420 kV Ofoten – Balsfjord420 kV Ofoten – Balsfjord

EFLA worked with Statnett from the preparation stage, by assisting with the choice of the line route and making geotechnical estimates for foundation design. In the 160 km 420 kV OHTL from Ofoten to Balsfjord, Statnett decided to use standard Statnett steel portal towers and foundations. EFLA designed all the towers and foundations, and assisted with project and site management. For the design of the towers and the foundations, EFLA used specialized Excel Macros along with PLS-Cadd/Tower.

The transmission line will eliminate a bottleneck in the main grid between Nordland and Troms counties. It is necessary due to an expected increase in consumption and for greater industrial activity in Northern Norway. The OHTL is a precondition for optimal function of the Balsfjord-Skaidi line, which continues onwards to the north.

One of the challenges in the project were the long transport and difficult access to the line route, where transport of people and material was mostly done by helicopters. Due to the short days and limited daylight during the winter months, the need for good planning and effective construction management was essential.

Statnett was responsible for the choice of the line route, environmental studies, building permits and the environmental, transport and construction plan (ETC-plan), where facilities for employees and storage are listed, along with the location for preassembly sites, storage for drums and stringing equipment.

Construction and access roads, access for helicopter for material and workers are also stated in the ETC-plan. Permanent environmental impact due to construction of the line was minimalized as much as possible. Reindeer farming on the line route was respected, by having restriction periods during parts of the year.

• Implement the line route and investigate geological and geotechnical conditions
• Preparation before construction, construction management and technical supervision
• Structural design of all towers and foundations as well as assistance with tower spotting
• Structural design of changes on other OHTL this line affects
• Consultation and assistance regarding supply of material and construction

Strengthening of the main grid to improve the security of supply in northern Norway, promote industrial growth and increase value creation. In an addition, the project is a premise for future production of renewable energy in the area.