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Sigalda Power Station Expansion

The expansion of Sigalda Power Station includes a new generating unit, penstock, and widened tailrace canal, increasing the station’s installed capacity from 150 MW to 215 MW.

Sigalda Expansion Project

The original design of Sigalda Power Station envisaged for a future expansion, and this was taken into account in the construction of the powerhouse and intake. The expansion involves an extension to the southwest of the existing powerhouse, including a fourth generating unit and a new penstock. In addition, the tailrace canal near the station will be widened. Once completed, the installed capacity of Sigalda Power Station will increase from 150 MW to 215 MW.

The objective of the project is to increase flexible capacity and enhance the regulation and responsiveness of the power system, while improving efficiency without the need for new reservoirs. Most permits for the project have already been secured, with only the construction permit for the expansion remaining.

  • The project is scheduled for completion in autumn 2029.

  • Installed capacity

    0MW

    increase from 150 to 215 MW

  • Rated discharge

    0m3/s

    increase from 240 to 350 m3/s

Project Status

Preparatory work of various kinds began in March 2025, followed by the construction of water supply for the construction camp. The workforce on site is expected to average around 110 people, including Landsvirkjun staff and contractors, peaking at approximately 140.

Due to the expansion works, power generation will be suspended for two months in July and August 2026. A further suspension of around four months is planned for summer 2028, although exact dates have not yet been determined. The Krókslón Reservoir will be emptied both times and the flow diverted through the Sigalda Canyon.

Various preparatory activities have been carried out throughout 2025, including site preparation for construction facilities, installation of electricity and lighting, erection of a telecommunications mast, signage, and more. Construction of the Sigalda Power Station expansion began in autumn 2025 with excavation for the powerhouse extension.

  • All major construction activities are expected to begin in summer 2026.

How will the area change?

Here you can see how the power station area will look before and after construction. Drag the slider left and right to see the change.

BeforeAfter
BeforeAfter

Q&A

  • A fourth generating unit will be added to the existing hydropower plant, along with a new penstock and an extension to the powerhouse. The tailrace canal near the station will be widened.

  • It will increase the capacity and responsiveness of the power system, support peak demand, and strengthen security of supply without creating new reservoirs.

  • Installed capacity will increase from 150 MW to approximately 215 MW. Rated discharge will increase from around 240 m³/s to around 340 m³/s.

  • Yes, slightly due to improved efficiency. However, the main benefit is increased flexible capacity and overall system stability.

  • Water levels and fluctuations in Krókslón reservoir will remain similar to current conditions. Variations will be balanced further downstream in the system.

  • Construction is expected to take approximately 3-3,5 years.

    Two temporary shutdowns are required for 2-months in 2026 and for 4-months in 2028. During these periods, water will be diverted through the bottom outlet and the Sigalda Canyon, similar to major maintenance operations.

  • Impacts on landscape and aquatic life are assessed as negligible, with mitigation measures and regular monitoring in place. Disturbance from material extraction will be localized to previously disturbed areas, which will be restored after construction.

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About Sigalda Power Station

Sigalda Power Station was commissioned in 1978. It is a 150 MW hydropower plant with an annual generation capacity of 930 GWh. The station utilizes Krókslón reservoir as its intake and operates with a total head of approximately 72 metres. Discharge flows through a channel into Hrauneyjalón reservoir. The powerhouse houses three 50 MW generating units.

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