur- rich mines were found in the Mývatn area; the Hlíðarnámur Mines by the Námafjall Mountain, the Fremrinámur Mines to the east of the Bláfjall Mountain and the Krafla Mines. However, sources also reveal that work procedures were so poor that extraction was hampered by the damage caused to the mines.

The sulphur was processed in Húsavík during the 17th, 18th and 19th centuries and so-called ‘sulphur houses’ were still standing in 1870. Húsavík has been an industrial and export harbour since then.

The sulphur business was profitable. The dividends from one shipment of sulphur could reach half a billion today but the farmers in the Þingeyjar area received little reward for mining and delivering the sulphur to Húsavík.

Eventually, sulphur mines in Sicily became more popular than the sulphur mines in the rather primitive high temperature areas in Iceland. Sulphur mining was discontinued in Þeistareykir towards the end of the 19th century but attempts were made at selling unprocessed sulphur in the middle of the 20th century. The project was cut short and this marked the end of Iceland’s sulphur trade.

Reports and research

Name Date Format Size
Styrkur brennisteinsvegnis í andrúmslofti í Reykjahlíð, Vogum, Kelduhverfi og á Húsavík 05.03.2020
Siesmic Monitoring in Krafla, Námafjall and Þeistareykir 01.02.2020
Háhitasvæðin á Þeistareykjum, í Kröflu og Námafjalli 01.12.2019
Lífríkisvöktun á háhitasvæðum í Suður-Þingeyjasýslu árið 2019 01.11.2019
Vöktun hljóðstigs við jarðvarmavirkjanir 01.08.2019
Noise monitoring at Geothermal power plants 01.08.2019
Þeistareykjavegur nyrðri og virkjunarsvæði - Uppgræðsluaðgerðir 2018 og áætlaðar aðgerðir 2019 26.02.2019
Styrkur brennisteinsvetnis í andrúmslofti í Reykjahlíð, Vogum, Kelduhverfi og á Húsavík - Niðurstöður mælinga árið 2018 06.02.2019
Hita- og loftmyndir af Þeistareykjum teknar með dróna í nóvember 2018 31.01.2019
Háhitasvæðin á Þeistareykjum, í Kröflu og Námafjalli - Vöktun á yfirborðsvatni og grunnvatni árið 2018 31.12.2018
Lífríkisvöktun á háhitasvæðum í Suður-Þingeyjarsýslu árið 2018 30.11.2018
Styrkur brennisteinsvetnis í andrúmslofti í Reykjahlíð, Vogum, Kelduhverfi, á Húsavík og á Þeistareykjum., Niðurstöður mælinga árið 2017 11.04.2018
Þeistareykjavegur nyrðri og virkjunarsvæði, Uppgræðsluaðgerðir 2017 og áætlaðar aðgerðir 2018 og 2019 28.03.2018
Háhitasvæðin í Kröflu, Námafjalli og á Þeistareykjum. Vöktun á yfirborðsvirkni og grunnvatni árið 2017 28.12.2017
Þeistareykjavegur - Mat á uppgræðslu vegfláa með gróðurtorfum 20.12.2017
Gróður- og fuglavöktun á háhitasvæðum í Þingeyjarsýslum árið 2017 20.12.2017
Seismic Monitoring in Þeistareykir, Krafla and Námafjall 12.06.2017 pdf 1.56 MB
Gróður- og fuglavöktun á háhitasvæðum í Þingeyjarsýslum árið 2016 - Minnisblað 19.05.2017
Háhitasvæðin í Námafjalli, Kröflu og á Þeistareykjum - Vöktun á yfirborðsvirkni og grunnvatni árið 2016 24.03.2017 pdf 21.61 MB
Structural Drilling Targets from Platforms A, B, and F at Þeistareykir - Northern Rift Zone and Tjörnes Fracture Zone 24.03.2017 pdf 11.57 MB
Þeistareykjavegur nyrðri og virkjunarsvæði Þeistareykjavirkjunar - Uppgræðsluaðgerðir 2016 og áætlaðar aðgerðir 2017 24.03.2017 pdf 4.43 MB
Lífríki tjarna á Þeistareykjum 2016 24.03.2017 pdf 3.45 MB
Styrkur brennisteinsvetnis í Reykjahlíð, Vogum, Kelduhverfi og á Húsavík - Úrvinnsla mælinga 2016 24.03.2017 pdf 4.84 MB
Þeistareykir - Well ÞG - 11 Phase 2: Drilling for Production Casing from 304 m to 802 m Depth 27.10.2016 pdf 11.98 MB
Gróður- og fuglavöktun á háhitasvæðum í Þingeyjarsýslum árið 2015 - Minnisblað 18.04.2016
Multidisciplinary Structural Analysis and Drilling Targets at Þeistareykir 16.03.2016 pdf 22.78 MB
Þeistareykjavegur nyrðri og virkjunarsvæði - Uppgræðsluaðgerðir 2015 og áætlaðar aðgerðir 2016 09.02.2016 pdf 4.17 MB
Þeistareykjavirkjun - Yfirlit yfir framkvæmdir sumarið 2014 04.12.2015 pdf 5.29 MB
Þeistareykjavegur syðri - Landmótunarfrágangur vegar frá virkjun við Þeistareyki að Kísilvegi 11.03.2015 pdf 3.9 MB
Tectonic Control of the Alteration, Gases, Resistivity, Magnetics and Gravity in Þeistareykir Area 01.03.2015 pdf 16 MB
Þeistareykjavegur nyrðri og virkjunarsvæði - Uppgræðsluaðgerðir 2014 og áætlaðar aðgerðir 2015 13.02.2015 pdf 3.67 MB
Samráðsfundur með ferðaþjónustuaðilum vegna framkvæmda við Þeistareyki 13.02.2015 pdf 2.7 MB
Gróður- og fuglavöktun á háhitasvæðum í Þingeyjarsýslum árið 2014 31.01.2015
A Sensitivity Analysis of the Þeistareykir Reservoir Model 01.09.2014 pdf 2.94 MB
Development of well-bore model for use in conjunction with ITOUGH2. 01.09.2014 pdf 4.67 MB
Gróður- og fuglavöktun á háhitasvæðum í Þingeyjarsýslum árið 2013 31.05.2014
Reykjaheiði - Þeistareykjavegur nyrðri: Frágangur og umbætur á svipmóti 01.04.2014
Preliminary Fracture Analysis of Þeistareykir Geothermal Field and Surroundings, Northern Rift Zone and Tjörnes Fracture Zone 14.12.2013 pdf 12.6 MB
Háhitasvæðin í Námafjalli, Kröflu og á Þeistareykjum: vöktun á yfirborðsvirkni og grunnvatni árið 2013 01.12.2013 pdf 16.94 MB
Þeistareykjavirkjun: prófun ferskvatns fyrir kælivatnshringrás virkjunar 01.06.2013 pdf 1.17 MB
Þeistareykir: afkastamat 2010-2012 01.06.2013 pdf 3.95 MB
Gróður- og fuglavöktun á háhitasvæðum í Þingeyjarsýslum 01.04.2013 pdf 3.75 MB
Rannsóknir á ferðamálum á virkjanasvæði við Þeistareyki 01.04.2013 pdf 1.53 MB
Reiknilíkan af jarðhitakerfinu á Þeistareykjum og frummat á afkastagetu 11.10.2011 pdf 8.86 MB
Mat á umhverfisáhrifum - Þeistareykjavirkjun allt að 200 MWe jarðhitavirkjun í Þingeyjarsveit og Norðurþingi 01.10.2010 pdf 18.31 MB
Greining landslags á fyrirhuguðum framkvæmdasvæðum í Þingeyjarsýslum 04.03.2010 pdf 4.44 MB
Háspennulínur (220 kV) frá Kröflu og Þeistareykjum að Bakka við Húsavík Jarðstrengur (132 kV) frá Bjarnarflagi að Kröflu 04.03.2010 pdf 63.5 MB
2010 grunnvatnsrannsóknir 04.03.2010 pdf 3.99 MB
Sameiginleg tillaga að matsáætlun 04.03.2009 pdf 4.91 MB
Mat á umhverfisáhrifum Tillaga að matsáætlun 04.03.2009 pdf 2.51 MB
Virkjunarkostir á háhitasvæðum við Mývatn, Gjástykki og Þeistareyki 2009 04.03.2009 pdf 7.99 MB
Afmörkun á jarðhitagróðri við Þeistareyki 04.03.2009 pdf 14.47 MB
Hugmyndalíkan jarðhitakerfisins á Þeistareykjum og jarðvarmamat með rúmmálsaðferð 01.06.2008 pdf 6.11 MB
Mat á umhverfisáhrifum Tillaga að matsáætlun 04.03.2008 pdf 0.4 MB
Gróðurfar á háhitasvæðum og fyrirhuguðum línu- og vegstæðum á Norðausturlandi 04.03.2008 pdf 17.05 MB
Gróðurfar á háhitasvæðum og fyrirhuguðum línu- og vegstæðum á Norðausturlandi 04.03.2008 pdf 19 MB
Fuglalíf á framkvæmdasvæðum fyrirhugaðra háhitavirkjana í Þingeyjarsýslum 04.03.2007 pdf 15.67 MB
Deiliskráning vegna framhvæmda við línustæði 2007 04.03.2007 pdf 12.27 MB
Gróður og smádýr á sex háhitasvæðum 04.03.2003 pdf 8.65 MB

Air quality monitoring

  • Monitoring on hydrogen sulphide levels has been conducted in the Kelduhverfi area since December, 2011. A hydrogen sulphide monitoring station was installed in Húsavík at the Skiing chalet in Skálamel in March, 2015. The purpose of monitoring is to gather basic information about the concentration of hydrogen sulphide in the atmosphere, before geothermal energy production begins at Þeistareykir and subsequently to monitor the concentration of hydrogen sulphide in the atmosphere when geothermal energy has begun. The installation of the monitoring station is in accordance with Regulation 514/2010. The graph below shows the monitoring results.

The calibration of measuring devices is completed annually by an authorised body and the device resets itself once a week.

The results from measurements of H2S conducted at Husavik and the Kelduhverfi area in 2015. These are preliminary results: