The Federal Government has declared Australia’s first offshore wind zone, which gives wind farm developers the go-ahead to ramp up their planning and consultation for projects in this designated area.

But what are offshore wind zones, and why is Australia’s decision to embrace them significant? Here’s what you need to know about offshore wind farms and the role they can play in the evolution of Australia’s energy system.

What is offshore wind energy?

Offshore wind energy is renewable energy that’s generated through the force of the winds out at sea. Wind currents are converted into electricity using wind turbines, which are grouped together in wind farms just as they are onshore. Subsea cables transfer that electricity from the wind farm to the shore, so it can be supplied into the electricity grid to power homes and businesses.

The advantage of going offshore is that small increases in wind speed yield large increases in energy production, and wind is generally stronger and more consistent at sea than on land. This means turbines can produce more energy, more often, helping to provide a steady supply of power to the grid at times when solar power and onshore wind are not available.

The disadvantage is that offshore wind farms are generally more expensive and difficult to install and maintain.

There are two primary types of offshore wind farms – fixed foundation, in which the turbines are secured directly to the seabed, or floating, in which the turbines are mounted on a floating foundation that’s secured to the seabed by anchored cables.

Up until now, commercial wind farms have been almost exclusively fixed foundation, and limited to water depths of up to 50-60 metres. Recently, however, floating wind turbines that can be installed at greater depths have begun to be commercialised.

Offshore wind power is currently scaling up across the UK, Europe and Asia-Pacific, and in 2019, the International Energy Agency (IEA) identified offshore wind energy as one of the ‘big three’ sources of energy, alongside onshore wind and solar PV, that are expected to power the global shift towards renewables.

What’s the status of offshore wind energy in Australia?

Onshore wind generation is Australia’s largest clean energy technology, accounting for 11.7 per cent of total generation and 35.9 per cent of renewable generation in 2021.

Australia added 1746 megawatts (MW) of onshore wind capacity in 2021 – the third year in a row that the record for new capacity has been broken – and plans were recently announced for one of the world’s biggest onshore wind farm precincts to be connected to the grid in Queensland.

But offshore, it’s a different story. Australia currently has no offshore wind generation, despite having almost 60,000 kilometres of coastline and no shortage of wind resources.

In July 2021, the Blue Economy Cooperative Research Centre’s Offshore Wind Energy in Australia report – a collaboration between CSIRO, the University of Technology Sydney’s Institute for Sustainable Futures, Saitec Offshore and the Maritime Union of Australia – noted that the conventional wisdom in Australia has been that offshore wind energy doesn’t have a role to play in our electricity system.

This is because Australia is rich in sites that are well-suited to onshore wind and solar generation, and doesn’t have the land space constraints of some other nations. The shelf also falls away quickly across much of the coastline, leading to water depths that make fixed foundation turbines unfeasible.

However, the report noted that the global development of floating turbines is changing this perception. The report also advocated for the potential of offshore wind turbines to diversify the supply of energy to a grid that has become increasingly reliant on intermittent onshore wind and solar, and provide future employment for workers in the coal, gas and oil sectors.

In September 2021, the former Federal Government tabled legislation that would enable offshore wind projects to be built in Commonwealth waters.

And in August 2022, the current Federal Government designated waters off the Gippsland coast, in Victoria’s south-east, as Australia’s first offshore wind zone, giving developers permission to increase their planning and consultation for wind farm projects within that zone.

The government has also identified another five regions with “world-class” offshore wind energy potential that will be prioritised for development, including the Pacific Ocean regions off the Hunter and Illawarra in New South Wales; the Southern Ocean region off Portland in Victoria; the Bass Strait region off northern Tasmania; and the Indian Ocean region off Perth and Bunbury in Western Australia.

In announcing the first zone, Federal Energy Minister Chris Bowen said the new industry “will provide opportunities to reduce emissions and fast track job and economic development opportunities for regional Australia, particularly in clean energy generation and manufacturing.”

What happens next?

More than 6,000 MW of potential projects have already been proposed for the first designated offshore wind zone off Gippsland, but the furthest advanced is the 2,200 MW Star of the South proposal.

The Danish-owned project would include up to 200 offshore wind turbines, located 7 to 25 kilometres from the coastline. Research agencies including RPS, CSIRO, and Monash, Deakin and Curtin Universities recently completed two years of detailed marine environmental surveys in the area, collecting data on marine ecology, animals, currents and waves that will inform the project’s design and construction.

The resulting environmental impact assessment reports are expected to be made public in 2023. Pending approvals, the developer has tentatively scheduled construction to begin in 2025, in order for the project to begin generating power before the closure of nearby Yallourn Power Station in 2028.

The Offshore Wind Energy in Australia report notes that the environmental effects of offshore wind farms are still largely unknown in the southern hemisphere, and their social acceptability is largely untested.

For now, communities and users of the waters in the Bass Strait off Gippsland are invited to provide feedback on the possible effects of offshore wind projects to the Department of Climate Change, Energy, the Environment and Water. Submissions closed in October 2022.