Trees are the number one cause of unplanned power outages across Tairāwhiti and Wairoa, and right across New Zealand. During a storm, trees and branches that touch or fall through power lines cause widespread cuts to the electricity supply. And, they often require expensive and extensive repairs.
Eastland Network has partnered with forestry company Grandy Lake Forest (NZ) and their management consultants, Merrill & Ring, on a long-term solution – one that will protect the lines, minimise power outages and the risk of fire, improve worker safety and deliver significant advantages at harvest time.
“As the lines company for Gisborne, Wairoa and the East Coast, we cover nearly 12,000 square kilometres of mainly rural land, which includes many large areas of forest,” says Eastland Network general manager Brent Stewart.
“Under current regulations, all landowners must keep trees away from power lines. But the reality is that pine trees can grow to 40 metres in height, and in bad weather they regularly damage lines. So, we’ve worked with Merrill & Ring at Grandy Lake’s Ikanui Forest to create the region’s first ever 80-metre wide corridors.”
There are two separate corridors, extending a total of four kilometres. The before and after photos are dramatic.
Eastland Network Project Manager Earl Walker regularly talks to forestry companies about considering widening corridors after harvest, before the replanting takes place. He says that Merrill & Ring Forest Manager Graham Douglas suggested teaming up on the initiative.
“This 33kV line is a main sub-transmission line which supplies multiple 11kV feeders,” explains Mr Walker.
“It’s in a high wind zone through the forest and the original corridor, at a standard 40-metres wide, made it vulnerable to bad weather. If a pine tree took this line down, a major outage would occur, with all of Mahia, Nuhaka, Tahenui and Morere (1,700 connections) losing power.
“With the new corridors in place, this risk to the local communities has been minimised. Merrill & Ring not only appreciate the benefits, they proactively approached us to work together on a solution.”
Mr Douglas says that more than 1,500 seven-year-old pine trees were felled to create the corridors. He believes that it was a short-term investment that will more than pay for itself over time.
“Our forestry management company, and Grandy Lake Forest, have a long-term view of forestry. For us, it’s a matter of taking a responsible approach and considering everyone who could be affected. We believe that creating effective buffers like this benefit absolutely everyone, from the forestry owners to the lines companies and the surrounding communities.
“With easy access well away from the power lines, the costs and challenges at harvest time will be significantly reduced. Compliance, risk management, and health and safety will all be improved. The power won’t need to be turned off for harvesting, and it will be a safer environment for our workers.”
The project to widen the corridors began in late September, and has recently been completed.
“We’d like to publicly acknowledge Merrill & Ring and Grandy Lake Forest for their foresight,” adds Mr Stewart.
“We hope that the demonstrable advantages for lines companies and forestry companies alike – not to mention the workers and local communities – will see these 80-metre wide buffers become the norm, not the rare exception.”
Before and after: More than 1,500 trees cut down to create 80-metre wide buffer for important 33kV line near Wairoa.