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Open Sea Operating Experience to Reduce Wave Energy Cost

Periodic Reporting for period 3 - OPERA (Open Sea Operating Experience to Reduce Wave Energy Cost)

Reporting period: 2018-08-01 to 2019-07-31

Europe is endowed with abundant wave energy which could cover some 10% of its electricity need with a clean, predictable and job-creating resource, in which EU companies are at the forefront of its exploitation with little dependence on foreign suppliers. There remain important technical challenges to bring down costs to within investors’ reach. As a top priority, open-sea operating experience must be analysed to focus R&D efforts on identifying and solving problems uncovered in open-sea deployments. However, to this day, most wave energy R&D does not have access to open-sea operating data as it not shared by the companies that sponsored open-sea tests.

OPERA will remove this roadblock by collecting and sharing two years of open-sea operating data of a floating Oscillating Water Column (OWC) wave energy converter. In addition the project will be the first open-sea experience for four cost-reducing innovations that will be advanced from TRL3-4 to TRL5. Together, these four innovations have a long-term cost reduction potential of over 50%. These are: a 50% more efficient turbine, latching and predictive control, a shared mooring system for wave energy similar to those that have reduced mooring costs 50% in aquaculture, and an elastomeric mooring tether that reduces peak loads at the hull-mooring connection 70% and thus addresses one of the most pressing challenge for structural survivability of wave energy devices. Documenting and sharing this open-sea experience will also induce a step-change in our knowledge of risk and uncertainties, costs and societal and environmental impacts of wave energy.

The consortium brings together world leaders in wave energy research from 4 European countries, the IPR owners and most advanced teams to exploit each of these innovations.
The project entailed first a nationally-funded phase of open-sea testing at BiMEP in “benchmark” configuration of the floating OWC, with shared mooring, conventional tether, Wells turbine and non-predictive control algorithms. The OPERA-funded phase integrated three additional cost-reducing innovations into the OWC: biradial turbine, novel elastomeric tether and advanced control. These innovations underwent thorough lab-testing, prior de-risking in the Mutriku shoreline wave power plant. Sensor integration in the “benchmark” configuration of the floating OWC permited to monitor its structural and power performance, as well as sub-system reliability and survivability.

Process instrumentation was deployed in 2016 and the floating OWC device with a Wells turbine was grid connected at BiMEP by December 2016. This first deployment was mainly nationally-funded and has provided more than one year of baseline experimental data to be used in OPERA. In parallel, project partners carried out preparatory and pre-test activities aimed at de-risking the four project innovations. Testing of the new biradial air turbine at Mutriku shoreline plant was completed in 2018. A second prototype deployment took place at BiMEP from October 2018 to July 2019. It included the novel turbine, control algorithms and elastomeric mooring tethers. Experimental data collected from the field tests were used to validate the innovation potential and inform long term cost reduction.

The following technical results can be highlighted:
• Successful first open-sea deployment of baseline configuration of floating wave energy prototype (dubbed MARMOK-A-5) for 21 months and 2 consecutive winters.
• MARMOK-A-5 has survived rough seas of 14 m maximum wave height.
• End of 12-month testing of biradial turbine and advanced control algorithms at Mutriku.
• Comprehensive results analysis of testing campaigns at Mutriku and at BiMEP.
• Technical results confirm that the project KPI targets are achievable.
• Open-sea redeplyoment, commissioning, operation and final retrieval of MARMOK-A-5.
• Successful testing of elastomeric mooring tethers, biradial turbine and advanced control algorithms at BiMEP (Deployment 2).
• Results of the applicability of IEC Technical Specifications using open sea data.
• Monitoring of safe offshore operations and logistics.
• Periodic technical risk assessment and corresponding mitigations actions.
• Preliminary results of economic, life-cycle and social impact assessment for wave energy.
• Dissemination and communications actions in line or beyond initial targets.

From the very beginning, the Consortium has proactively sought any activity supporting the successful exploitation of the project results. After detailed analysis of each Key Exploitable Result, the partners willing to go to the market with the following innovations are:
• Floating OWC device and shared mooring configuration: IDOM;
• PTO based on the bi-radial air turbine: KYMANER;
• Elastomeric tether for mooring systems: UNEXE;
• Advanced control algorithms for WECs: IDOM, KYMANER supported by academic and research partners.

The exploitation plan details the innovation and maturity aspects of the technologies, the market sectors, key drivers, users and other stakeholders, as well as commercialisation issues and actions to reduce risks.
Analysis of data collected from the various testing campaigns indicate that the project can contribute to the expected impacts. Performance assessment of the biradial turbine in real-sea operation has shown that it is 55% more efficient than the Wells turbine, 50% mooring peak load reduction was verified during the second deployment and the power production increase potential measured at Mutriku up to 30%. Globally, these improvements translate into a cost-reduction of over 50%.

The main impacts are focused on the following two categories:

Direct project impacts:
a) Significantly increasing technology performance: 50% long-term cost-reduction potential, thanks to 50% more efficient air turbine, and 30% increase in power production with advanced control algorithms.
b) Evaluating and reducing life-cycle environmental impact based on the new experience and data on operating conditions in the open sea.
c) Open sea operating data and first real application of IEC Technical Specifications will bring cohesion, coherence and strategy in the development of wave energy technologies.
d) Reducing risks, time and costs of technology deployment by improved modelling, planning and logging of maritime operations.
e) Real operating data will inform and enable design for reliability, which reduces maintenance costs directly, and will allow use of preventive and condition based maintenance strategies, which reduces overall operating costs.

Wider impacts:
a) Improving EU energy security: long term cost-reduction will make a major contribution to facilitate wave energy to be part of the future European energy mix.
b) Wave energy is more predictable than and complementary with wind and solar energy, and can thus help manage intermittency, allowing larger amounts of variable output renewable sources in the grid.
c) Nurturing the supply chain of the nascent ocean energy industry, by validating components and systems that can make a step change in real operating conditions.
d) Job creation potential of wave energy is in the order 10,000 new jobs in Europe.
e) Achieving competitive wave energy would contribute to a sustainable, clean and secure energy mix.
Floating device with shared mooring
Open-sea testing of baseline MARMOK-A5 configuration at BiMEP
RBR virtuoso pressure gauge deployed in front of Mutriku
Biradial turbine at Mutriku shoreline plant
Elastomeric mooring tether prepared for testing at DMaC
Dry testing of biradial turbine at IST
Triaxys surface following wave buoy deployed at BiMEP
Offshore operations at BiMEP
Refitted prototype with biradial turbine
Towing out operation of MARMOK-A5 prototype
Elastomeric mooring tether on deck for second deployment