The three CETO 5 units have now accumulated more than 7,500 continuous operating hours. The first CETO 5 unit has now been operating for over 4,000 hours, with the second CETO 5 unit achieving over 2,000 operational hours. The third CETO 5 unit was installed successfully at the project site in early March and has now been operating alongside the two other CETO 5 units for over 1,000 hours. During the 7,500 continuous operational hours the units have experienced a range of sea states, including waves up to 4m in height.
Additionally, following connection to the grid in February, an initial period of grid commissioning, data collection and analysis has been completed and provided to the grid owner, Western Power, and the Perth Project has now been deemed to comply with Western Power Technical Rules. This allows consistent power generation and export to the grid to proceed.
Carnegie had previously planned to retrieve one of the first two CETO 5 units at the same time as the deployment of the third unit; however, this was deferred to allow all three units to operate as an array for a period of approximately 30 days. This period has now been reached, and preparations have now commenced to retrieve CETO Unit 1 and Pod 1 for a complete strip down, inspection and overhaul. The retrieval itself is planned to occur in the coming weeks, subject to suitable weather conditions.
Planned retrieval and inspection activities also allow for more informed operation and maintenance activities ahead of winter and include the removal of biofouling, inspection of seals in the CETO pump, inspection of bearings in the load path components and repair of some failed instrumentation. Importantly, the retrieval of CETO Unit 1 provides an opportunity to verify the retrieval method which is a key input into the ongoing operating philosophy associated with the Perth Project and CETO 6.
The primary purpose of the Perth Project is validation of the CETO 5 generation of Carnegie’s proprietary wave technology, in order to make the CETO 6 design as efficient and as low cost as possible. Carnegie’s design process for CETO primarily involves the development of sophisticated numerical or computational models that allow the simulation of CETO in real wave environments. The modelling enables design concepts to be tested rapidly without the risk and cost associated with ocean deployments. However, it is essential that real operational data is collected, analysed and used to calibrate these models to ensure that they are valid.
In order to effectively assess the performance of the CETO 5 unit, Carnegie has equipped the CETO units and the balance of plant with approximately 500 sensors generating 4 GB of data per day. This allows performance data such as pressure, flow, displacement, power, load, position and the like to be recorded and transmitted. This data is also used by the Process Control System and the Plant Operators to control the units and system response to optimise the overall performance of the plant. This optimisation process is now underway for the Perth Project.
As mentioned to date, the CETO Unit and system performance has been in line with expectations. An example of some initial measured performance analysis and comparison with modelled forecast performance is provided below for a sea state of Hs 2.4 m. The 40 kW measured output aligns well with that forecast by Carnegie’s computational models and provides early confirmation of the CETO 5 Unit’s power output.
The Perth Wave Energy Project was under construction for approximately 12 months, beginning with the installation of the CETO 5 unit offshore foundations in December 2013 and completing with the installation of the first CETO 5 unit in November 2014. Construction was proceeded by some 2 years of design, approvals, offtake, financing and procurement activity. More than $30m has been invested in the design, development and construction of the project. The CETO technology takes a unique approach to wave power by generating both power and water from the ocean swell while remaining fully submerged beneath the ocean surface, increasing its ability to survive large storms.
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. The technology is capable of generating power onshore or offshore depending upon the specific characteristics of a project site.
CETO technology characteristics include:
The CETO 5 technology being utilised in the Perth Wave Energy Project (PWEP) is configured to utilise the CETO pumps to pressurise water and deliver it onshore via an underwater pipe. Then, onshore, high-pressure water is used to drive 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.