Bellwether Onshore Wind Farm by Acciona Energía is being developed as a flagship renewable energy hub for Western Australia’s Wheatbelt, targeting around 3 GW of capacity sited across 100,000 hectares of agricultural land in the shires of West Arthur, Williams, Wagin and Narrogin.

As of 2026, the project continues to move into active landholder engagement, local government consultation and early market outreach as Acciona seeks long‑term offtake and grid solutions to absorb multiple gigawatts of output. Acciona has also signaled late‑2020s construction window (around 2028 onwards) subject to approvals and commercial contracts.

Bellwether Wind Farm’s trajectory is also increasingly shaped by the rollout of the South West Interconnected System (SWIS) Transmission Plan. SWIS is unlocking new grid connection pathways near Darkan and surrounding areas and is also expected to serve other projects such as Synergy’s Scott River Wind Farm. This is critical infrastructure required to support projects of Bellwether’s scale.

Bellwether Wind Farm Fact Sheet

Developer: Acciona Energía

Location: Wheatbelt region, Western Australia (around Darkan/Arthur River/Wagin corridor)

Capacity: 3,000 MW (3 GW)

Infrastructure: Up to 400 turbines (subject to approvals and final design)

Land area: 100,000 hectares of mixed farmland

2026 Status: In development

Grid connection: Dependent on SWIS Transmission Plan upgrades and new terminal stations near Darkan

Construction outlook: Expected post-2028 (subject to approvals and grid readiness)

Operational outlook: Early 2030s

Key output: Utility-scale renewable power for SWIS grid decarbonization and industrial users

Development Timeline

2023-2024: Project formally announced and early feasibility completed

2024-2025: Landholder engagement and corridor definition across Wheatbelt region

2025: SWIS transmission constraints identified as key enabling factor

2025-2026: State transmission planning fast-tracked with Darkan node emerging as key connection point

2026: Project remains in development stage.Environmental, grid, and stakeholder consultation also ongoing

2027-2028 (expected): Final investment decision (FID) and major approvals window

2028 onward: Construction start

Early 2030s: Commissioning and grid integration

Acciona Energy’s Bellwether Project in Australia: World’s Second Largest Onshore Wind Farm

Reported September 29, 2024 – Acciona Energy’s Bellwether Wind Farm Project launch has just been announced. It will become the second largest onshore wind farm in the world upon completion with a capacity of 3,000 MW. The wind farm will be located in Perth, Australia and will require an investment of €2,500 million.

Construction is expected to start in 2025, while targeting commercial operations by 2030. The announcement also reinforces Acciona Energy’s international expansion strategy and joins other large projects that the company is developing in Australia, such as the MacIntyre wind project (1,026 MW).

The upcoming wind farm would immensely dwarf the next-largest projects in the entire country, including the 1,330-megawatt Golden Plains wind farm located in Victoria and Acciona’s 1,000-megawatt MacIntyre project located in Queensland.

Additionally, it would also significantly outstrip the proposed 100-turbine Ambrosia project near Collie, currently the largest wind project proposed for Western Australia.

Acciona Energy’s Bellwether Wind Farm Project Overview

Project name: Bellwether Project

Location: Perth

Capacity: 3,000 MW

Developer/contractor: Acciona

Cost: €2,500 million ($2.79 billion)

Commencement date: 2025

Completion date: 2030

Project Location

The project’s wind turbines would be built on 100,000 hectares of farmland based at the shires of West Arthur, Williams, Wagin and Narrogin, southwest of Perth.

Jeff Nitsch, who is the managing director of Acciona WA, also said Bellwether Onshore Wind Farm will be one of the largest in the world once it commences its operations. The wind farm targets 2030 completion date.

“The MacIntyre project in full scale is about 1,000 megawatts, the proposed Bellwether wind farm project could be two or three times that scale,” Nitsch added. “At that size, it could be the largest onshore wind farm outside of China”.

Nitsch also said the company was in discussions with the landowners and local governments about the proposed development. He also mentioned Acciona could be exporting power to the grid within six years.

Significance of the Project

Tristan Edis, director of Green Energy Markets, said Bellwether Onshore Wind Farm would be the most productive in Australia and one of the largest developments of its kind.

“Every major economy has a significant wind energy component in their electricity system, and that is expanding, whether it’s the United States, Canada, Germany, or even the United Kingdom,” he said.

If the developer’s estimates prove correct, the project could produce similar levels of power to the Collie power station, which is due to be decommissioned by the end of the decade.

Edis also said infrastructure is needed to connect the development to the South Western Interconnected System, along with customers to buy the gigawatts of electricity.

In Western Australia, wind farms typically need the involvement of Synergy, the state-owned retailer, or Alinta, which is one of the major private sector retailers – alongside others. Also on the table are agreements with large industrial consumers of electricity.

The 400 wind turbines will be built in West Arthur County. They will have a wingspan of 160 meters and a height of about 220 meters.

Residents Opinion on Bellwether Onshore Wind Farm Project

The proposal has been greeted with caution by some residents, such as third-generation farmer Karen Harrington. She said her family would support the development if the balance between energy and agriculture was maintained. “It could be a real bonus, it could almost guarantee the sustainability of our small towns,” Karen said.

Additionally, she called for the need of more guidance from the state government to protect agricultural land, as they welcome these renewable energy projects.

Energy Minister Reece Whitby also said he was working with the private sector to develop new renewable energy sources. This is while planning to retire all state-owned coal-fired power stations by 2030.

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