Tenax Energy Pty Ltd (the Proponent) proposes to install up to 456 marine turbines on the seafloor in Clarence Strait, 50km north of Darwin. Preliminary engineering designs proposed 15 metre rotors spinning under the power of ocean currents and tides, to generate electricity for approximately 70% of tidal cycles.
The Project would include tidal energy generators and associated submarine cables, switching gear, transformer and substation at Glyde Point to provide a connection to the Darwin/Katherine grid. Designs may evolve with time, but designs presented in the Notice of Intent (NOI) proposed marine turbines placed on gravity base structures within a lease area of approximately 1691 hectares. A 2.3 hectare area is proposed for the submarine cables (approximate length 23km). The total amount of potential energy able to be generated from this Project is estimated at 1 036 000 MWh/year. To manage the increased capacity on the Darwin/Katherine electricity grid, and to refine designs, the Project site would be developed in several phases, including a pilot stage.
The Clarence Strait Tidal Energy Project (the Project) has offshore and onshore components. The offshore component is located in Clarence Strait, between Gunn Peninsula and Melville Island, Tiwi Islands. The onshore part of the Project is a linear alignment located between a point north west of Glyde Point and the northern most extent of the proposed infrastructure corridor associated with the deferred Glyde Point development site.
On the 18 December 2008 the Proponent submitted a Notice of Intent for the Project for assessment under the Northern Territory (NT) Environmental Assessment Act 1982 (EA Act). On 12 September 2009 the Northern Territory Minister for Natural Resources, Environment and Heritage (the Minister) determined that the Project required formal assessment under the EA Act at the level of an Environmental Impact Statement (EIS). Issues of concern contributing to this decision included:
- The technology is relatively new and environmental impacts are largely unknown or potentially significant;
- Potential impacts to marine species including coral reef communities;
- A number of rare and threatened species and listed migratory species and communities occur in the proposal’s impact area;
- The area provides important feeding grounds for sea turtles and dugong and consequently may be important to the traditional owners of the region;
- Disturbance of seabed impacting the erosion, transportation and deposition of sediments;
- Potential impacts to recreational and tourism activities in the area;
- Potential impacts to local and international shipping needs in the area;
- Potential disturbance to maritime heritage and Aboriginal cultural heritage; and EIS Guidelines – July 2013 Clarence Strait Tidal Energy Project – Tenax Energy 4
- Potential impacts to water quality from material inputs such as antifouling treatments.
The Proponent referred this proposal to the Australian Government under the Environment Protection and Biodiversity Conservation (EPBC) Act. On 28 January 2009, the Project was deemed to be a controlled action requiring assessment and approval under the EPBC Act before it can proceed. The controlling provisions are:
- Listed threatened species and communities (sections 18 and 18A);
- Listed migratory species (sections 20 and 20A); and
- Commonwealth marine areas (section 23 & 24A).
The Project will be assessed under a bilateral agreement between the NT and Australian Governments or an accredited assessment process. The assessment approach will be decided jointly by both governments, to streamline the process while satisfying requirements of the EPBC Act and EA Act.
These Guidelines are to assist the Proponent in preparing an EIS for the Clarence Strait Tidal Energy Project, in accordance with Clause 8 of the NT Environmental Assessment Administrative Procedures of the EA Act, and Part 8 of the EPBC Act. The NT Environment Protection Authority (NT EPA) will assess and report on the prepared EIS for the Project, after consultation with the public, advisory agencies and the Australian Government. The Project will then require approval from the responsible NT (consent) Minister(s), and from the Australian Minister under the EPBC Act before it can proceed.
Information about the Project and its relevant impacts, as outlined in this document, is to be provided in the EIS. This information should be sufficient to allow:
- The NT EPA to make informed recommendations to the Minister and the Australian Government in accordance with the EA Act; and
- The Australian Government Minister to make an informed decision on whether or not to approve, under Part 9 of the EPBC Act, the taking of the action for the purposes of each controlling provision.
Note: The Guidelines were issued to the Proponent on 8 July 2009, valid for a period of two years. On 4 July 2011 the Proponent applied for an extension to the period allowed for submission of the EIS. A two-year extension was granted by the NT Minister to the period in which the EIS is to be prepared and submitted by the Proponent for the Clarence Strait Tidal Energy Project. On 14 June 2013 the Proponent submitted further request to the NT EPA for extension of the period open for submission of the draft EIS. A further two year period has subsequently been granted.