Significant Progress on Perth Wave Energy Project
Wave energy developer Carnegie Wave Energy Limited has provided an update on the recent progress of the Perth Wave Energy Project.
Carnegie has made significant progress on the assembly and testing stage of the Perth Wave Energy Project in advance of the project’s final commissioning and operation phase.
Noteworthy recent progress includes the completion of the offshore preparations in advance of the deployment of the CETO unit, completion of construction of the onshore plant including installation of all power generation and conditioning equipment on Garden Island, and nearing completion of the testing of the CETO units.
Unit assembly and integration testing program progress
Over the past months, Carnegie has been working through a rigorous program of integration testing of the CETO units in advance of offshore installation and commissioning. This testing program has been designed to test and verify that individual components meet specification, component interfaces conform and component subsystems are integrated and tested. This allows Carnegie the opportunity to identify and remedy problems before deploying the CETO units offshore. The time spent on integration testing provides significant benefit to the Perth Project as well as valuable input into the design of future CETO projects. The testing program has included testing of the buoyant actuators, pumps, connectors, onshore and offshore pods, hoses, instrumentation and control system.
Carnegie recently took advantage of some suitable weather windows to complete a number of final offshore preparations ahead of the deployment of the CETO units. These activities included the installation of the lower foundation connector which connects the CETO unit to the offshore foundation previously installed. In addition, Carnegie has installed the offshore mudmat which will provide the base for the subsea hydraulic pod that helps regulate the flow from the CETO unit through the pipeline to the onshore plant. The short interconnection pipelines that connect the subsea pods to the rest of the pipeline system have also now been installed in preparation for the deployment of the CETO units and subsea pods.
Onshore plant construction completed
Final construction of the onshore plant, located on Garden Island, Western Australia, has been completed with the site and building works complete and the onshore hydraulic pod, motors, generators, process control system and grid connection also installed.
Unit Installation and Project Commissioning
Carnegie expects to complete its onshore system integration tests shortly before commencing offshore installation of the CETO units and final commissioning the Project. Carnegie will implement a conservative staged deployment strategy that brings on capacity of the plant in a controlled and gradual manner minimising installation and operational risk. Project commissioning involves the installation of CETO Unit 1 and an initial fault finding and operational optimisation period to identify, improve and/or correct any “infant” operating issues.
The integration testing program, currently nearing completion, is carried out to reduce the likely extent of in-ocean fault finding however it is anticipated that an initial unit will require some level of intervention and/or rectification either offshore or onshore. Where relevant the same corrective actions are carried out on Units 2 and 3 prior to their deployment.
Once CETO Unit 1 is operational, CETO Unit 2 will be installed and a new fault finding and optimisation period undergone, and importantly the interaction of multiple wave units analysed.
This is then followed by the installation and optimisation of the final CETO unit.
Offshore Activities Planning
A weather window is a period of wind and wave conditions that allows a planned marine operation to be performed safely and effectively. Weather windows are a critical consideration in planning any offshore activities but particularly for a demonstration project like the Perth Project, and especially for the installation of the first CETO 5 unit. For initial Unit deployments, both the period of installation, as well the initial operational period requires a low to moderate sea state to minimise the risk of component or system damage, and to maximise the ability to intervene should it be required.
The vessels being used and components being deployed are typically susceptible to the maximum wave height during installation. Historical maximum wave height off Garden Island (in 2009 – 2011) can be seen in the graph below. As would be expected, it shows that the maximum wave height is higher in the winter months than in the summer months and highlights that avoiding the winter months is the lowest risk approach to the planning of offshore construction and installation activities.
The CETO system is different from other wave energy devices as it operates under water where it is safer from large storms and invisible from the shore. Power can be generated either offshore or onshore. The fully submerged buoys can drive seabed pump units deliver high pressure fluid onshore via a subsea pipe to standard hydroelectric turbines, generating zero-emission electricity. The high-pressure water can also be used to supply a reverse osmosis desalination plant, replacing or reducing reliance on greenhouse gas-emitting, electrically-driven pumps usually required for such plants. Alternatively, the movement of the buoys can drive pumps and generators offshore that are contained within the buoy itself with power delivered back to shore through subsea cables.