Reservoir filling commenced late 2006, almost on programme despite foundation difficulties at the Halston site to work taking place concreting works on the CFRD slab through an Arctic winter. By the end of last month the reservoir was almost full.
Construction of the Kárahnjúkar project started in early 2003 and all units were to go into operation by last month. The project has, at 200m, Europe’s highest concrete faced rock fill dam and a 40km main headrace tunnel, mostly unlined, with 20km of branch tunnels. The gross head is 600m and the powerhouse is fitted with 115MW high head Francis turbines.
Difficult geology was also experienced in driving the headrace tunnel. To enable the start-up of the first units near schedule the impoundment operation also enabled Landsvirkjun to fill part of the headrace tunnel network, not including the branch tube. Tunnelling work is still continuing to drive the Jokulsa branch tunnel.
Kárahnjúkar’s public relations director, Sigurdur Arnalds has said that the machines in the plant are being tested and the turbines will go online one by one until the plant is running at full capacity. The plant should be at full capacity within a few months.
All construction work on the project should be completed by late 2008 following completion of the works at the second catchment and diversion area.
