The planning authority has granted extra time to a Spanish-owned company to erect a further 76 wind turbines along the Woakwine Range, west of Millicent.

Iberdrola already operates 112 wind turbines at Lake Bonney and the extension proposal dates back to 2012.

It has successfully applied to the Limestone Coast Southern Regional Assessment Panel for permission to extend the existing planning approval.

Under the terms of the latest approval, the additional 76 turbines must be erected and operational by May 12, 2028.

Now trading as Woakwine Windfarm Pty Ltd, the project was previously granted extensions in 2018 and 2020.

The panel met in Mount Gambier last week to consider the application.

The minutes reveal the panel believed the applicant has demonstrated they are pursuing the application and have had unforeseen interruptions to finalising it.

To date, Woakwine Windfarm Pty Ltd has invested more than $10m in the project, including development costs ($5.5m), grid connection studies ($1m), land payments ($2m), employee salaries, wind measurement campaign and other costs.