User:Semuestra/Axpo Power

Axpo Power AG with headquarters in  Baden, Canton of Aargau is a 100 per cent subsidiary of Axpo Holding. The company produces, distributes and sells electricity as well as other energy and provides energy-related services.

Axpo Power originates from Nordostschweizerische Kraftwerke AG (NOK), later known as Axpo AG. NOK  has its origins  in Kraftwerke Beznau Löntsch AG, founded in 1907.

History
→ Main article Axpo history see Axpo Holding AG

Motor AG für angewandte Elektrizität completed construction of the Aare power plant at Beznau in 1902 and in 1908 the power plant on the Löntsch river. The company then founded a common company, Beznau Löntsch AG. The power plant on the Löntsch river uses the Klöntalersee, a natural lake created by a rockslide. The two power plants were interconnected with high-voltage lines to the second power grid in Switzerland.

In 1914, the cantons of Aargau,  Glarus, Zurich, Thurgau, Schaffhausen and Zug took over the Kraftwerke Beznau-Löntsch and named the new company NOK. The Canton of Schwyz originally wanted to participate in the project, but the canton council did not approve. Beznau is still one of the most important substations in the 380-kV transmission grid today. In 1929, St. & nbsp;  Gallisch-Appenzellische Kraftwerke AG (SAK), which was founded in 1914, joined NOK, and was followed later by the Canton of  Appenzell-Innerrhoden in 1951.

In the 1960s, Swiss authorities, NOK and other large power producers came to the conclusion that hydropower was largely exhausted as an electricity source. The focus was now on fossil fuel power plants and nuclear power.

Owing to the accident in the Lucens research nuclear power plant it would not be possible to realise Switzerland's reactor plans; NOK looks to American light-water reactor technology for the Beznau power plant.

Switzerland's first nuclear power plant, Beznau 1, goes into operation in 1969. Beznau 2 follows in 1971. The break-through for nuclear power enjoyed broad political support, including from environmentalists that wanted to contain construction along rivers and streams and reduce the increasing CO2 pollution in the air.

In 1997, the EU initiates the gradual liberalisation of the power market. In order to turn NOK into a Europe-competent power company, NOK as well as the NOK cantons and their utilities found Axpo Holding AG in 2001. In 2009, NOK becomes Axpo AG and, in 2011, today's Axpo Power AG.

In the course of liberalisation, ownership and operation of the transmission grid is unbundled from the distribution, power production and trading business. At the beginning of 2013, the transmission grid is transferred to the national grid company Swissgrid, which was founded in 2006. Axpo Power AG holds an interest of 22.7% in Swissgrid.

Shareholders
Axpo Power AG is a joint undertaking on the part of the following institutions: Canton of Zurich (share 18.342 %), Public utilities of the Canton of Zurich (18,410 %), Canton of Aargau (13.975 %), Aargauisches Elektrizitätswerk (14.025 %), St. Gallisch-Appenzellische Kraftwerke (12.5 %), Public utility of the Canton of Thurgau (12.25 %), Canton of Schaffhausen (7.875 %), Canton of Glarus (1.747 %) and Canton of Zug (0.873 %).

Power plants and grids
Axpo Power AG operates over 100 power plants. Its Swiss power plant park has an installed capacity of about 5830  megawatts (MW), status at the end of September 2019, and a production capacity of approx. 25 billion kilowatt-hours (kW).

Axpo Power AG's domestic power mix comprising hydropower, nuclear power as well as biomass is nearly CO2-free in operation.

Axpo's supra-regional distribution grid (110 kV/50 kV/16 kV) extends over 2200 kilometres and includes 8000 masts. The grid consists of 82 per cent overhead lines and 18 per cent underground cabling. With its grids, Axpo supplies all of Northeastern Switzerland, the Principality of Liechtenstein as well as parts of the cantons of Schwyz, Zug, Grisons and Valais with electricity.

The average time of a supply interruption per end consumer is low. In financial year 2018/19, this was 0.25 [min/a] for Axpo Grids and 21.6 [min/a] for CKW.

Nuclear power plants
Axpo Power AG holds an interest of 100% in the Beznau nuclear power plant. The company also holds a 22.8 %-interest in the Leibstadt nuclear power plant and is responsible for its management. The company holds 25 % of the share capital of the Gösgen nuclear power plant.

In the 10-year average, the proportion of nuclear energy in power production in Switzerland amounts to 39 per cent, in winter up to 45 per cent. The annual availability rate is approx. 90 per cent. Nuclear power plants generate base load electricity.

Axpo Power AG has an installed capacity of 1500 MW with its nuclear power plants (owned, partner plants and long-term contracts with France).

Reported incidents
Operators of Swiss nuclear facilities must report to the Federal Nuclear Safety Inspectorate ENSI incidents that comply with the criteria according to the Nuclear Energy Ordinance and ENSI policies. Mandatory reporting of incidents point out irregularities in operation that must be monitored and communicated. This does not mean that measurable quantities of radioactive substances have been accidentally released.

According to ENSI, the Swiss power plants were operated safely in 2019.

According to ENSI,  31 incidents that had to be reported occurred in Axpo Power AG nuclear power plants (owned and partner plants) in accordance with  the International Nuclear and Radiological Event Scale INES in 2018.

INES classifies level 0 as a Deviation, levels 1 to 3 as Anomalies and Incidents, and levels 4 to 7 as Accidents. Source: Oversight Report 2018 on nuclear safety in Swiss nuclear power plants, ENSI (the Oversight Report is published annually in June).

Beznau nuclear power plant
The Beznau nuclear power plant (KKB) is owned to 100% by Axpo Power AG. The facility is located on an Aare River island in the Lower Aare Valley. Beznau 1 has been in operation since 1969, Beznau 2 since 1971. Both reactors are pressurised water reactors and each have a gross output of 380 MW, and a net output of 365 MW.

KKB generates about 6 billion kWh of electricity per year. Furthermore, it supplies a region with approx. 18,000 residents with district heat.

According to the Swiss Nuclear Energy Act, Switzerland's power plants have an open-ended operating permit. This means that the nuclear power plants can be operated as long as they are safe to do so.

In 2019, KKB celebrated its 50-year anniversary and is the oldest nuclear facility in the world. Nevertheless, Axpo intends to operate the plant for about another 10 years.

The Federal Government is also called upon to calculate the operating time for Swiss nuclear facility at 60 years (previously 50 years) in order to implement the energy transition. Axpo Power AG  has invested approx. CHF 2.5 billion in retrofitting and renewal of the facility since its commissioning.

Since commissioning, 250 terawatt-hours of electricity have been produced on Beznau Island. A coal-fired power plant would have emitted approx. 300 million tonnes of CO2 into the atmosphere generating this output.

Incidents in the reactor pressure vessel (RPV), Beznau Unit 1
In 2015, Axpo detected notable irregularities on the reactor pressure vessel (RPV) of Beznau 1 using new, previously unavailable ultrasound measurement technology. Axpo suspected that the approx. 950 anomalies were aluminium oxide inclusions that occurred during forging of the pressure vessel in France in 1965. The incident resulted in a reactor downtime of three years. This is how long it took Axpo Power AG to produce an extensive safety case indicating that the findings were not attributable to a safety-technical defect. The safety case and the downtime, as well as the procurement costs for replacement power volumes cost the company CHF 350 million.

The safety case includes a replica of a forged ring manufactured at an English foundry in Sheffield on behalf of Axpo. The replica, based on the specifications for the original ring, was cast, forged, heat-treated and then tested.

After examining the data presented, ENSI together with an independent, international expert group came to the conclusion that the detected irregularities occurred during manufacture and not during operation, and that the RPV was safe (also see: ENSI Oversight Report 2018, statements on the BEFLAW Project, page 18). On 19 March 2018, Axpo Power AG received the restart permit for KKB from ENSI. The NZZ writes: "This decision is especially notable because it does not take into account the political environment, (...) or economic considerations, or security of supply issues, but is based solely on technical analyses and tests. That makes the decision transparent and credible. (...) After a downtime of three years, Beznau 1 can go into overtime as the world's best vetted reactor, and will likely produce electricity for several more years. (...)The decision (...) implies: That the determining factor is not the age of a facility, but solely its condition."

However, a report by the German Ökoinstitut Darmstadt criticises the ENSI decision. In turn, ENSI counters in a statement and insists that most of the safety-technical disadvantages in the report are incorrect or of subordinate importance.

In March 2020, the Swiss Energy Foundation SES  submits a petition  with about 11,600 signatures to the Federal Chancellery of Switzerland calling for the provisional decommissioning of the Beznau 1 nuclear power plant.

Hydropower
Axpo Power AG owns 85 % of Linth-Limmern power plant (KLL) in Linthal and 50 % of the public limited company Kraftwerk Wägital in Vorderthal.

Axpo Power AG owns numerous additional hydropower plants and interests in power plants outside of Northeastern Switzerland. For example the company has an interest in the Ryburg-Schwörstadt hydropower plant (KRS) located on both sides of the border between Germany and Switzerland.

Since the formation of various utilities to become Axpo Holding, Axpo Power AG is now a managing member of Albula-Landwasser Kraftwerke AG in Filisur instead of the former Elektrizitätsgesellschaft Laufenburg EGL, todayy Axpo Solutions AG.

Linth-Limmern
The hydropower plant belonging to Linth-Limmern AG KLL located in the Glarus Alps has been producing power since 1964, and running at full capacity since 1968. The facility includes an arch dam completed in 1963, which holds the 92 million cubic-metres of water in the Limmern lake.

Under the CHF 2.1 billion project "Linthal 2015" the facility was expanded with an underground pumped storage plant. Pumped storage plants are used as "batteries" that store power in the form of water and to stabilise the grid. The expansion increased the installed capacity of the Linth-Limmern power plants by a thousand to 1540 MW. The heart of the plant is housed in a cavern that is larger than the Zurich train station hall. The 1000-metre long gravity dam that now dams the upper basin of the Muttsee is the longest  in Switzerland and the highest-altitude dam in Europe.

The new Limmern pumped storage plant is the largest power batter in Switzerland. If needed, and when the Muttsee is full, the facility can run at full-load operation for 33 hours.

"Achievement of the century" writes the Aargauer Zeitung, that is, however, not profitable. The profitable operation of a pumped storage plant depends on the capital costs and the price difference between the purchased power for pumping and sold peak electricity, as well as utilisation. In turn, this depends on the demand for peak power, which is very low at this time. Axpo Power AG does not expect the plant to be profitable in the upcoming years. The company has created reserves in the millions. The operating period of 80 years for the plant is, however, customary and a long-term one.

Photovoltaics
Large-scale alpine solar plant

Up to now, Axpo Power AG has hardly been present in Swiss photovoltaics although studies like the one carried out by the Federal Office of Energy attest to great potential in Switzerland. Plants in high regions can also generate the needed power in winter.

In 2019, Axpo Power AG announced that the company was planning the first large-scale solar plant in the Alps on the dam wall of the Muttsee (see above). 6000 photovoltaic modules with a surface of 10 000 square metres and a capacity of 2 MW will be mounted to the dam wall. They will produce 2.7 gigawatt-hours of electricity per year to supply about 600 four-person households.

In comparison to a similar plant in the lowlands, it will generate 50 per cent more output. This is because the plant is located over the fog line on a south-facing slope, and the snow reflects the solar radiation. In addition, low temperatures increase module efficiency in contrast to plants in lower regions.

Investment costs for the solar plant amount to CHF 5.5 million with a depreciation horizon of 30 years. Axpo expects a one-off government payment from regular subsidies amounting to CHF 600 000. The plant is primarily intended to alleviate power shortages during the winter. Start of construction is scheduled for the summer of 2021.

Biomass and wood energy
Axpo operates 15 biomass plants, as well as 5 composting sites in Switzerland. The company uses the organic waste from over 2500 customers (cities, towns, industry and commercial enterprises). According to its own statement, Axpo is a leader in the biomass area in Switzerland.

The contribution of biomass to the security of supply in Switzerland is minimal because availability of the raw material is limited. However, biomass contributes to grid stability because power production from biomass is predictable and controllable.

Axpo Power AG operates the largest wood-fired co-generation plant in Switzerland in Domat/Ems.

380-kV line Vorableitung Tavanasa-Breite
Batzberg_-_Dachsegg_2010-06-04_15-14-44.JPG in the Zürcher Oberland (Zurich highlands).

The pylong construction method is typical for Axpo.]] The transmission lines belonging to the Swiss electricity utilities were transferred to Swissgrid on January 2013. Swissgrid is the national grid company and, as the transmission grid owner, now responsible for the safe, reliable, efficient operation of the Swiss high-voltage grid.

Below an excerpt of the transmission lines constructed and maintained by Axpo until 2013:

380-kV line
Up until the transfer to the grid company Swissgrid, Axpo Power AG was the owner of the Vorableitung, the highest altitude high-voltage line in Europe running over the Vorab glacier. It was constructed in the 1950s and 1960s from the Tavanasa switching station to the Grynau substation near Uznach, and from there to the Nürensdorf. The originally planned line layout over the Panix Pass had to be abandoned because of a shooting range. A bolder route was chosen. In some areas 2 lines run parallel, each with a single-level arrangement and span poles for 3 power circuits each.

At the foot of the Kerenzerbergs, the Tavanasa-Breite line crosses over the 380-kV Sils–Fällanden line. Because this line was designed in 1980 for its current voltage level and then increased, an NOK vertical double pole had to be rebuilt into a Donau pole.

Another structural change was made to the line at Grynau at Uznach in 1986. Originally the 380-kV line was built from Grynau to St. Gallen Winkeln. The two transmission lines had the same pylons.

Normally high-voltage lines have to be replaced after 50 years. In the mountains, they are exposed to wind and weather and need to be refurbished after only 25 years.

The Vorableitung is one of five long-distance lines that run parallel to the Biberlichopf and cross over the Linthebene.

380-kV and 220-kV line at Tierfehd-Grynau
Per Ende 2015 wird das neue Pumpspeicherwerk Limmern in Betrieb genommen. Wegen der Leistungssteigerung um 1000 MW auf 1480 MW wurde in zweijähriger Bauarbeit eine neue 380-kV-Leitung erstellt, die parallel zur 220-kV-Leitung den erzeugten Strom Richtung Linthebene transportieren wird. Die Zentrale und das Unterwerk der Kraftwerke Linth-Limmern liegen im Tierfehd, das zur Gemeinde Linthal GL gehört. Von dort aus führt eine 220-kV-Leitung in die Grynau. Dort endet sie in einem der wichtigsten Unterwerke. Zwischen Schwanden GL und dem Kerenzerberg erhielten die NOK beim Bau nur im Hochgebirge Durchleitungsrechte für ihre Fernleitungen. Die 220-kV-Leitung verläuft dort parallel zur Vorableitung und enthält wenige 380-kV-Tonnenmasten. Sie gehört ebenfalls zu den fünf Fernleitungen, die gemeinsam den Biberlichopf flankieren und die Linthebene durchqueren. Sie ist mit fast allen 220-kV-Leitungen der Axpo Power AG baugleich.

The new Limmern pumped storage plant was commissioned at the end of 2015. The increase in capacity from 1000 MW to 1480 MW required the construction of a new 380-kV line parallel to the 220-kV line to transport the generated power in the direction of the Linth plain. The control centre and the substation of the Linth-Limmern power station are located in Tierfehd, which belongs to the town of Linth, Glarus. From there, a 220-kV line leads to Grynau where it ends at one of the most important substations. Between Schwanden, GL and the Kerenzerberg, NOK only received permits to build their overhead lines in the high mountains. The 220-kV line runs parallel to the Vorableitung and includes a few 380-kV vertical double pole. It is one of five long-distance lines that run parallel to the Biberlichopf and crosses over the Linthebene. The construction is the same as nearly all of Axpo's 220-kV lines.

380-kV line Bonaduz–Breite
Axpo Power AG built the 380-kV line at Bonaduz-Breite through the Tamina Valley. The construction is the same as that of the Vorableitung and Elektrizitätsgesellschaft Laufenburg has usage rights for this route.

In Oberterzen the line has two longspan poles with a 2-level arrangement. Apart from these, the line is equipped with vertical double poles.

The Bonaduz-Breite line is one of the five overhead lines running parallel to the Biberlichopf and crossing the Linth plain. From the Schänis industrial zone, it runs toward Nürensdorf on its own route. At Ernetschwil it intersects with the Grynau-St. Gallen Winkeln line and shares a pylon with this line.

380- and 220-kV line in the Rhine Valley
The Rhine Valley line with its two angle tension poles on Liechtenstein territory also belongs to Axpo Power AG. The line was built in the 1970s. Today's 380-kV, 3-pole line starts in Bonaduz and ends in St. Gallen Winkel.

380- and 220-kV-line at Beznau–Tiengen
In the 1960s, the company was awarded a concession to supply German territory. A 380/220-kV line was constructed for this purpose in 1965. Between Beznau and Klingnau the line has 16 vertical double poles. From there the line has a 2-level arrangement; the line was connected with fine distribution from the Klingnau power plant. This north-south connection was labelled Aare-West and Aare-Ost since it largely runs along the Aare River. It crosses the Rhine at Koblenz AG and hence the Swiss/German border, and ends in Tiengen.

220-kV-line at Beznau–Obfelden
In the 1950s, a 220-kV line with intermediate stations was built between Beznau and Obfelden. Construction was relatively easy because the villages had not reached the size they have today. The extension to 380 kV began in the late 1980s using vertical double poles and Donau poles. The project faced opposition from the town of Riniken among others, so that a new line route had to be investigated.

In Obfelden, Axpo operates a joint substation with public utility of the city of Zurich (EWZ), in Thalwil with the utilities of the Canton of Zurich (EKZ).

220- and 380-kV line shared with Alpiq (formerly Aare Tessin AG für Elektrizität ATEL)
The 220-kV line from Laufenburg to Sierentz in the French Alsace no longer exists, but was controversial in the Canton of Basel-Landschaft. In the early 1970s, NOK began with the construction of a new 3807220-kV line from Laufenburg to the Asphard at Kaiseraugst. At the same time, the company built a section of the 380-kV line Asphard-Kühmoos/-Sierentz. One Donau pole and three vertical double poles are located on the Swiss side. It is coupled to the Kühmoos-Sierentz line at Hüsingen. The structure was temporary, until the substation Asphard was built alibg the motorway in the 1980s. Since then, power transport from Laufenburg to Sierentz is ensured by means of this station. The joint line from Laufenburg to the Lachmatt at Pratteln belongs to Axpo Power AG up to the hillside at Möhlin, later it belongs to ATEL Netz AG. Half of the line has 220 kV and includes a substation at Münchwilen AG. A 3-pole 380-kV line feeds the Asphard substation with electric energy from the Gösgen nuclear power plant.

Fine distribution at Münchwilen–KRS
A 3-pole fine distribution leads from the Riburg-Schwörstadt power plant to Münchwilen AG. The line was built in the 1930s. Today, it shares most of its pylons with the previously mentioned joint line. All the pylons of this long span are labelled "Mü-KRS".

Also see

 * List of the substations in Switzerland's high-voltage grid

Web links
Commons: Axpo - selection of images, videos and audio files


 * Axpo Power AG web presence