Planning & projects |
CorPower Ocean in wave energy breakthrough
CorPower Ocean’s C4 Wave Energy Converter (WEC) has completed the first cycle of the ocean commissioning program at the Agucadoura site in northern Portugal
NOW PROVEN AT COMMERCIAL scale, at the exposed Atlantic test site, CorPower Ocean’s C4 device has demonstrated unique ability to tune and detune according to varying sea states, limiting response to extreme storm waves (up to 18.5m) while amplifying motion and power capture in regular waves using novel phase control technology. The progression marks a crucial milestone for wave energy addressing the two major obstacles which have hampered commercial adoption to date – survivability and efficient power generation in normal ocean conditions. The inflection point provides a firm signal of wave
Above: The C4 Wave Energy Convertor
Below: The blue curve shows the wave height estimated by onboard sensors during Nov 4, 2023, with waves up to 18.5m
Bottom: Power measurement from on-land substation power meter showing the peak export of 592kW
energy’s readiness for widescale adoption. Since deployment in August 2023, all key aspects of the C4 system functions have now been successfully verified, including power export to grid, automated control and monitoring of the system as well as safe Operations and Maintenance (O&M) methods. The collected data allowed calibration of the digital twin, an extensive numerical model used to predict the system behaviour. Measured motion and power output data from the machine operating with novel ‘WaveSpring’ phase control has slightly exceeded predictions by the digital twin for the machinery settings used. The first operational phase has been successfully concluded by disconnecting and towing the C4 device back to CorPower Ocean’s on-land base in Viana do Castelo for its first planned maintenance cycle. This demonstration of efficient O&M methods is a key goal of the C4 deployment program, to support scale-up to utility scale wave farms in the future. After completing a first on-land check-up and
maintenance cycle, C4 will be re-deployed at the Agucadoura site, and the demonstration program
continued. Further details on results from the first phase of C4 operations is provided below.
Storm survivability The survivability of the C4 WEC has been verified by
weathering four major storms, with confirmation of the ability to re-commence operations and power export to the grid after each storm. To remind, CorPower C4 operates reliably through Babet and Aline storms (
corpowerocean.com). The most energetic period was experienced during November 4th with storm Domingos sending swell to the site with wave heights up to 18.5m, reported by the Hydrographic Institute of Portugal as a historical record for the northern region. The CorPower C4 set a new storm survivability record (
corpowerocean.com)
CorPower Ocean and its Pilot Access Program (PAP) partners have been able to verify the design principles for robust operation in extreme waves offered by the Survival mode of the CorPower C4 device. Operating in the detuned Survival mode, which is the natural state of the system, the device displayed very small response to incident waves despite the WEC hull becoming fully submerged during wave peaks on a regular basis during these storms. In the plot below, the blue curve shows the wave height estimated by onboard sensors during November 4th 2023, with waves up to 18.5m, where the green curve shows the machinery motion as measured by the gearbox encoders to a few decimetres at most. The low machinery motion (range of decimetres) in these extreme waves confirms the effectiveness of the detuning principle used by the survival mode, with almost two orders of magnitude smaller machinery motion compared to the incident waves. The verification of very low response to storm waves is seen as one of the most important outcomes of the C4 ocean demonstration so far. Storm survivability has historically been one of the biggest challenges for wave energy devices.
Tuned operation The survivability results can be compared to the
measured data with C4 operating in tuned mode where up to 3m machinery motion has been observed in 1m incident waves. By activating the WaveSpring phase control technology the system starts oscillating in phase with the waves, which has been confirmed to strongly amplify the machinery response to the incident waves.
Tuning and detuning – a key feature for competitive wave energy The ability to tune and detune the device according to ocean conditions, limiting the response to storms and amplifying the motion and power capture in regular
30 | April 2024 |
www.waterpowermagazine.com
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