Growing scientific concern over the potential impact of large offshore wind farms on regional rainfall patterns has prompted calls for more comprehensive research before such projects proceed in Australia, starting with the $8 billion Star of the South development off Gippsland, Victoria.
A recent German government-funded study published in Communications, Earth and Environment highlights that offshore wind farms in the North Sea could reduce precipitation by 10 to 12 percent across parts of Germany, the Netherlands, and the United Kingdom. The research, led by Dr. Naveed Akhtar of the Helmholtz-Zentrum Hereon institute, suggests large-scale offshore turbine arrays significantly alter local and regional climate by changing sea surface heat and momentum fluxes. This leads to increased cloud cover and precipitation over the wind farms themselves while reducing rainfall downwind, with turbine wake effects potentially extending 50 to 70 kilometers.
In Australia, Ivan Kennedy, Professor Emeritus at the University of Sydney specializing in Agriculture and Environmental Chemistry, is conducting his own research into turbine wake effects and their potential implications. Kennedy expressed particular concern about the Star of the South project’s 147 proposed turbines, located approximately 10 kilometers offshore from Gippsland’s coast. He warned that reduced rainfall and drying in areas downwind, including the Ramsar-listed wetlands of Corner Inlet and surrounding agricultural lands, could lower plant productivity and exacerbate bushfire risks in a region already vulnerable to drought and fire.
“The drying out of the landscape jeopardizes productivity and makes bushfire management more difficult,” Kennedy said, highlighting that wake effects observed in Europe could affect vast areas inland. He also voiced similar concerns about proposed offshore wind farms near the Illawarra coast in New South Wales, which he suggests may shift rainfall patterns offshore and reduce water availability in hinterland catchments.
Local community groups advocating for more stringent evaluation echoed these concerns. Alex O’Brien of Responsible Future Illawarra raised the possibility that large-scale wind projects might unintentionally increase bushfire vulnerability by decreasing rainfall and humidity. Brad Anderson, co-convener of Gippsland’s No Offshore Turbines 90 Mile Beach group, called for nationwide investigations into these impacts to better understand the risks.
The Star of the South project, supported by Copenhagen Infrastructure Partners, maintains that turbine wake effects were thoroughly assessed during its environmental impact process and deemed negligible. Chief Executive Charles Rattray emphasized the project's turbines would be sited at least 11 kilometers offshore, where wake effects on coastal rainfall and land conditions would be minimal. Rattray further stated that global experience with over 15,000 operating offshore turbines provides a substantial knowledge base that supports this conclusion. He also underscored the project’s economic benefits and its role in mitigating climate change impacts, which are a more direct threat to regional dryness and fire risk.
Federal Environment Minister Murray Watt and Energy Minister Chris Bowen declined to comment, while a spokesperson for the national Environment Protection Agency affirmed that all relevant scientific evidence and public submissions are considered in the project's federal assessment process.
As offshore wind development accelerates worldwide, these emerging studies underline a need for further investigation into how large wind farms might influence atmospheric and hydrological conditions onshore. The German research team concluded that extensive offshore wind deployment “may significantly alter regional climate patterns,” pointing to a gap in current understanding that Australia faces as it advances its own offshore wind industry.