Bunnythorpe to Tokaanu upgrade subproject
Our project to increase the capacity of our two lines between Bunnythorpe and Tokaanu involves operating the lines at a higher temperature – what we call a ‘thermal upgrade’. This subproject will get underway from about the end of 2025.
What is a ‘thermal upgrade’?
When we run our transmission lines hotter, they can carry more electricity but the wires will sag more (steel expands when heated) bringing them closer to ground. In some cases the wires will be too close to the ground, and we will need to do work to increase the distance between the ground and the wires. This can be done by work on the towers to make them taller, adjusting how the wires are held at the tower, or earthworks on the land underneath. Alongside this, we may also need to strengthen the towers by reinforcing them with extra steel, or strengthening their foundations with concrete. You can read about the types of work we have to do to on these lines to increase their height.