You may require this approval if you intend to undertake any activity related to the exploration for, or the recovery or transport of greenhouse gasses or petroleum in Commonwealth waters (i.e. Australian waters outside the state and territory 3 mile boundary).
If your Offshore Project Proposal is approved, you will still need to have an Environmental Plan approved by the agency before you can undertake the related activity.
This approval is not required if the project has already been approved by the Environment Minister under the Environment Protection and Biodiversity Conservation Act.