Transmission Line Construction in Sub-Arctic Alaska Case Study: "Golden Valley Electric Association's 230kV Northern Intertie"

Construction projects throughout the world have become more complicated and logistically challenging as environmental stipulations become more demanding and the effects climate change become more pronounced. No where is this more evident than in the sub-arctic, in this case interior Alaska, where Golden Valley Electric Association, Inc. (GVEA) is the Owner of the recently constructed 230 kV Northern Intertie transmission line project. This transmission line project is underlain by "warm" discontinuous permafrost prevalent throughout interior Alaska. The potential for change in the marginal permafrost over the life of this project had to be addressed at the design phase to provide the most economical project. This case study discusses the challenge engineers and contractors alike faced in scheduling, accessing and constructing a project across four distinct geographic areas, with an emphasis on permafrost zones. Contractors faced extreme weather conditions where summer sun shown for as much as 21 hours, to winter conditions with as little as 3 hours of daylight. Temperatures during construction varied between 32°C (90° F) and –45° C (–50° F). Without a clear understanding of design parameters between the Engineer and Contractor, projects can easily become problematic.