How safe are those transmission towers?

Australia – and in particular regional Australia – is looking at an additional 10,000km or more of power lines to carry the load of our future renewable energy network.

The Australian Energy Market Operator (AEMO) has just released its 2023 Electricity Statement of Opportunities (ESOO) report, a 10-year reliability outlook that says there are “significant risks to reliability” without new and sustained investment.

It has already said in its Integrated System Plan that Australia needs 9 times the large-scale renewable generation we have now and massive tracts of new transmission lines.

But transmission lines and towers need to go somewhere, and in many cases, that is on private property along the lengthy routes connecting new renewable energy projects to the grid.

People across regional Australia are receiving more frequent notifications that their property has been earmarked for infrastructure for different projects.

Some landowners have protested the loss of agricultural land and productivity, increased fire risk, devaluation of their properties, and damage to local ecosystems.

Another concern is uncertainty about the safety of living within close proximity of 500 kilovolt transmission lines.

Debate has raged for many years about a connection between childhood leukaemia and the proximity to power lines. A 2018 international pooled analysis into the issue found “a small and imprecise risk for residences less than 50m from 200+ kV lines that was not explained by high magnetic fields”.

Jacqui Gidley-Baird, who owns a farming property in Dungowan in the New England region of New South Wales, is one of a number of farmers who have recently discovered their property has been earmarked for transmission towers as part of the New England REZ Transmission Link.

In the Gidley-Baird’s case, they are looking at two 500kV towers – high-voltage lines that are usually resting on towers 50 ­­- 80m tall.

Gidley-Baird says the concerns about these towers are “endless” – chiefly fire and loss of productivity – but health remains a worry, both for themselves and their animals.

“I don’t have clarity on how close the towers are to my house,” she says. “All that you get from the government is we are going to acquire this kilometre-wide corridor and there will be towers and lines somewhere on there.

“It could be half a kilometre, but I do have neighbours where it is the whole width of their block, so it will go within 100m of their house.”

Associate Professor Ken Karipidis from the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) – the federal government’s peak body on radiation protection and nuclear safety – says anything electrical carries a current and emits electric and magnetic fields.

The most extreme impact of electric and magnetic fields is electrocution.

“But what has been suggested,” Karipidis says, “is that electric and magnetic fields from power lines can have long-term effects, such as cancer. Now that hasn’t been proven, but that is the suggestion.”

Karipidis says the question of power lines and human health has been around since the 1970s, and while the greater the voltage, the greater the exposure to electric and magnetic fields, the exposure rate drops away rapidly. “Living 100m from a power line is likely to create no greater exposure than if the power line was not there at all,” Karipidis told Cosmos. 

But what are the risks if there are 2 parallel transmission towers, as is likely to be the case on the Gidley-Baird property?

According to Karipidis, 2 towers could be better than 1.

“Having 2 lines side-by-side will not necessarily increase the exposure and will probably decrease it,” he says. “With power lines, you usually have quite a number of lines, and the reason for that is you have electrical current going one way, and you have electrical current going the other way.

“The more lines you have, the more the electric and magnetic fields cancel each other out. So having 2 lines will likely decrease the exposure.”