Vandkraft

Qorlortor­suaq vandkraft

Greenland

Verkís scope of services encompassed feasibility study and site evaluation; EPC bid preparation; Tender design for subcontractors; final design of all civil work; Detail design and/design review of all electrical and mechanical equipment; Site acceptance and commissioning.

Sizes: installed capacity 2x 3,8 MW, rated discharge 2x4,2 m3/s
 Project time:  2003 - 2007

Project overview:
The Qorlortorsuaq hydropower plant provides the nearby towns Qaqortoq and Narsaq, with a combined population of 5.500, with electricity. The energy production of the two power units is 27,5 GWh/a. The design period started in 2003 and finished with commissioning in 2007. The hydropower plant has replaced diesel generators which used to provide the two towns with electricity.

The government of Greenland aims to replace fossil fuelled power plants with renewable energy. The focus has been on hydropower and the Qorlortorsuaq hydroelectric project is an important piece in a number of planned hydroelectric projects.

Qorlortorsuaq Hydroelectric Project, situated in South Greenland, is a joint venture total contract by Pihl & Søn, Ístak, Yit and Landsvirkjun. All the design and engineering, except the transmission line, was performed by Verkís. The hydropower plant supplies the towns Qaqortoq and Narsaq with electricity.

The plant harnesses water from natural lake with an average inflow of 3,9 m3/s. A concrete dam, 8 m high and 900 m long, raises the lake´s water level from 120,5 to 128 m a.s.l. The water is conveyed from the intake through a 225 m long tunnel and a 350 m long steel penstock before entering the two 3,8 MW Francis turbines on a horizontal axis in a surface powerhouse. Each turbine has a rated discharge of 4,2 m3/s. The 6,3 kV voltage produced by the generators is transformed to 63 kV in the station's transformers. A 70 km long transmission line delivers the electric power through a switchyard at Tartoq and to the two substations located in each town. The Qaqortoq substation transforms the 63 kV to 10,5 kV and delivers it to another previously existing substation. The Narsaq substation transforms the 63 kV to 6,3 kV with two outgoing 6,3 kV feeders.

The powerhouse is equipped with a bridge crane, backup diesel generator, machine shop, control room, cooking facility and sleeping area for four people. The tunnel was excavated beneath the lake and exploded up through the bottom, deep under the surface of the lake. In the middle of the tunnel there is a concrete plug and a sliding gate. A special cross gate makes the inspection and maintenance of the sliding gate possible.

The Qorlortosuaq Hydroelectric Project was Verkís' first hydroelectric project in Greenland following the realisation of the Sisimiut hydroelectric project.