Local news Czechia

December 2021: Årlifoss and Grønvollfoss, Norway – Large automation rehabilitation order 

One of the larger ANDRITZ Hydro automation orders globally within service and rehabilitation in 2020 is now well into the execution phase. 


Årlifoss and Grønvollfoss are two Norwegian run-of-river hydropower plants located within 5 km on the same river, and 125 km west of Oslo. They are owned and operated by Skagerak Kraft - a utility company with about 4% of total electricity output in Norway.

The rehabilitations are carried out jointly as one project with final take-over by the customer in the end of 2024. The project is an excellent example of collaboration across ANDRITZ locations. Project management, system engineering, design, and site supervision are all done by the ANDRITZ team in Jevnaker, Norway, while colleagues in the Czech Republic are responsible for programming, automation FAT and commissioning.

The first phases of Årlifoss with control of head water level, spillway gates and common functions will already be commissioned and taken over by Skagerak by December of this year, says Project Manager Øyvind Kristiansen. Start-up for Grønvollfoss engineering is in November, he adds.

In the Norwegian hydro market customers typically have common contracts for control and Electric Power Systems (EPS) systems in greenfield and refurbishment projects. At ANDRITZ Norway sales and project execution teams are organized to operate in this common Automation and EPS market. Control and protection system with turbine governor, control of spillway gates, redundant level control, AC and DC station supply, several Medium voltage switchgears for generator-grid coupling and station supply are all in the scope of delivery to both power plants.

The new control systems are designed to meet the requirements of the EU Machinery Directive for the turbine-generator-transformer system. Critical functions like PLC’s and monitoring of bearing temperatures, runaway speed, and synchronization are also duplicated in autonomous units, which is standard for this generator size.

Both power plants are equipped with Kaplan turbines, providing reliable and clean energy to 15,000 homes. Årlifoss came into operation already in 1915 and has since then undertaken several upgrades. Today, the plant has one 26 MW generator and a head of 16 meters.
Grønvollfoss was originally built in 1933 and has currently two generators at a total installed capacity of 32 MW and 23 meters head. 
Skagerak has awarded ANDRITZ a second contract for the mechanical upgrade at Årlifoss with replacement of rotor and other generator upgrades, a new ANDRITZ Kaplan turbine, and new high-pressure oil unit for the turbine governor.

In accordance with the ISO 14001 certification of the ANDRITZ Group and the environmental emphasis by the customer, there is a focus on short transportation and regional production in Norway. The switchgear will be supplied with environmentally friendly breaker medium.

We are grateful that Skagerak Kraft has awarded this important contract to ANDRITZ and are looking forward to a successful completion of the project.

Technical Details:

Total output:26 MW
Scope: 1 x 26 MW
Head: 16 m
Voltage:9.5 kV
Speed: 136.4 rpm
Runner diameter: 4,500 mm

Total output:64 MW
Scope: 2 x 32 MW
Head: 23 m
Voltage: 8.0 kV
Speed: 200 rpm
Runner diameter: 3,120 mm

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