300 km north of the Norwegian capital Oslo, at the river Smådøla, a new small-scale hydropower station is being constructed, which will provide 12,000 households with clean energy.

The project is implemented and supervised by by the Siemens Competence Centre for Small Hydro in Salzburg. The contract includes the supply and installation of all power plant components, from the turbine to the grid (“water-to-wire” package). The contract was awarded by Norwegian power plant and network operator A S Eidefoss. For Siemens, this project marks the entry into the Norwegian small-scale hydropower market.  The hydropower plant is designed as an underground facility, with water being supplied by way of a pressure tunnel. This means that the Smådøla is left to flow undisturbed above ground while contributing to power generation “down below”. Three turbines of different capacity are to be efficiency optimised to generate a total of 15.21 MW, depending on the available volume of water. The plant is scheduled to be commissioned in 2015. Siemens was awarded the contract by Norwegian energy provider A/S Eidefoss. The order includes the supply of the entire mechanical, electrical and building technology for the water intake, the power house as well as a service building in front of it – i. e., a complete “water-to-wire” package. “We decided in favour of Siemens for this project, as their offer was technically convincing and met all our tender requirements perfectly. Siemens is a reliable partner in terms of investment protection, which was crucial in this project,” says Jan Harald Bakke, Project Leader at Eidefoss.

Flexibility during the planning phase
During the planning stage of the project, Siemens provided the customer with advice on the electrotechnical design and component optimisation. The flexible service and know-how provided by Siemens, combined with the use of the latest planning tools, allowed for changes to be integrated quickly into the project plan without causing any delays. For example, a grid analysis was performed in advance to determine the influence of the current feed on the voltage behaviour within the grid. Siemens also worked in close cooperation with the civil engineers to optimise the power plant layout and accessibility of the equipment with the indoor crane, and to prepare the required working areas and transport paths. A special challenge was posed by the distributed locations of the various high-volume power consumers, such as the ventilation units that supply fresh air to the tunnel and cavern. This made it necessary to install an additional grid level for energy transfer, including step-up and step-down transformers. Thanks to their experience, the Siemens engineers confidently mastered such tasks as connecting the power station to the grid at the Eidefoss control centre some 20 km away, or calculating an optimum switching matrix between the machines depending on the available water volume.

The challenge: installation and start-up
Creating local value is important to Siemens, which is why local firms were subcontracted for instillation work wherever possible. With “hands-on mentality”, Siemens foremen supervised the installation work, lending a helping hand where necessary. Due to the very limited space in the cavern and access tunnel, transporting the equipment to the installation side and storing it without obstructing other components posed a logistic challenge.  With the construction site located in the Norwegian mountains, the installation work was accompanied by changing environmental conditions all year round. As a result, the Siemens team was constantly faced with challenges such as road damage due to heavy rain, or extreme snow conditions. However, careful pre-planning of transports and the excellent cooperation with Eidefoss allowed them to compensate for these influencing factors. In the end, the start-up went ahead in the winter, as planned. In the intake area, the Siemens engineers were faced with temperatures as low as -25 °C, wind speeds of up to 100 km/h and snowdrifts more than a metre high. Among other things, these conditions led to the intake gates icing over. But thanks to the dedicated personal effort of everyone in the Siemens team and local firms specialising in de-icing, this problem was eventually solved as well. Finally, the start-up process could be completed according to schedule.

Concentrated hydropower competence in Salzburg
Siemens Austria’s Small Hydropower Competence Centre in Salzburg is the global hub for the group’s worldwide small-hydropower business. With a product range covering everything from turbines to transmission lines, Siemens stands out as a single-source provider of all components for small hydropower stations. The portfolio includes everything from planning to engineering, delivery, installation and start-up of facilities up to 30 MW. Mechanical power station components such as turbines and generators are combined with electrical and control technology systems. So far, the Competence Centre for Small Hydropower in Salzburg has completed more than 400 projects worldwide. In addition to the alpine region, projects were implemented in southeastern Europe – Greece and Turkey, for example – and in Scandinavia.