BoM sends hefty fees to offshore wind project developers to test impact on its weather forecasts

It’s not just Gippsland communities which are being overwhelmed by requests from offshore wind developers, it turns out that the Bureau of Meteorology (BoM) is too. But it’s turned the influx of work into lemonade, so to speak, for which it’s charging $45,000 a pop.

The BoM is concerned about its ability to forecast weather coming in over the Bass Strait through a wall of large wind turbines proposed for Australia’s first offshore wind zone off the coast of Gippsland in Victoria.

Wind turbines are said to play havoc with weather radars, which locate rain and other precipitation by bouncing electromagnetic pulses off the particles and reading the ‘echoes’.

But the number and complexity of the now 11 remaining projects off the coast of Gippsland has prompted the agency to streamline the developer information gathering process. 

Following “consistent and increasing demand from proponents”, the BoM has set up a process just for offshore wind developers to conduct a deep dive into the potential impacts of their projects, and the mitigation options. The cost to each is $45,000, and is being described by the BoM as cost recovery.

“Proponents generally consult by, on their own initiative, sending to the Bureau details of their development, such as the size, number and location of wind turbines and related infrastructure,” a BoM spokesperson said in a statement to Renew Economy.

The BoM does a quick, free assessment to see if a project will disrupt its high resolution doppler radars, particularly those at Bairnsdale in Victoria and Takone in north-west Tasmania. 

And, if it looks like it will potentially disrupt the radars, proponents can seek advice elsewhere, or do a deep dive with the BoM. 

Australia’s weather radar map. Image: BoM

No one expects all 11 projects worth 23 gigawatts (GW) to survive to operation given Victoria’s offshore wind target tops out at 9GW in 2040. 

Some of the lesser equipped players have already withdrawn. Bluefloat Energy was the first to go, scrapping not just the Gippsland project but its entire global offshore wind division last week. It had yet to start construction of a single project anywhere in the world.

The BoM’s system is proving useful says Charles Rattray, CEO of the first Gippsland offshore wind project proposal Star of the South, which is widely expected to be the first one actually built.

“Star of the South has a collaborative relationship with BoM,” he told Renew Economy. 

“They’ve put a clear process in place for working with offshore wind projects which gives us clarity and will make things work well.”

Fixing the problem

The main problem is the impact of the wind farms on the electromagnetic spectrum the BoM’s radars use to track weather systems, the spokesperson says.

“Wind turbines can affect the electromagnetic spectrum in which weather radars operate. The effects on radar function can include the apparent detection of rainfall when there is actually no rainfall or the inability to detect rainfall where it is actually occurring,” the spokesperson says.

On its South Australia information page, the BoM says its radars sometimes read the echoes of moving turbine blades at the wind farms near Edithburgh on Yorke Peninsula, Snowtown and Waterloo to the north, and Cape Jervis on the Fleurieu Peninsula as stationary rain clouds. 

The Murra Warra wind farm and turbines near Lake George in New South Wales (NSW) have both been accused of confusing weather radars in the past. 

Given the Gippsland zone is not moving, developers and the BoM will need to find ways to mitigate the effects of the proposed wind farms.

The BoM says what’s done depends on how badly radars are affected. 

“They often include the installation of rain gauges or automatic weather stations to provide reliable measurement of key weather parameters in the areas likely to be affected by wind turbine installation,” the spokesperson says. 

But these measures may not be as useful offshore as onshore. 

A study from 2022 noted that where the turbines are placed can help, as can adding “stealth radar-absorbent material” to blades which can lessen the impact, the study suggests, by up to 99 per cent. 

The expensive, for the BoM, option is to replace the radars.

The study put the cost in 2022 at $US3-8 million ($A4.6-12 million, today) to replace one radar.

But the BoM says the cost over time is much, much higher: installing and running one radar over a scheduled 20-year life span is about $35 million.