Hydro and geothermal energy

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Hydro and geothermal energy


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Landsvirkjun energy sources

Renewable energy in Iceland

The highest concrete-faced rockfill dam in Europe forms Hálslón Reservoir, the main reservoir for the Fljótsdalur Power Station.

Water from the reservoir runs through a tunnel where it falls vertically more than 400 metres to the station’s turbines.

Icelanders generate 99% of their electricity using renewable resources. Landsvirkjun generates two-thirds of that energy, mostly by means of hydropower, but also by geo-thermal power.

Landsvirkjun’s aim is to be a leader in the sustainable harnessing of renewable energy sources in Iceland.

Our role is to maximise the returns from the energy sources entrusted to us, through sus-tainable use, value creation and efficiency.

1. Geothermal 4%

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2. Hydropower 96%

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Hydropower

1 Fljótsdalur Station 690 2007

2 Búrfell Station 270 1969

3 Hrauneyjafoss Station 210 1981

4 Blanda Station 150 1991

5 Sigalda Station 150 1977

6 Sultartangi Station 120 1999

7 Vatnsfell Station 90 2001

8 Írafoss Station 48 1953

9 Steingrímsstöd Station 26 1959

10 Ljósafoss Station 15 1937

11 Laxá III Station 14 1973

12 Laxá II Station 9 1953

13 Laxá I Station 5 1939

Hydropower 1,797

Geothermal Power

14 Krafla Station 60 1977

15 Bjarnarflag Station 3 1969

Geothermal Power 63

Total 1,860

Landsvirkjun operates a total of 13 hydropower stations and two geothermal stations. The annual energy production is approximately 12.000 GWh, and the company is the eighth largest in the field of renewable energy in Europe.

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Power stations Capacity MW On-line

76

Turbine

Borehole

Generator

Reinjection1

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3

4

Electricity generated from geothermal energy

1. Steam is led from boreholes to turbines in the powerhouse.

2. The pressure and heat difference in the steam drives the turbines.

3. The turbine drives the magnetised rotor inside the generator.

Surrounding the rotor are copper coils and when the magnet

is in motion, electrical current starts to run through the coils.

4. Electricity is carried along high-voltage transmission lines to

the electricity grid.

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Geologically, Iceland is relatively young. The country is a volcanic island, located on a hotspot on the Mid-Atlantic Ocean Ridge, where the North American and Eurasian plates meet. Geothermal heat is considerable in most parts of the country, and in many places hot water from just below the surface is used to heat homes and for energy production.

When precipitation runs through the hot bedrock, the water heats up, resulting in hot springs on the surface and steam chambers underground. In low-temperature areas, hot water is primarily used to heat homes,

while high temperature areas produce hot steam under pressure.

Steam is led from boreholes to turbines inside the powerhouses of geothermal plants, transforming thermal energy into electricity.

The total installed capacity of geothermal energy in Iceland is 575 MW. Landsvirkjun operates two geothermal plants with an installed capacity of 63 MW.

Harnessing geothermal energyEnergy from the Earth’s core

The high temperature areas are located near the tectonic plate boundaries, while the low-temperature areas are further away.

High temperature

Low temperature

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A year after construction work began at Krafla, the ground opened in a volcanic eruption only three kilometres away from the station.

The eruption sent corrosive magma vapours into the geothermal system that destroyed the borehole linings. A series of nine volcanic

eruptions began on 20 December 1975 and lasted until September 1984.

The seismic and volcanic impact was reduced once the eruptions ceased. In 1996, Landsvirkjun decided to install the second turbine unit and

prospect for more steam. Work began immediately with improved technology. Methods used included directional drilling, a process that has

proved quite successful. New holes were drilled and older ones repaired. The results were good and sufficient steam to drive the station’s

second turbine was obtained.

The Bjarnarflag Geothermal Station in the Lake Mývatn area is the smallest geothermal station owned by Landsvirkjun and the first of its kind in Iceland. The station generates 3 MW, using the steam from the geothermal area near Námafjall Mountain.

In addition to generating 18 GWh of electricity annually, Bjarnarflag provides steam for the local district heating system and industrial use, as well as geothermal water for the nature baths at Lake Mývatn.

Krafla Power StationAt Krafla Power Station, high- and low-pressure steam from 18 boreholes drives two 30 MW turbines.

Built by the Icelandic government, Krafla came under the ownership of Landsvirkjun in 1985. Construction began with trial bore-holes in 1974, the first turbine unit started up in August 1977, and regular operations began in February 1978. Krafla’s development was a pioneering endeavour, hampered by political feuds for years, as well as volcanic activity and technical complications.

The installation of the station’s second tur-bine unit began in 1996. New boreholes weredrilled and older ones were repaired. Steamextraction has been successful with improvedtechnology, among those being directionaldrilling. Since additional drilling and reno-vations were completed in 1997, Krafla has been operated at its full 60 MW capacity.

Bjarnarflag Power Station

Krafla Power Station 1977/1997

Installed capacity 60 MW

2 steam turbines 2x30 MW

Generation capacity 500 GWh p.a.

Bjarnarflag Power Station 1969


1 steam power unit 3 MW


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Reservoir

Outflow

Turbine

Penstock pipe

Generator

Electricity generated from hydropower

1. The reservoir behind the dam maintains the water level and creates pressure.

2. The water flows down the penstock pipes and drives the turbine wheel.

3. A turbine drives the magnetised rotor inside the generator. Copper coils surround the rotor,

and as the magnets turn, an electrical current begins to flow through the coils.

4. The generator now produces electricity that is then carried along high-voltage lines

to the electricity grid.

5. Finally, the water flows from the powerhouse.

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Water that collects at an altitude of up to 800 metres above sea level, releases an enormous amount of energy as it travels down from the highlands. Landsvirkjun operates 13 hydropower stations of varying sizes and types that harness this energy.

Roughly 80% of the energy generated goes to energy-intensive industries, and the rest is distributed to households and smaller businesses. The total installed capacity of Landsvirkjun’s hydropower stations is approximately 1800 MW.

Harnessing waterwaysRiver power

Landsvirkjun’s Hydropower Stations

Ljósafoss, Írafoss and Steingrímsstöd

Blanda

Laxá I–III

Fljótsdalur

Búrfell, Sultartangi, Hrauneyjafoss,

Sigalda and Vatnsfell

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The start-up of Ljósafoss Station in 1937 quadrupled the supply of electricity in the Reykjavík city area. The electricity produced from the river

Ellidaá in the days before Ljósafoss was primarily used for lighting. The addition of Ljósafoss opened up the possibility of using electric stoves

instead of coal stoves in Icelandic homes. To create a market for the electricity from the station, households were given the option of obtaining

a Rafha electric stove with their electricity subscriptions.

Ljósafoss and Írafoss Power StationsThe oldest power station in the River Sog is located near Ljósafoss by Lake Úlfljótsvatn’s outflow. The station is located on the river bank east of the waterfall, and the water runs through pipes to the station’s turbines and from there into the river below the waterfall.

Operation of the Ljósafoss station began in 1937, when two turbine units were installed with a combined capacity of 8.8 MW. The third turbine was installed in 1944 with 6.5 MW.

The Írafoss Station harnesses two of the water-falls, Írafoss and Kistufoss, in the lower part of the River Sog. A dam has been built across the River Sog above Írafoss at virtually the same altitude as the Ljósafoss Station outflow.

The station went on-line in 1953 using two 15.5 MW generating units and was expanded with the addition of a 16.7 MW turbine in 1963.

Steingrímsstöd Power StationThe Steingrímsstöd Station is the third station built in the River Sog area. The station harnesses the head where the Upper Sog drains from Lake Thingvallavatn into Lake Úlfljótsvatn. A dam was built at the outflow of Lake Thingvallavatn, with the headrace tunnel running through Dráttarhlíd, which separates Lake Thingvallavatn and Lake Úlfljótsvatn, and into an open-air surge

Steingrímsstöd Station

Ljósafoss Station

Írafoss Station

pond above the powerhouse. The outflow from Lake Thingvallavatn is on average approximately 100 m3/s.

The station came on-line in 1959, and the installed capacity is 27 MW.

Ljósafoss Station 1937 / 1944


3 Francis turbines 2x4.4 MW and 6.5 MW


Head 17 m

Maximum flow 104 m3/s

Írafoss Station 1953 / 1963


3 Francis turbines 3x16 MW


Head 38 m


Steingrímsstöd Station 1959


2 Kaplan turbines 2x13.5 MW


Head 20.5 m


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Ideas for harnessing the River Blanda were originally proposed around 1950. The Blanda Hydro Station is the first large-scale power station

that is entirely of Icelandic design. The first turbine units were brought on-line in the autumn of 1991, and the station had reached full

operational capacity by March 1992.

Blanda Power Station




Total head 287 m


Blanda Reservoir

Maximum area 56 km2

Live storage 412 Gl

Blanda dam

Dam height 44 m

Dam length 800 m

Gilsárlón Reservoir

Area 5 km2

Live storage 20 Gl

Kolka dam

Dam height 25 m

Dam length 1300 m

Gilsárlón Reservoir

Blanda Station

Blanda Station 1991

The Blanda Station came on-line in 1991. It is located on the northern edge of the high-lands near the end of the Kjalvegur Mountain Road. To the north is a view over the Blöndu-dalur Valley where the River Blanda flows out to the sea near the town of Blönduós. The Blanda Station is an underground plant, located approximately 230 metres below the surface.

The river flows through grassy fields in the lowlands, but its source is in a region that only a few decades ago was a desert. After the creation of a 56 km2 storage reservoir, extensive revegetation efforts were initiated. Since 1981, Landsvirkjun has cultivated over 5000 hectares at an altitude of 400–600 m by fertiliser treatment and sowing. This is one of the most extensive reclamation projects ever undertaken in Iceland’s highlands.

A dam was built in the River Blanda near the Reftjarnarbunga Hill, an ideal area for a reser-voir. A dam was also built near the source of the River Kolkukvísl which flowed into River Vatnsdalsá. These dams formed the Blanda Reservoir, which has a live storage capacity of 412 Gl and is the third-largest lake in Iceland. From the Kolka Dam, the water is diverted through diversion canals and lakes on a 25 km long route to the station’s intake reservoir, Gilsárlón. The reservoir has an area of 5 km2 and has a live storage capacity of 20 Gl.

From the intake reservoir, water runs through a 1300 m long canal to the station’s intake, where it is diverted to the turbines in the powerhouse. The drop to the turbines from the harnessed head is 287 m. From the turbines, the water is lead through a 1700 m tailrace tunnel back into the river course.

Blanda Reservoir

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Ufsarlón Reservoir

Maximum area 1 km2

Live storage 3 Gl

Kelduárlón Reservoir

Maximum area 7.5 km2

Live storage 60 G

Fljótsdalur Station came on-line in 2007. The Station’s catchment area covers over 2200 km2 and the station’s reservoirs are formed by five dikes that are over five kilo-metres in length. The water is diverted to the Fljótsdalur Station’s turbines from the reservoirs in the highlands north of the Vatnajökull Glacier, through a tunnelsystem that is approximately 72 km long.

Kárahnjúkar Dam is the tallest concrete-faced rockfill dam in Europe and among the largest of its kind in the world. The River Jökulsá á Dal is dammed at Fremri Kárahnjúkar with the largest of the Kárahnjúkar dams. Most of the rockfill was quarried just upstream of the dam within the reservoir area and placed in compacted layers. During construction, the river was diverted through two diversion tunnels under the dam on the western bank.

Two smaller saddle dams were built at Kárahnjúkar, Desjará Dam to the east and

Saudárdalur Dam to the west. Together, the three dams form the Hálslón Reservoir which covers an area of 57 km2, and reaches all the way to the Brúarjökull Glacier.

Most years, Hálslón fills up in late summer.When this happens, the spillover is diverted through a chute down to the canyon edge, where it becomes the waterfall Hverfandi (Vanisher). Almost 100 metres high, Hverf-andi can, at times, become more powerful than Dettifoss, its neighbour to the north and one of Europe’s most powerful waterfalls.

The water from all the reservoirs comes together in the headrace tunnel, which runs almost level at 100-200 metres depth under the Fljótsdalsheidi Moor. The headrace tunnel ends in two pressure shafts, where the water falls 400 metres vertically into the Fljótsdalur Station’s Powerhouse, about 1 km inside the mountain.

Fljótsdalur Station’s Catchment Area

Hálslón

Area of full reservoir 57 km2

Live storage 2100 Gl

Kárahnjúkar Dam

Maximum dam height 198 m

Dam length 700 m

Desjará Dam


Dam length 1100 m

Saudárdalur Dam


Dam length 1100 m

Hálslón Reservoir

Fljótsdalur Station Tailrace tunnel

Headrace tunnel

Headra

ce tu

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River J

ökulsá

in Fl

jóts

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Lake

Lögu

rinn

Ufsarlón Reservoir

Kelduárlón Reservoir

Grjótárlón Reservoir

Lake Saudárvatn

Desjar

á Dam

Saud

árda

lur D

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River Jökulsá á Dal

Kára

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Fljótsdalur Power StationFour years passed from the beginning of construction work at Kárahnjúkar in 2003 until the Fljótsdalur Power Station reached full operational capacity in 2007. Concurrent with the construction work at Kárahnjúkar, an aluminium plant was built in Reydar-fjördur. Most of the energy generated is sold to the Reydarfjördur plant.

On its long journey from the reservoirs in the highlands to the station’s intake, the water drops approximately 200 m. Two-thirds of the total head runs through an approximately 400 m high vertical pressure tunnel near the Fljótsdalur Station.

The water’s total drop therefore, is more than 600 m. The water drives six powerful turbines in the powerhouse and then flows through a tailrace tunnel and canal into the river Jökulsá in Fljótsdalur, east of Valthjófsstadur Mountain, at an altitude of 26 metres. The underground powerhouse is located inside Valthjófsstadur Mountain and is accessed through an 800 m tunnel. Electricity is transmitted from the station through a separate cable tunnel to the switchgear house and from there through high-voltage lines to Alcoa’s aluminium plant in Reydarfjördur.




Total head 599 m

Maximum flow 144 m3/sec

Fljótsdalur Station 2007 Tunnels

Total 72 km

Headrace tunnel from Hálslón Reservoir

(diameter 7.2–7.6 m) 39.7 km

Headrace tunnel from Ufsarlón Reservoir

(diameter 7.2 m) 13.3 km

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ÞJjó

Bjarnarlón Reservoir

Lake Thórisvatn

Kvíslaveita Reservoir

Hágöngulón Reservoir

Vatnsfell StationVatnsfellslón Reservoir

Sigalda StationKrókslón Reservoir

Hrauneyjafosslón Reservoir

Búðarháls Station

Sultartangi Station

Sultartangalón Reservoir

Búrfell Station

Kaldakvísl River

Thjórsá and Tungnaá Catchment AreaThere are five hydropower stations in the catchment area of Rivers Thjórsá and Tungnaá: Búrfell, Sultartangi, Hrauneyja-foss, Vatnsfell and Sigalda, with combined energy of 850 MW. The sixth, Búðarháls Station, is under construction to be brought on-line in 2013. Water for all the power stations is provided by three main reservoirs, Thórisvatn, Hágöngulón and Kvíslarveita, along with smaller reservoirs connected with each station.

Lake Thórisvatn, Iceland’s largest lake, is the largest reservoir and an important part of Landsvirkjun’s utility system. All water accumulated in Kvíslarveita and Hágöngu-lón reservoirs runs through Lake Thórisvatn.

Lake Thórisvatn became a reservoir with the harnessing of River Thjórsá at Búrfell Mountain in 1970-1972. River Kaldakvísl was diverted into the lake at the northern edge of the lake and a controlled outflow constructed at the southern edge.

Hágöngumidlun area 1997-1999

Hágöngulón Reservoir

Area 37 km2

Live storage 320 G

Lake Thórisvatn

Area (fully utilised) 83 km2

Live storage 1400 Gl

Catchment Area 2783 km2

Maximum depth 109 m

A canal was dug from the lake and a concrete gate structure built in the canal to manage the flow rate. The canal is named the Vatnsfell Canal, and carries water from Lake Thórisvatn through the Vatnsfell Station into the Krókslón Reservoir above the Sigalda Station, and from there to other stations further down in the catchment area.

Work on the Kvíslaveita Reservoir began in 1980 and was completed in 1997. Kvíslaveita is the collective name for the dams, canals, bottom outlets and gate structures that man-age the flow rate from the River Thjórsá and its tributaries into Lake Thórisvatn.

The Háganga Reservoir was constructed in 1997–1999 and covers an area of 27 km2. Its purpose is to increase the efficiency of the catchment area of River Kaldakvísl. During the summer months, water accumulates in the Hágöngulón Reservoir, with very little water flowing down the Kaldakvísl riverbed.

Kvíslaveita 1980-1997

Maximum area 24 km2

Live storage 400 Gl

Area of Thjórsárlón 3.5 km2

Thjórsá/Thórisvatn dam 53 km

Thjórsá

River

Tungnaá RiverHrauneyjafoss

Station

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The front wall of the Búrfell powerhouse is decorated with a mural by artist Sigurjón Ólafsson, who also made the sculpture

“The Noise Troll” (Hávadatröllid) standing in front of it. Visitors are invited to view a multimedia exhibition on renewable energy

sources in the powerhouse’s visitors’ room.

Búrfell Power StationWhen Landsvirkjun was established in 1965, it embarked on the construction of the Búrfell Hydropower Station, which came on-line in 1972. It took almost ten years to complete the construction and it was the largest power station in the country until the inauguration of Kárahnjúkar Hydropower Station in 2007. The River Thjórsá is harnessed at Búrfell with a tailrace tunnel from the Bjarnarlón Reservoir to the powerhouse located in the Thjórsárdalur Valley. The River Thjórsá, which previously flowed south of Mountain Búrfell, is diverted above the mountain into Bjarnarlón Reservoir, and from there through a tunnel passing through the basalt strata of Sámstadamúli into the Thjórsdárdalur valley.

The diversion system in the riverbed of Thjórsá is equipped with a special ice-

barrier structure. In earlier years, the role of the ice barrier structure was to rinse aside ice and slush to prevent it from reaching the Bjarnarlón Reservoir. Today, the flow rate of the river can be better managed and with the construction of a canal between the Sultartangi and Búrfell stations the amount of ice and slush has been reduced. The need for the structure has therefore been greatly diminished.

From the powerhouse turbines, the water exits via draft tubes into a short canal before entering the River Fossá, which joins the River Thjórsá 2 km downstream.

The station’s equipment was partially renewed in 1997-1999. This increased the station’s installed capacity to 270 MW, from 210 MW.



Generation capacity 2,300 GWh p.a.

Total head 115 m

Maximum flow 300 m3/sec

Bjarnarlón Reservoir

Maximum area 1 km2

Live storage 5 Gl

Diversion system in River Thjórsá

Length of installation 370 m

Four spillway gates and two ice gates

Búrfell Station 1972 / 1998

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Sultartangi Power StationThe Sultartangi Station, located 15 km north-east of the Búrfell Station, was built at the end of the last century and came on-line in 1999. The Station utilises water from the River Tungnaá which has already driven the turbines of the Hrauneyjafoss and Sigalda stations on its way down from the highlands. It also utilises the River Thjórsá’s flow rate, as the two rivers are joined in the Sultartanga-lón Reservoir above the station. As a result, it is not as sensitive to fluctuations in water supply as many other stations are. In this regard it resembles the Búrfell Station.

The Sultartangi Dam is the longest in Iceland, 6.1 km in length. In conjunction with the

construction of the power station, the dam crest was raised by 1 metre, increasing the reservoir’s surface area from 18 to 20 km2. A headrace tunnel (3.4 km) moves water from the reservoir through Sandafell Mountain to a surge basin on its southwestern side. At the end of the surge basin is the station intake, where two penstocks lead to the powerhouse.

A tailrace canal, just over 7 km long, lies from the powerhouse at the foot of Sandafell Mountain and follows Thjórsá River almost all the way to the Búrfell Station Reservoir dam where it enters the Thjórsá riverbed.




Total head 44.6 m


Sultartangi Station 1999 Sultartangalón Reservoir

Maximum area 20 km2

Live storage 109 Gl

Dam

Dam height 23 m

Dam length 6100 m

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The Hrauneyjafoss Station is Iceland’s third largest power plant, producing 210 MW. It is located near the Sprengisandur Route on the edge of the highlands; southwest of the Sig- alda Station, and utilises the same water as Sigalda Station. Hrauneyjafoss Station came on-line in 1981.

The Tungnaá River is dammed on rather flat land approximately 1.5 km above the Hraun-eyjafoss Waterfall and 7 km below the Sigalda Station. The difference in altitude is approx-imately 15 m. Hrauneyjalón, an 8.8 km² reservoir, was formed by the dam. A low

soil wall dam stretches along the lava flat-lands on the south bank of the river. A headrace channel runs 1 km northwards from the reservoir through a dip in the Fossalda Hill to an intake point at its northern edge. Three steel penstocks (4.8 m in diameter) run 272 m down the hill to the powerhouse. The tailrace canal, just over one kilometre in length, enters the Spordöldukvísl waterway, which runs into the Tungnaá River.




Total head 88 m


Hrauneyjafoss Power Station

Hrauneyjafoss Station 1981 Hrauneyjalón Reservoir


Live storage 33 Gl

Hrauneyjafoss dam

Dam height 15 m

Dam length 3000 m

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There have been plans for power development in River Thjórsá for a long time. Einar Benediktsson, an Icelandic poet and entrepreneur, was probably

the first person to seriously consider harnessing the river with his company Títan in the early 20th century. Around 1960, Thjórsá development was

given serious consideration, but national use of electricity was too limited to fully utilise the energy that could be harnessed. As a result, ideas were

put forward to use the development for heavy industry to ensure its economic viability.

Sigalda Power StationThe Sigalda Station is located just above the Hrauneyjafoss Station, south of Lake Thóris-vatn. The station came on-line in early 1978. A short tailrace canal links Sigalda Station with Hrauneyjafoss Station.

Sigalda Station was built following the devel-opment at Búrfell. Its construction was a race against time as there was great demand for more hydropower stations to satisfy energy requirements in Iceland following the power-intensive industrial growth in Straumsvík and Hvalfjördur.

The Sigalda Dam dams the Tungnaá River at the top of the canyon above Sigalda Hill, where it forms Krókslón, a 14 km2 reservoir. The rock-fill dam is 925 m long, clad with asphalt, and 40 m tall at its highest point. The water is carried 1 km through an intake canal from Krókslón Reservoir to the western edge of Sigalda Hill. Three pressure shafts, 216 m long and 4.3 m in diameter, run to the powerhouse north of the old riverbed, in part buried inside the Sigalda hillside. The harnessed head is 74 m. A 550 m tailrace canal leads from the powerhouse into the Hrauneyjafoss Reservoir.




Total head 74 m


Sigalda Station 1978 Krókslón Reservoir

Area 14 km2

Live storage 140 Gl

Dam

Dam height 42 m

Dam length 925 m

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Vatnsfell Power StationThe Vatnsfell Station began operations in 2001, with construction work beginning in 1999. The station’s capacity is 90 MW, and it is the northernmost power station in the Thjórsá and Tungnaá River area.

Vatnsfell Station utilises the head in the diversion canal between the Thórislón Reservoir and Sigalda Station’s reservoir Krókslón. Unlike the other stations, it only produces electricity during winter.




Total head 65 m


Vatnsfell Station 2001

m.a.s.l.

180 140160 120 100 80 60 40 20 0 km

Hágöngumidlun Reservoir

Kvíslaveita

Kaldakvísl River

Thórisvatnsmidlun reservoirs

Thjórsá River

ReservoirDam

Canal /pipe

Power Station

Tungnaá River

1. Vatnsfell 90 MW

2. Sigalda 150 MW

3. Hrauneyjafoss 210 MW

4. Sultartangi 120 MW

5. Búrfell 270 MW

Power Stations

Harnessed head and power stations in the rivers Thjórsá and Tungnaá

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Vatnsfellslón Reservoir


Live storage 3 Gl

Dam

Dam height 30 m

Dam length 750 m

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Laxá Power Stations I, II, and IIIThe three Laxá Stations harness a 70 m head on an 1800 m strecth of River Laxá to produce a total of 27.5 MW of electricity. The in-flow to Lake Mývatn is mostly underground, through layers of lava, largely immune from seasonal fluctuations and ideal for harness-ing hydropower.

Laxá I and II are low head hydro stations that harness the natural flow of River Laxá. Station III, the latest addition, utilizes the same head as Laxá I but runs its water through a tunnel to the power station, 60 metres inside the rock.

The town of Akureyri and the Icelandic Gov-ernment built the Laxá Stations which joined Landsvirkjun in 1983.

Laxá Stations I and II The Laxá I Station is the oldest power plant in the river Laxá. From the dam at the top of the canyon, the water is first diverted through an underground tunnel and then through a channel approximately 670 m in length,

leading to the power station. The station operates two turbine units, coming on-line in 1939 and 1944. For the Laxá II Station, the river is dammed 300 metres below Laxá I, diverting the water 380 metres to the power station via a penstock and a surge tank.

Laxá III StationThe Laxá III Station is the most recent power station in the river Laxá. The underground vault housing the station’s turbine unit was initially designed for two 25 MW turbines. The plans called for the construction of a 56 m high dam in the upper part of the canyon, making the total head 83 m. The local population of Þingeyjar strongly pro-tested the plan. The Laxá III Hydropower Station was inaugurated in 1973 with one turbine instead of two, and further plans for the region were shelved.

Laxá I 1939


2 Francis turbines 2x2.5 MW


Total head 39 m

Laxá II 1953


1 Francis turbine 9 MW


Total head 29 m

Laxá II Station

Laxá Stations I and III

Laxá III 1973

Installed capacity 13.5 MW

1 Francis turbine 13.5 MW


Total head 39 m

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Magnetic poles

Electrical current

Stator Gene

rato

rFr

anci

s tu

rbin

e

Copper coils

Turbine wheel

Draft tube

Water flow

Penstockpipe

Shaft

The Francis turbine

Most of Landsvirkjun’s stations use

Francis turbines. In such turbines, the

water is diverted through a penstock

pipe to the turbine wheel which is driven

under considerable pressure. From the

turbine wheel, the water is lead through

a draft tube that further increases the

pressure on the wheel.

The turbine wheel connects to a shaft

that drives a magnetic rotor surrounded

by copper coils. The rotation causes an

electrical current to pass through the

coils, transforming kinetic energy to

electricity, which is distributed to the

transmission system.

Units of measurement

MW = megawatt 1 MW = 1,000 kW = 1,000,000 W

kW = kilowatt Power is measured in watts and describes the ability to perform work.

W = watt Power describes the capacities of the turbines in a power station.

TWh = terawatt hours 1 TWh = 1,000 GWh = 1,000,000 MWh = 1,000,000,000 kW

GWh = gigawatt hours

MWh = megawatt hours The amount of electricity produced or consumed is measured in watt hours.

kWh = kilowatt hours

kV = kilovolt 1 kV = 1,000 V

V = volt Current is measured in volts. The current in the country’s most powerful

high-voltage lines is 220 kV.

Gl = gigalitre 1 Gl = 1,000,000,000 l = 1,000,000 m3

l = litre Capacity in reservoirs are measured in gigalitres.

m3 = cubic metre

The printing of this brochure has Nordic Swan

Ecolabel accreditation.

The paper used for the brochure has Nordic Swan

Ecolabel accreditation and carries the FSC label.

Paper: Munken Polar, 170 gr.

Design: Jónsson & Le’macks

Printing: Prentmet

January 2012

ECO LABELLING

Printing company

141 858

36

Landsvirkjun

Háaleitisbraut 68103 ReykjavíkIcelandTel: +354 515 9000

[email protected]



Hydro and geothermal energy

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Transcript of Hydro and geothermal energy