Maintaining a hydro presence3 November 2011
Swedish power producer Vattenfall has numerous hydropower operations in Europe. Here, IWP&DC presents details on refurbishment work being carried out at the Akkats power plant in Sweden, together with information on the Olidan power project
Vattenfall is the third largest hyro power producer in Europe, with hydro accounting for roughly 20% of the company’s total electricity generation. It was in 1909 that the company launched its first hydropower facility in Sweden with the Olidan power plant on the Göta river in Trollhättan, followed by the Porjus power plant in Lappland in 1915. Today, Vattenfall is an international energy company with 40,000 employees in eight countries. Its core markets are Sweden, Germany and the Netherlands. Vattenfall is fully owned by the Swedish state.
Electricity generated by hydropower has been a cornerstone in the construction of modern-day Sweden. The development of Swedish rivers took place quickly and the most intense period was between the 1940s and 1960s. However today, it is not possible to build new hydro power plants in Sweden. All rivers are developed with the exception of four so-called national rivers which are protected by law against any development.
Many existing power plants are also coming of age, and Vattenfall is refurbishing its plants in Europe on a continual basis. Up until 2023, SEK 7.7B (US$1.2B) is to be invested, primarily to replace turbines and generators. A comprehensive dam safety programme worth nearly SEK 3B (US$0.5B) has been underway since 2002, with completion scheduled for 2014. The dams are to be strengthened for future climate change with its anticipated higher water flows.
Akkats power plant
In Sweden, hydropower generation is enhanced by investments in existing power plants. Through these investments the replacement of mechanical equipment is set to provide an additional 0.45TWh of energy by 2023. One of the biggest ongoing projects is the rebuilding of the Akkats power plant in Jokkmokk, northern Sweden - an investment worth SEK1B (US$0.16B).
Located on the Lule Älv River, Akkats was inaugurated in 1974 and fitted with a 150MW turbine unit. In the spring of 2002 an incident occurred during refurbishment of the equipment which controls and turns the guide vanes. After start up and stopping tests, it was during a load rejection when one or more links between the rotary actuators and the guide vanes were released and closed more rapidly than intended. The rapid closure created a vapour bubble that covered the Kaplan runner, resulting in a column separation. A few seconds later the vapour bubble collapsed and created a large lifting force on the runner with 700 tonnes of shaft and generator rotor. Ultimately the whole three-floor building moved by several millimeters, resulting in damage to the structure.
Although extensive repairs were made, it only proved possible to regain 80% of the plant’s original generation capacity. To increase this, Vattenfall took the first step in 2008 to restore the facility and build two new units (75MW each), replacing the older 150MW unit.
The majority of the construction work will be performed below ground level. Environmental aspects are of major importance during the development of the new units: among other things, old materials are to be reused and new technology will make it possible to use up to 70% less lubricating oil. Construction is expected to be finished in 2014, increasing the capacity of the station by 26GW/yr, which is enough to meet the needs of roughly 1200 households.
To date a new inlet tunnel and a new suction pipe have been built. The first 75 MW unit was installed and the original unit is now being removed to be replaced by the second 75MW unit in 2012.
The Lule Älv River, on which the Akkats plant is located, is Vattenfall’s and Sweden’s most important river for hydro power generation. In 2008 it was responsible for 13.8TWh, or almost 10%, of Sweden’s overall demand during a typical year.
Vattenfall Hydro Power
Vattenfall Hydro Power AB currently has operations in three countries: Sweden, Finland and Germany. In Sweden, there are 53 major power plants (more than 10MW) and 39 smaller facilities (0-10MW), in Finland there are ten small power plants and in Germany three small power plants and eight pumped storage power plants. The installed capacity totals 11,500MW with an annual production of 33.5TWh.
Vattenfall also set up operations in France a couple of years ago to be able to participate in the bidding process for a total of 5300MW of hydropower which has been out put on tender by the French government until 2015.
|Akkats hydro plant|
Installed electricity capacity: 150MW
|Olidan hydro plant|
Installed electricity capacity: 77MW