The retrieval was successfully completed on the first attempt by using its hydraulic “quick connect” technology to disconnect the Unit from the seabed foundation. The disconnection was then followed in succession by the de-ballasting of the Buoyant Actuator, floating up of the Pump assembly on site and then towing the complete Unit back to the Australian Marine Complex (AMC) in Henderson.
The Unit has now been lifted out of the water and returned to Carnegie’s staging area within the AMC to begin the onshore inspection and overhaul process.
The successful retrieval of the unit on the first attempt has validated Carnegie’s “hot swap” operating and maintenance philosophy. This involves the rapid installation and retrieval of units for maintenance purposes which avoids the need to carry out any maintenance offshore where it is expensive and often impossible in most of the prevailing conditions at a commercial wave project site.
The retrieval is also important as it now allows Carnegie’s in house engineering and design team to inspect the unit onshore and gather valuable data. The Unit will be completely stripped down, to allow for non-destructive testing, and in depth inspection. The Unit will then be overhauled as required and re-assembled, prior to beginning onshore re-testing of the CETO Unit in advance of offshore re-installation.
After having successfully installed all three CETO 5 Units on the first attempt through November to March, the goal is to re-install Unit 1 and progressively retrieve Units 2 and 3 during winter when installation and retrieval conditions are more challenging. Carnegie’s aim to have a CETO 5 Unit continuously operate throughout winter.
The Project has now achieved more 8,500 continuous operational hours during which the units have experienced a range of sea states, including waves up to 5.7m in height.