Final Report Summary - TOWERPOWER (Continuous monitoring of the structural condition of the tower and supporting structure of floating and static offshore wind turbines)
Executive Summary:
The TowerPower project has developed a Continuous Structural Monitoring (CSM) system providing real-time structural analysis of the wind turbine tower structure through the application of a novel integration of Non-destructive Testing (NDT) techniques and advanced electronic communication. This would allow to drastically reduce the incidence of repairs/replacements, and associated downtime.
In fact, NDT techniques which are currently avaible in the market provide defect detection for components but do not offer continuous monitoring of the entire wind turbine structure.
The TowerPower consortium was therefore born to put together SME-AGs, which were fully aware of the system requirements but lacked of knowledge and research capacity to develop the system, and leading Research and Technology Development (RTD) partners providing access to broad knowledge which was required to develop the TowerPower system.
Project Context and Objectives:
The needs addressed and estimated impact
The TowerPower consortium aimed to address the following issues in the field of wind turbines :
• The high O&M costs of offshore wind turbines compared to on-shore wind turbines (2 to 6 times higher),
• The towers’ failures (which greatly incide on O&M costs) ;
• The lack of established structural monitoring industry dedicated to the wind sector ;
• The lack of SMEs resources dedicated to develop ad hoc monitoring solutions.
TowerPower consortium therefore identified and committed itself to fill the need for a cost-effective automated monitoring systems that do not need regular human intervention, particularly for offshore installations.
TowerPower project aimed at developing an innovative tool to inspect and control the deterioration in these structures. This tool provides the most suitable strategy to achieve significant and measurable improvements in the availability, reliability and lifetime of offshore wind turbines in the foreseeable future, and thus increase the competitiveness of wind energy production, in comparison to other power generation technologies.
More specifically, the benefits of the TowerPower system include:
• An increased wind energy competitiveness in the EU market with potential savings of €37 million in electricity production ;
• Wind turbines’ extended life and productivity from reduced O&M costs for Offshore Wind Turbines (OWT) ;
• An increased maintenance safety through the use of an economically viable inspection solution ;
• A bigger SMEs’ involvement and a boosted employment potential for 4,960 SMEs in this sector ;
• A reduction in greenhouse gas emission within the energy industry through the proliferation of wind energy.
Besides, the outcome of this project will provide the wind farm owners, operators and the insurers with extremely valuable data on which to base decisions of extending the life of the wind turbines.
Finally, the TowerPower project produced a best practice and standardisation approach for test methods and implemented a programme of information and training for inspection personnel. This added a great value to the wind sector, as there were no standards available at the moment for the inspection of these structural components.
Objectives
The objectives of TOWERPOWER project developments were the following:
• To design and validate AE techniques for complex tubular support structures, thick walled columns and grout support joints ;
• To increase AE performance ;
• To develop transducers and sensor systems, marinated and permanently mounted ;
• To implement a hardware solution, DAQ and control ;
• To implement a software solution, database and communications ;
• To combine the developed NDT techniques and sensor systems into a single, reliably operating System.
Project Results:
In order to achieve the objectives of the project, the activities in the Work Programmes (WPs) were structured into three separate phases to illustrate the stages and advancement through the project.
Phase 1: Development of new scientific knowledge of how the existing AE, and SM methods and systems can be customised to lend themselves to continuous structural monitoring of offshore structures to monitor the grout structure joints in offshore installations.
WP1 – Scientific knowledge and system specification (Leader : TWI)
The initial specification document (Deliverable D1.1) was written, and updated during the course of the project as the requirements were continuously discussed by the comsortium. The detailed information about the specifications for each component and updated details were added to the Final Specifications deliverable (Deliverable D1.2). The final specification document (Deliverable D1.2) was also finalised.
The overall system requirements and specifications was presented including geometry of offshore wind turbine, damage mechanisms such as grout damage, fatigue cracks, loose bolts or corrosion and specifications of the Structural Health Monitoring Techniques including Acoustic Emission, vibration analysis (modal analysis) and guided waves.
Functional analyses performed at system and subsystem level were shown in order to obtain a list of the requirements leading to a marketable solution.
The mock up designs and available samples for their construction were presented, along with the drawings and explanation of future experiments. The following points were achieved:
Collate existing knowledge on wind structural monitoring
Create the TOWERPOWER system functional specification
Design and procurement of test samples and mock-ups
TowerPower system specifications: TOWERPOWER system concept, Overall system requirements and Constituent system requirements
Phase 2: Realisation of all NDT techniques and possibly GW as well as all the related software and hardware components, to create a continuous monitoring and inspection system for the tower and supporting structure of floating and static offshore wind turbines. System integration, testing and validation were carried out. The developed system is initially tested under laboratory conditions.
WP2 - Study of techniques and analysis tools (Leader : TWI)
Propagation of elastic with different features and the interaction with defects was studied. The analysis was initially carried out using numerical models with COMSOL. The models did assess the practical implications of the placement of the transducers optimising the excitation and reception of the wave modes. Wave modes that minimise these losses were selected and their suitability for detection of typical defects was evaluated.The results of numerical simulations did direct the experimental studies.
Experimental studies in laboratory were performed and environmental conditions were assessed. Experimental test in laboratory validated modelling results. An NDT procedure parameters and environmental parameters were also considered.
Transducers placement study and design of sensor array were investigated for an optimum sensors location as well as validation of techniques for continuous monitoring of the structural condition.
Definition of parameters such as wave mode, ultrasound frequency, transducer distribution type and configuration to achieve the defect sensitivity set down in the system specification.The sensor array application for continuous monitoring was validated.
The conclusions and results obtained along this WP2 are summarised below:
D2.1
The objective was to assess the effectiveness of the guided wave technique as a structural monitoring tool for the tower of an offshore wind turbine. The objective was to detect defects in the metallic structure, debonding of the metallic structure and the grout and finally defects in the grout.
It was proved experimentally and numerically that the guide wave technique allows good energy transmission despite the high dissipation of the grout. Moreover, simulations showed that this technique detects defects in the steel (transition piece and tower) which is well documented but also debonding between the grout and the steel. This is very important as these defects are one of the main reasons of the degradation of towers.
The simulations showed also that the main mode propagating is the torsional (shear) mode and that a distance of 10cm between successive transducers is advisable in order to obtain good wave front and significant energy transmitted through the grout.
D2.2
Determination of the ability of the Acoustic Emission technique to detect and localise defects in the grout by putting acoustic emission sensors either in the transition piece or the pile or both. The challenge of detecting AE emission coming from defects in the grout was the fact that the high attenuation of AE waves in cements generally.
Measurements were carried out on a mock-up developed by CETIM and speed propagation and attenuation results observed allowed the correlation with the simulations. It has been proved both experimentally and numerically that the main mode propagating in the structure is the shear mode. Shear mode is non dispersive and would allow a very precise localization of the defects.
The use of the linear bulk viscosity in simulations allowed correlating the attenuation of the AE wave with measurements. Subsequent simulations of the propagation of AE wave in the tower structure allowed the determination of the area of coverage of each AE sensor based on noise levels, AE source minimum signal amplitude and localization technique.
This will ultimately determine the number and frequency of the sensors necessary for each offshore wind turbine tower after an assessment of noise levels and the strength of the signals.
WP3 - Transducers, sensor arrays and electronics development (Leader : CETIM)
ACOUSTIC EMISSION INSTRUMENTATION OF THE TOWER
The acoustic emission sensors positioning have been determined in Deliverable D2.2. The sketch of sensors positioning strategy is given again below on Figure 3. The positioning have been optimized thanks to the new information collected within the tests on the propagation mock-up.
Position of the sensors is determined in order to perform a planar location of the AE sources generated within the grout.
Thanks to the information collected from simulation, tests on propagation mock-up and models presented by end-users, one can imagine 3 or 4 rows of sensors installed on the transition piece, with most of sensors rows near the sea surface or underwater.
Choice of the frequency of the sensors
In order to determine the best solution for the choice of the acoustic emission sensors, additional tests have been performed on the propagation mock-up with different kinds of AE characteristics. The objective is to determine the most sensitive type of sensor, for the detection of AE cracks, in the specific area of the grout and transition piece.
Hsu-Nielsen artificial AE sources have been generated along the length of the mock-up and the response to different sensors coupled at approximately the same location recorded.
According to the results, it appears that the maximum amplitude is recorded in the transition piece for sensors resonant around 150-200 kHz. This result is consistent with propagation results usually obtained in steel equipment.
WP4 - Data acquisition, graphical user interface and system integration (Leader : INNORA)
Graphical User Interface (GUI) signal processing & Analytics
The TOWERPOWER system is a wind turbine tower structural health monitoring system featuring both Acoustic Emission and Guided Waves NDT techniques. It facilitates remote monitoring without necessity of the operator’s physical presence on site.
The above is accomplished by a secure and high-performance data transfer mechanism that allows the transmission over the Internet and the visualization and processing on operator’s device.
In detail, the TOWERPOWER system set-up is organized around two main locations:
a) the Remote location is the asset’s location where the TOWERPOWER system is installed and conducts the monitoring;
b) the Base Station consists the terminal where the generated data are stored and are available for further analysis and visualisation thought the TOWERPOWER GUI.
The software comprises of the following modules that collaborate and communicate to make the data available to the end user:
• The File Parser and Converter module is responsible for translating the files acquired by the hardware into a file format that will be used for convenient storing and processing of the data. This facilitates smooth handling of the data and transparency with respect to the acquisition hardware. Both the Acoustic Emission and Guided Waves data are stored in the TOWERPOWER BASE Station PC in a specific format regardless of the original data form. The implementation of the parsing module makes this mechanism independent from the acquisition systems generated file format and allows the re-usage in multiple applications.
• Network Shared Folder: This mechanism facilitates the connection between the remote location (Wind Turbine) and the local site (Base Station). The central TOWERPOWER PC establishes a stable Local Area Network (LAN) over Ethernet cable to the acquisition systems in order to retrieve and convert the generated data. The available Internet connection allows to the implemented mechanism automatically synchronize the generated data to the PC located in the Base Station where the TOWERPOWER GUI operates.
• Database: The TOWERPOWER database stores the data associated features. For the retrieved data a feature extraction is performed and along with any relevant metadata such as the timestamp, or acquisition parameters are stored within the database while the raw signal data is stored within a folder structure for easier manipulation. The stored information can be used for historical purposes and data comparison of the same asset between different time periods.
• The TOWERPOWER GUI consists the main component of the implemented software. Along the Database, operates at the Base Station PC and provides a complete solution for the visualization and analysis of the generated monitoring data. A series of plugins were developed with respect to the widely used signal analysis and GW/AE techniques. A chain-like architecture is supported where the operator can perform elaborate analysis techniques by combining various plugins together as they see fit. Also, the historic data stored on application’s database allows monitoring over asset’s condition throughout the time. The Graphical User Interface was developed as a desktop application for multiple operation systems. The variety of the available tools allow the in-depth analysis and validation of the asset’s condition, speeds up the monitoring process and the maintenance procedures.
• Additionally, an experimental CNN Machine Learning analysis module was created to investigate the potential of automating defect analysis. The module was built around Convolutional Neural Networks (CNNs), a widespread machine learning tool that is able to uncover spatial relationships within the data thereby achieving pattern recognition without the need of hand-crafted features. The CNN was trained on a small dataset acquired by CETIM through pencil-break experiments on the transition-piece mock-up structure developed within the scope of the project. The adoption of Machine Learning principals on the field of defect analysis holds significant promise and we aim to refine our techniques as more data become available from the experiments on the mock-up structures and other field trials.
We should note that the above software modules constitute the foreground for Innora SA.
Phase 3 : The developed system prototype is tested in a real environment during field trials that are carried out on an offshore wind turbine tower.
WP5 - Field trials and system validation CYLSOLAR
The asset where the TowerPower system was validated
The field trials were conducted on an onshore vertical wind turbine provided by NENUPHAR WIND. This asset consisted in a prototype that was built in 2014 at Fos-Sur-Mer (France) on the Mediterranean coast. The 600kW turbine is the biggest operating vertical axis wind turbine in the world with height of 40m and diameter 50m. The wind turbine was equipped with different types of sensors that validate the aerodynamic model and the control system developed by NENUPHAR WIND. The sensors also provided fundamental feedback on technological issues concerning the rotor architecture, the control of blade angle, the power conversion and the accessibility.
The installation of the TOWERPOWER system leveraged the asset’s monitoring mechanism by providing valuable information concerning the structure’s condition. Since prototype’s final aim was the creation of commercial horizontal axis off-shore turbines, the knowledge on structure’s frail points and deterioration rhythm was critical. The development of preventing mechanisms that extend structure’s life was equally important for the success of NENUPHAR WIND company.
In addition, the asset offered the required facilities to accommodate the inspection equipment for the span of the trial test period (one month) and direct technical support was available by specialized staff on site.
Installation
The TOWERPOWER equipment was spread in three different locations that communicated and interacted with each other in order to have the information available on the end user.
The location no 1 is the Wind Turbine’s tower.
The GW/AE acquisition systems were placed on the second level (Figure 4) of the tower where other inspection tools were also accommodated. Sensors where attached on critical points of interest as indicated by NENUPHAR WIND. The acquisition systems were connected to corresponding working stations (laptops) that served as intermediate for the systems’ manipulation.
The TOWERPOWER PC was installed on an Auxiliary Room (location no 2) around 110m far from the tower base. The location of the TOWERPOWER PC was selected to be in a different position to ensure a stable 3G internet connection signal and direct physical access in case of failure. The two ends were connected via Ethernet cable. An Ethernet extender was placed outdoors in the middle distance to overcome Ethernet cable distance limitations, maintain data transition high speed and minimize data packages loss. The extender was placed in a waterproof case that protected it from extreme weather conditions. The TOWERPOWER PC was responsible for the communication and data exchange with the acquisition systems and the data conversion.
The data exchange concerning the TOWERPOWER system was implemented using the FTP protocol that allows secure file transmitting between terminals. The routine was communicating periodically (once per 12 hours) with the TOWERPOWER system, in order to download the latest GW generated data and convert it in the standard .HDF5 file format. Consequently, using the OneDrive file storage and synchronization tool the files where directly uploaded on the cloud and were available on third party terminals. Likewise, a second routine was responsible to access periodically the Vallen system (once per hour), pulled the latest generated data regarding the AE signals and transfer it over the internet. For this purpose, a 3G USB router was attached on the TOWERPOWER PC to allow internet connection for the data transfer and remote access on the terminal itself and the installed equipment. As soon as the file synchronization process was completed, the exported .HDF5 data files were accessed from the third party PC (location no 3 ) where the TOWERPOWER GUI software was operating in order to plot and analyze the results further.
Equipment
The dedicated equipment was selected cautiously to maintain high performance, accuracy and storage capacity during the outdoors trial test. The main aim was to validate systems functionality, fulfil the onsite requirements such as (weather, temperature conditions e.t.c) and minimize the points of failure.
Sensors
Twelve AE sensors were distributed along two independent wind tower circumferences corresponding to two different tower heights. These were split in in the following way: six sensors located in the bottom of the tower and six sensors located in level 3.
Two arrays of GW sensors were placed in level 2. These arrays were held using a custom magnetic holder. The dimensions of the wind turbine did not allow the deployment of a full size transducer’s array. Therefor these were positioned at both sides of a tower weld.
TOWERPOWER system was located in the second level of the tower. The associated laptop managed the data acquisition using TOWERPOWER software.
Through transmission techniques, only the signal amplitude measurements are used, whereas with pulse-echo techniques the time of flight needs to be measured on a time base calibrated for distance to allow damage to be located. In the present scenario, only pulse-echo was used.
In order to compare results and performances of the TOWERPOWER system, a commercial Vallen AE system was also installed in the tower. The system is an AMSY6 MB6 acquisition system equipped with 12 acoustic emission channels. These 12 channels were uniformly distributed on 2 rows; one at the top of the tower below the turbine and another at the bottom of the turbine just above the access door. Meanwhile, the acquisition system is located near the TOWERPOWER system, at the center of the tower.
The AE sensors are connected to the system through BNC cables positioned along the tower walls. The sensitive part of the channel is composed of:
• A piezoelectric resonant sensor with its peak frequency around 200kHz. The sensor is maintained to the structure using magnet holders. The coupling is ensured by silicone grease.
• A 34dB preamplifier adapting and filtering the signal in the bandwidth 80-1000 kHz. It allows the signal to be transmitted on long distances. Preamplifiers are maintained to the structure using integrated magnet holders.
Both AE and GW were tested during the systems installation. However, there was a complication when splitting the signal from the AE transducers into the two systems (TOWERPOWER and Vallen). It was finally decided that only Vallen would be acquiring data from the AE sensors to ensure the correct data collection. This way the data analysis and the study of the features classification would not be jeopardised.
AE activity was then saved and stored on the computer associated, using Vallen software. AE activity has been recorded during an entire month, alternately during shutdown and operation periods. The AE activity was then linked to parametric data supplied by NENUPHAR (wind speed, rotating speed, and displacement on strain gauges).
TOWERPOWER PC
As TOWERPOWER PC served a high-performance INTEL NUC NUC7I5BNK mini-pc equipped with suitable memory, storage and computational capacity. The main specifications are :
Processor: 5th generation Intel® Core™ i5-5250U processor
RAM: KINGSTON Memory DDR4 SODIMM 2133MHz, Single Rank, 8GB
Memory: KINGSTON SSD 240G GB SATA III
Power: DC power connector (12V - 19V)
Wireless Adapter: Intel® Dual Band Wireless-AC and Bluetooth 4.0
Ethernet: Integrated Intel® Gigabit LAN
USB ports: USB 3.0 ports
Also, a Netgear Mobile Broadband USB stick 3G adapter was attached on TOWERPOWER PC and provided 3G internet connection (Figure 6).
Results
COMMUNICATION AND ACQUISITION ON TOWERPOWER GUI
The asset was monitored over the span of one month while being fully operational. During the monitoring phase different acquisition thresholds and settings parameters where tested in order to achieve measurement accuracy and eliminate false positive results.
No significant results were obtained due to the nature of the present scenario. There were no changes in the signal signature over the monitoring period.
DATA ANALYSIS OF VALLEN DATA RECORDED DURING SEPTEMBER PERIOD
AE raw data has been recorded continuously during one month using Vallen acquisition system and the 12 acquisition channels. Due to the huge amount of data, the analysis has been focused on the period between September 6th 3pm and September 15th 10am. More particularly, a high activity phase has been analyzed in detail. This phase is characterized by intense activity especially on sensor 2 (top of the tower).
A focused analysis has been performed on data recorded on September 9th from 10.40am to 8pm (picture below).
Analysis has been performed using a Vallen setup developed specifically for this project. Intensities and activities during this period have been analysed and linear localization calculated, based on waves’ velocity and positions of sensors.
RMS data highlights the functioning and shutdown phases of the tower. RMS value increases drastically for each start of the tower, which is consistent with activity based on friction phenomenon.
The analysis of the activity and intensity of the acoustic emission recorded during the high activity phase show that they are drastically increasing during a short period of time, mainly on sensor 2 (located on top of the tower, near the emergency access ladder).
Localization algorithms convergence is thus verified for both linear localizations (top and bottom of the tower). One can imagine an additional raw of sensors at half height of the tower in order to configure a planar localization (tower assimilated to a pressure equipment ferrule). Distances less than 5 meters should be sufficient to ensure a satisfying planar location.
The recorded activity could correspond to a particular event appeared on the structure as well as some noise due to environmental conditions. To confirm the origin of this particular activity, the acoustic emission waves recorded during this period have been compared to the parametric inputs recorded on the structure. Three different inputs have been analysed during these tests: wind speed, rotation speed of the tower and loads recorded on the strain gauges.
The first observation on the analysis is that the wind speed has no particular effect on the AE activity. Shutdown and operating periods are easily detected since the AE activity is drastically reduced when rotations per minute is null.
On the other hand, the intense activity phase is completely decorrelated with the parametric inputs recorded, with no impact of their evolution on the AE activity. We also know for sure that this activity is not related to any human activity in the tower since its access is forbidden during running periods.
Although this result could be seen as disappointing since the origin of this activity remains unknown, one can also consider this result as very interesting regarding the ability of the AE system to detect unplanned events such as cracks, etc.
Hence, an AE activity has appeared without any disturbance from environmental conditions or even normal functioning of the tower and the natural background noise of the tower doesn’t seem to be a barrier to the detection of AE transient signals.
As it has been defined in the DOW the objective of the field tests is mainly to investigate the capacity of the Tower Power system on site conditions regarding installation, setting up equipment, gathering test data. Interpretation of test data remains superficial since the conditions of the structure are not well known.
The main goal of a deeper analysis and former test campaign should be to monitor “live” what event happens on the structure by a continuous communication with Nenuphar team on site.
This will suppose a permanent access to the saved data and some alarms levels to alert the human controller.
Conclusion
TOWERPOWER software and hardware components collaborate efficiently during the test. By applying both Acoustic Emission and Guided Waves inspection techniques on the vertical wind turbine situated in Fos-sur-Mer the TOWERPOWER system performance was validated and the produced results concerning asset’s condition evaluated.
Potential Impact:
1. Potential impact
The application of the TOWERPOWER as a standard nondestructive testing (NDT) solution could have multiple benefits for the different stakeholders on the Global Wind Energy industry.
On the field of safety, it ensures the structural integrity of wind turbine towers remotely without the continuous presence of the OWT maintenance personnel on site. As a result, it prevents the staff’s unnecessary exposure on unsafe conditions and minimizes the risk of working accidents. Regarding the environmental aspects, it supports and promotes the wind power, a rising eco-friendly energy source against the traditional non-renewable ones. In addition, it contributes to the protection of the seabed since it reports on structure’s condition. In addition, it allows taking action before a collapse of the wind tower due to extensive defects comes. Technologically it introduces novel techniques that modernize the common NDT practices and exploits fully breakthrough technologies such machine learning and cloud computing.
2. Main dissemination activities
During the project lifetime (01/03/2014 – 31/10/2017) TowerPower conducted various dissemination activities aimed at :
• Raising awareness of potential clients of the TOWERPOWER system about the proposed innovation;
• Teasing new potential distributors and installers of remote monitoring systems in view of triggering contractual selling license requests;
• Teasing new potential purchase advisors of remote monitoring systems for wind turbines in view of leveraging the licensing spread.
• Rising awareness of the general energy and NDT professional communities about the proposed innovation;
The main target stakeholders were:
• Offshore wind farm operators,
• Onshore wind farm operators,
• Offshore wind turbine installers,
• Onshore wind turbine installers,
• Wind turbine Maintenance operators,
• Wind turbine manufacturers, especially structure parts manufacturers.
The dissemination activities were of 3 types :
1) Development of marketing materials to support any communication through different media ;
2) Promotion of the TOWERPOWER system through:
• Printed articles to be published in professional magazines and newspapers ;
• Electronic articles for publication on the Partners’ websites and newsletters ;
• Participation to key conferences and fairs ;
• Use of social networks to outreach international communities ;
• A demonstration event at the test site.
3) Scientific publications.
All dissemination activities followed clear-cut guidelines set by the plan for use and dissemination of foreground (PUDF). Indeed, the PUDF stated the dissemination strategy of the project, the aim of the dissemination actions, the communication and dissemination tools to be used, and the activities and mechanisms for information exchange with various stakeholders.
The first draft of the plan for use and dissemination of foreground (PUDF) was developed and released at M5 and placed on the project website intranet. The final version of the PUDF was released at the end of the project.
Any dissemination material was screened by the Project Steering Committee (PSC) to ensure that potential for patents and intellectual property is not endangered. Also, the approval of the PSC was required for dissemination of any information related to the project. Dissemination took the form of passive and active dissemination. Passive dissemination will include the inclusion of project results on the partners’ websites, and disclosure of information through project brochures to relevant associations.
Key dissemination tools and activities conducted by the project are described below :
The website (www.towerpower.eu) was created and made available by TWI in March 2014 (M1 of the Project). It has been used as an important dissemination channel, describing the project activities and outcomes, project consortium and project documents targeting external wider public.
The domain name was registered for a period of 3 years (until end of September 2017) and the website will be maintained after the project ends for dissemination proposals.
The website consists of two mains areas, a public and a private one. The latter is reserved to the members of the consortium to consult project’s documents (deliverables, meetings’ minutes and presentations).
The website is cross-referenced from the websites of individual partners.
Logo, PPT and deliverable templates.
A logo was created to establish an identity for the project. Templates for PowerPoint presentations and deliverables were designed to ensure congruent presentation to external audiences.
Press releases.
A press article about the project kick-off was prepared by CAPENERGIES for dissemination by all the partners, starting with their company websites in May and July 2014. The article was replicated by other environment- and marine-focused websites and magazines. Press releases were drafted in English with translations in French, Greek, Italian and Spanish. The project kick-off press release was published in Cyprus (WLB website), France (Capenergies website and retrieved by other French websites such as actu-environnement.com) Greece (Innora website), Italy (AIPnD website), Norway (TDA website), Spain (Tecopy and Cylsolar websites) and UK (TWI website). All in all, it is estimated that the press release reached about 500 to 2000 people.
In October 2016, M. Anthony Fletcher, on behalf of the European Commission's Cordis news service, has been commissioned as an external writer for the TIPIK consortium to an article highlighting successful EU-funded projects. The TOWERPOWER project has been selected. The article has appeared here: http://cordis.europa.eu/news/home_en.html has been published in the Research_EU magazine and carried in several online medias. The Project Manager of Capenergies was interviewed. This article was used as a press release stating the latest development of the project by all partners.
Some partners as Capenergies (France), AIPND (Italy) and AEE (Spain) also shared the project actualities through their newsletters and national networks thorough the length of the project, targeting institutional stakeholders and companies in the wind energy sectors as well as a European-wider public.
22 publications in the professional networks like Twitter, LinkedIn and Facebook were also used to disseminate the project’s articles, press releases, participation in events and advertisement to approx.. 35 000 persons or entities in Europe.
Project documentation
Dissemination materials produced by the project include:
• Posters
• Leaflet summarizing the concept of the project
• General leaflet presenting the project key outcomes
Video clip.
A video clip of 3 minutes was produced to maximise the dissemination of the final results of the project in more dynamic and ludic ways and create opportunities and routes for exploitation. This video clip was uploaded on YouTube.
Project trainings and training material.
The techniques employed by the TowerPower system are a significant functional advancement to current inspection techniques and in order to enable effective use by maintenance crews, clear instruction and service manuals were created. In addition to the manuals, presentations with pictures and videos from the installation were created to convey the techniques and subsystems used in the final TowerPower system. Thus, even after the project’s end, each SME, whether an NDT systems provider or a wind turbine operator, will be able to train its personnel.
A training session for the operators on how to install and operate the system and its sub components was conducted. Also, the feedback from the training of the first personnel (questions, unexplained material etc.) was used to update the material produced.
Project workshops.
The research center TWI was in particular involved in organizing 3 technical presentations through workshops in their premises as well as in specialized professional events. These sessions were arranged to discuss the issues relating to the integrity in offshore wind farms specifically looking at issues regarding the deployment of condition monitoring systems and the application of existing standards for FFS/ECA assessment on the predominant structures in the offshore wind industry.
Participation in events.
In total, project partners participated in 33 events reaching at least 40 000 people during the project period (March 2014 to October 2017). For more detailed information, please refer to Deliverable D6.
3. Exploitation of results
The exploitation of the foreground, once further technical development of the pre-production system has been carried out, was mainly based on the sales of physical TOWERPOWER components and system, as well as services delivered by purchasing advisors.
The TOWERPOWER Consortium elaborated an exploitation plan of the project results, which takes care of advantaging the TOWERPOWER SME-AGs, as well as SME Participants, while guaranteeing their return on investments.
The agreement on which the consortium decided to exploit the project foreground relies on the following principles:
Each SME-AG and SME Participant must be paid back of its investment in the TOWERPOWER project out of the exploitation of the research results;
The TOWERPOWER Foreground exploitation plans must take into account the claimed Background one way or another (free license, patent license, negotiated lump sum, exploitation rights counterpart, etc.) on fair and reasonable grounds of normal business practice;
The SME-Ags and SME Participants will take advantage of a rapid and wide spread licensing mechanism or equivalent that will allow third parties to sell TOWERPOWER systems. Such a licensing mechanism will act as an accelerator of their return on investment in the European project;
When making profit out of the TOWERPOWER project results, the SME Participants must have a market competitive advantage upon any other company granted by the SME-Ags to sell the TOWERPOWER system;
Further development and investment for the production and full commercialization of the TOWERPOWER components and system are necessary after the end of the project to go onto the market with fully cost-competitive products. The amount of the financial investment needs was preliminary estimated during the project duration. The same for the further developments of pre-productive TowerPower systems.
A whole exploitation scheme, including the description of the Partners’ roles and the working rules of the licensing scheme, was developed.
A preliminary product cost and market analysis was performed, and kept confidential.
At the beginning of the project, partners agreed that possible intellectual property generated during the project would be jointly owned by the SMEs and the RTDs, with SMEs having the first option of exploiting the developments
Nevertheless, throughout the project duration, no request for formal protection of foreground was recorded by the Exploitation Manager (See Annex I - DoW - of the Grant Agreement).
After the conclusion of the project, Capenergies is willing to patent the TowerPower integrated system, upon condition that after carrying out further extensive testing (see chapter B.3.1) the system results to be potentially market-ready.
Furthermore, in order to enable Capenergies to patent the TowerPower full integrated system, those SME AGs currently owning the foreground related to the different components, have declared themselves ready to transfer their own foreground to the project coordinator.
As for the project results, the exploitable Foreground at the end of the Project consists in :
Acoustic Emissions, methods and apparatus for support structures condition monitoring ;
Sensor arrays, including accelerometers, ultrasonic and strains transducers, to transmit and receive signals ;
A control and acquisition system, including Ethernet-based communication and graphical user interface, to send, collect and process signals ;
The integrated TowerPower system for continuous monitoring of the structural condition of the tower and supporting structure of offshore wind turbines.
Principles for a fair exploitation of the Foreground
The following sections outline a plan for the commercial exploitation of the project final results by the SME-AGs and the SME Participants within the TOWERPOWER consortium.
General principles
The consortium agreed that the exploitation of the foreground will be based on the sales of physical TOWERPOWER components or systems, as well as services which will be delivered by purchasing advisors.
The exploitation plan, which the consortium agreed on, aimed at:
• advantaging the TOWERPOWER SME-AGs, as well as the SME Participants,
• guaranteeing their return on investments.
One condition was set to achieve the above-listed targets: the project results had to truly meet the performance expectations and consequently their markets (See market analysis in FPUD).
At the end of the project, these targets were not fully achieved since the TowerPower systems, components and services have not truly met the performance expectations, and consequently their markets.
Indeed, the TowerPower prototype needs to be further tested on real structures or large-scale components, with and without faults, for a longer period and in different environmental conditions (in order to test, for instance, the impact of extreme weather conditions on the prototype). Without extensive result validation and well established reference/test base, the system will not be commercially exploitable.
At the moment, the fact that the TowerPower prototype was tested in a limited time and environmental conditions prevents SME AGs and SMEs within the consortium to find potential end users.
Nevertheless, the consortium recognises the added-value of the TowerPower system. In fact, the TowerPower system:
- is a complete solution that combines an efficient continuous monitoring system and a flexible data analysis software suite;
- encloses an interesting technology that allows the system to detect defects that develop over time on an arbitrary area;
- gives an important insight into a new and interesting methodology for condition assessment, a market that will grow considerably in the years ahead;
- can also be used on infrastructure assets (e.g bridges where some of the partners are already involved in condition monitoring using more traditional sensors).
On this basis, after the end of the EU funding, the consortium is willing to carry on working on making the TowerPower prototype exploitable. The further testing phase is supposed to take at least 6 months.
Once the further testing phase has wholly proven the marketability of the prototype, Capenergies is willing to file a patent for the integrated system (in order to that, other SME AGs are willing to transfer their foreground to the Project coordinator), and consequently licensee its manufacturing and installation to chosen third parties.
All in all, the exploitation path will rely on the following principles:
● Each SME-AG and SME Participant must be paid back of its investment in the TOWERPOWER project out of the results exploitation;
● The SME-AGs and SME Participants will take advantage of a rapid and wide spread licensing mechanism or equivalent that will allow third parties to sell TOWERPOWER systems. Such a licensing mechanism was supposed to act as an accelerator of their return on investment in the European project;
● When making profit out of the TOWERPOWER project results, the SME Participants must have a market competitive advantage upon any other company granted by the SME-AGs to sell the TOWERPOWER system.
Use and dissemination of foreground
Implementation of the Foreground exploitation plan
Roles to play – SME-AG and SME individual claims
At the moment, no SME AGs and SME within the TowerPower consortium is keen on commercially exploit the TowerPower system because of the reasons explained above.
In general terms, seven main categories of stakeholders will be involved in the exploitation of the foreground:
1. TOWERPOWER component provider,
2. TOWERPOWER system integrator/distributor,
3. TOWERPOWER system installer/retailer,
4. Purchasing advisor, who will perform studies favourable to the implementation of TOWERPOWER systems,
5. Trainer qualified to deliver knowledge and know-how about the TOWERPOWER system,
6. Licensor,
7. Business Agent easing the development of a licensees’ network.
TowerPower’s SME AGs and SMEs are ready to transfer the foreground related to Components 1 , 2 and 3 to Capenergies in case it will decide to file a patent for the TowerPower integrated system.
Capenergies will then decide, in synergy with the SME-AG who initially own the different foregrounds, whom it wants to grant manufacturing license(s) for the integrated system to.
The licence(s) will be Non-exclusive.
The Component-manufacturing licensee(s) will bear all the industrialization costs, the counterpart being minimum purchase volumes guaranteed by the TOWERPOWER integrators’ community.
Whoever the chosen industrial partner(s) is, it/they will make a better price to the SME Participants than to any other TOWERPOWER system integrator.
The RTD Performers commit, through the signature of the Grant Agreement and the Consortium Agreement, to deliver all the knowledge and know-how required allowing Capenergies granting manufacturing licenses to others in case they wish to.
Sale of TOWERPOWER system to installers
Some SMEs in the network of TowerPower’s SME AGs have declared their interest in implementing the TOWERPOWER system in their wind turbines once the prototype will be fully commercially exploitable.
AEE got a letter of expression of interest in the TowerPower prototype from Esteyco. The company, which developed an innovative offshore wind turbine under the Elisa Project in the Canary Islands, has declared its interest in establishing commercial exploitation paths with the TowerPower Consortium.
Capenergies also got a letter of expression of interest in the TowerPower results and further development to come from NENUPHAR, the company which hosted the TowerPower prototype test.
In addition, SME-AGs have identified among its members several companies having a potential interest in the TowerPower integrated system. For instance, tower manufacturers need to implement Continuous Structural Monitoring systems with the aim of improve their products, so that they can supply the TowerPower system within their towers. Operators and Developers of Offshore Wind Farms need to monitor the behaviour of their assets to reduce maintenance costs. Some offshore service providers are offering complete maintenance solutions based on fault predictive models that require Continuous Structural Monitoring systems such as TowerPower.
Therefore, once the TowerPower integrated system will be marketable (after a further extensive testing phase), AEE, Cylsolar and Capenergies will look into finding companies that, within their networks, are interested in making Use of the Background and Foreground by packing (integrator) and distributing TOWERPOWER system.
TOWERPOWER system installers
Once the TowerPower integrated system will be marketable (after a further extensive testing phase), AEE, Cylsolar and Capenergies will look into finding companies that, within their networks, are interested in making use of the Background and Foreground by installing TOWERPOWER systems.
Purchasing advisors
Cylsolar intends to make Use of the Background and Foreground by selling sizing, design and implementation studies prior to installation of TOWERPOWER systems and/or by using their business network to ease the expansion of the licensing scheme.
Its return on investment in the TOWERPOWER project will come both from their direct study sales and from sales of TOWERPOWER systems. The second source of revenues will take the form of royalties on sales following their advice paid by SME-AGs upon presentation of evidences of their role in the deal conclusion with a client following their intervention, until their return on investment plus a bonus is ensured.
In some case, purchase advisors wish to develop also product-selling activities. The remuneration from royalties on study sales should be subject to clear-cut and auditable accounting of both activities.
Unfortunately, the project did not fully meet the expected results, the performance expectations and consequently their markets.
Indeed, the TowerPower prototype needs to be further tested on real structures or large-scale components, with and without faults, for a longer period (at least 6 months) and in different environmental conditions during the year 2018.
As long as an extensive result validation and well established reference/test base will not be available, the system will not be commercially exploitable for the SME AGs of the consortium.
Nevertheless, since the consortium recognises the added-value of the TowerPower system, even though the EU funding will be no longer available, it is willing to carry on working on making the TowerPower prototype exploitable.
Once the further testing phase has wholly proven the marketability of the prototype, Capenergies is willing to file a patent for the integrated system (in order to that, other SME AGs previously agreed to transfer their foreground to the Project coordinator), and consequently licensee its manufacturing and installation to chosen third parties, with a priority given to companies within AEE, Cylsolar and Capenergies’ networks. Consortium foresees that the integrated system will be ready for the market at Q3 2019.
List of Websites:
www.towerpower.eu
For any further information, please contact Paul Lucchese, Deputy Director of Capenergies by mail paul.lucchese@capenergies.fr
The TowerPower project has developed a Continuous Structural Monitoring (CSM) system providing real-time structural analysis of the wind turbine tower structure through the application of a novel integration of Non-destructive Testing (NDT) techniques and advanced electronic communication. This would allow to drastically reduce the incidence of repairs/replacements, and associated downtime.
In fact, NDT techniques which are currently avaible in the market provide defect detection for components but do not offer continuous monitoring of the entire wind turbine structure.
The TowerPower consortium was therefore born to put together SME-AGs, which were fully aware of the system requirements but lacked of knowledge and research capacity to develop the system, and leading Research and Technology Development (RTD) partners providing access to broad knowledge which was required to develop the TowerPower system.
Project Context and Objectives:
The needs addressed and estimated impact
The TowerPower consortium aimed to address the following issues in the field of wind turbines :
• The high O&M costs of offshore wind turbines compared to on-shore wind turbines (2 to 6 times higher),
• The towers’ failures (which greatly incide on O&M costs) ;
• The lack of established structural monitoring industry dedicated to the wind sector ;
• The lack of SMEs resources dedicated to develop ad hoc monitoring solutions.
TowerPower consortium therefore identified and committed itself to fill the need for a cost-effective automated monitoring systems that do not need regular human intervention, particularly for offshore installations.
TowerPower project aimed at developing an innovative tool to inspect and control the deterioration in these structures. This tool provides the most suitable strategy to achieve significant and measurable improvements in the availability, reliability and lifetime of offshore wind turbines in the foreseeable future, and thus increase the competitiveness of wind energy production, in comparison to other power generation technologies.
More specifically, the benefits of the TowerPower system include:
• An increased wind energy competitiveness in the EU market with potential savings of €37 million in electricity production ;
• Wind turbines’ extended life and productivity from reduced O&M costs for Offshore Wind Turbines (OWT) ;
• An increased maintenance safety through the use of an economically viable inspection solution ;
• A bigger SMEs’ involvement and a boosted employment potential for 4,960 SMEs in this sector ;
• A reduction in greenhouse gas emission within the energy industry through the proliferation of wind energy.
Besides, the outcome of this project will provide the wind farm owners, operators and the insurers with extremely valuable data on which to base decisions of extending the life of the wind turbines.
Finally, the TowerPower project produced a best practice and standardisation approach for test methods and implemented a programme of information and training for inspection personnel. This added a great value to the wind sector, as there were no standards available at the moment for the inspection of these structural components.
Objectives
The objectives of TOWERPOWER project developments were the following:
• To design and validate AE techniques for complex tubular support structures, thick walled columns and grout support joints ;
• To increase AE performance ;
• To develop transducers and sensor systems, marinated and permanently mounted ;
• To implement a hardware solution, DAQ and control ;
• To implement a software solution, database and communications ;
• To combine the developed NDT techniques and sensor systems into a single, reliably operating System.
Project Results:
In order to achieve the objectives of the project, the activities in the Work Programmes (WPs) were structured into three separate phases to illustrate the stages and advancement through the project.
Phase 1: Development of new scientific knowledge of how the existing AE, and SM methods and systems can be customised to lend themselves to continuous structural monitoring of offshore structures to monitor the grout structure joints in offshore installations.
WP1 – Scientific knowledge and system specification (Leader : TWI)
The initial specification document (Deliverable D1.1) was written, and updated during the course of the project as the requirements were continuously discussed by the comsortium. The detailed information about the specifications for each component and updated details were added to the Final Specifications deliverable (Deliverable D1.2). The final specification document (Deliverable D1.2) was also finalised.
The overall system requirements and specifications was presented including geometry of offshore wind turbine, damage mechanisms such as grout damage, fatigue cracks, loose bolts or corrosion and specifications of the Structural Health Monitoring Techniques including Acoustic Emission, vibration analysis (modal analysis) and guided waves.
Functional analyses performed at system and subsystem level were shown in order to obtain a list of the requirements leading to a marketable solution.
The mock up designs and available samples for their construction were presented, along with the drawings and explanation of future experiments. The following points were achieved:
Collate existing knowledge on wind structural monitoring
Create the TOWERPOWER system functional specification
Design and procurement of test samples and mock-ups
TowerPower system specifications: TOWERPOWER system concept, Overall system requirements and Constituent system requirements
Phase 2: Realisation of all NDT techniques and possibly GW as well as all the related software and hardware components, to create a continuous monitoring and inspection system for the tower and supporting structure of floating and static offshore wind turbines. System integration, testing and validation were carried out. The developed system is initially tested under laboratory conditions.
WP2 - Study of techniques and analysis tools (Leader : TWI)
Propagation of elastic with different features and the interaction with defects was studied. The analysis was initially carried out using numerical models with COMSOL. The models did assess the practical implications of the placement of the transducers optimising the excitation and reception of the wave modes. Wave modes that minimise these losses were selected and their suitability for detection of typical defects was evaluated.The results of numerical simulations did direct the experimental studies.
Experimental studies in laboratory were performed and environmental conditions were assessed. Experimental test in laboratory validated modelling results. An NDT procedure parameters and environmental parameters were also considered.
Transducers placement study and design of sensor array were investigated for an optimum sensors location as well as validation of techniques for continuous monitoring of the structural condition.
Definition of parameters such as wave mode, ultrasound frequency, transducer distribution type and configuration to achieve the defect sensitivity set down in the system specification.The sensor array application for continuous monitoring was validated.
The conclusions and results obtained along this WP2 are summarised below:
D2.1
The objective was to assess the effectiveness of the guided wave technique as a structural monitoring tool for the tower of an offshore wind turbine. The objective was to detect defects in the metallic structure, debonding of the metallic structure and the grout and finally defects in the grout.
It was proved experimentally and numerically that the guide wave technique allows good energy transmission despite the high dissipation of the grout. Moreover, simulations showed that this technique detects defects in the steel (transition piece and tower) which is well documented but also debonding between the grout and the steel. This is very important as these defects are one of the main reasons of the degradation of towers.
The simulations showed also that the main mode propagating is the torsional (shear) mode and that a distance of 10cm between successive transducers is advisable in order to obtain good wave front and significant energy transmitted through the grout.
D2.2
Determination of the ability of the Acoustic Emission technique to detect and localise defects in the grout by putting acoustic emission sensors either in the transition piece or the pile or both. The challenge of detecting AE emission coming from defects in the grout was the fact that the high attenuation of AE waves in cements generally.
Measurements were carried out on a mock-up developed by CETIM and speed propagation and attenuation results observed allowed the correlation with the simulations. It has been proved both experimentally and numerically that the main mode propagating in the structure is the shear mode. Shear mode is non dispersive and would allow a very precise localization of the defects.
The use of the linear bulk viscosity in simulations allowed correlating the attenuation of the AE wave with measurements. Subsequent simulations of the propagation of AE wave in the tower structure allowed the determination of the area of coverage of each AE sensor based on noise levels, AE source minimum signal amplitude and localization technique.
This will ultimately determine the number and frequency of the sensors necessary for each offshore wind turbine tower after an assessment of noise levels and the strength of the signals.
WP3 - Transducers, sensor arrays and electronics development (Leader : CETIM)
ACOUSTIC EMISSION INSTRUMENTATION OF THE TOWER
The acoustic emission sensors positioning have been determined in Deliverable D2.2. The sketch of sensors positioning strategy is given again below on Figure 3. The positioning have been optimized thanks to the new information collected within the tests on the propagation mock-up.
Position of the sensors is determined in order to perform a planar location of the AE sources generated within the grout.
Thanks to the information collected from simulation, tests on propagation mock-up and models presented by end-users, one can imagine 3 or 4 rows of sensors installed on the transition piece, with most of sensors rows near the sea surface or underwater.
Choice of the frequency of the sensors
In order to determine the best solution for the choice of the acoustic emission sensors, additional tests have been performed on the propagation mock-up with different kinds of AE characteristics. The objective is to determine the most sensitive type of sensor, for the detection of AE cracks, in the specific area of the grout and transition piece.
Hsu-Nielsen artificial AE sources have been generated along the length of the mock-up and the response to different sensors coupled at approximately the same location recorded.
According to the results, it appears that the maximum amplitude is recorded in the transition piece for sensors resonant around 150-200 kHz. This result is consistent with propagation results usually obtained in steel equipment.
WP4 - Data acquisition, graphical user interface and system integration (Leader : INNORA)
Graphical User Interface (GUI) signal processing & Analytics
The TOWERPOWER system is a wind turbine tower structural health monitoring system featuring both Acoustic Emission and Guided Waves NDT techniques. It facilitates remote monitoring without necessity of the operator’s physical presence on site.
The above is accomplished by a secure and high-performance data transfer mechanism that allows the transmission over the Internet and the visualization and processing on operator’s device.
In detail, the TOWERPOWER system set-up is organized around two main locations:
a) the Remote location is the asset’s location where the TOWERPOWER system is installed and conducts the monitoring;
b) the Base Station consists the terminal where the generated data are stored and are available for further analysis and visualisation thought the TOWERPOWER GUI.
The software comprises of the following modules that collaborate and communicate to make the data available to the end user:
• The File Parser and Converter module is responsible for translating the files acquired by the hardware into a file format that will be used for convenient storing and processing of the data. This facilitates smooth handling of the data and transparency with respect to the acquisition hardware. Both the Acoustic Emission and Guided Waves data are stored in the TOWERPOWER BASE Station PC in a specific format regardless of the original data form. The implementation of the parsing module makes this mechanism independent from the acquisition systems generated file format and allows the re-usage in multiple applications.
• Network Shared Folder: This mechanism facilitates the connection between the remote location (Wind Turbine) and the local site (Base Station). The central TOWERPOWER PC establishes a stable Local Area Network (LAN) over Ethernet cable to the acquisition systems in order to retrieve and convert the generated data. The available Internet connection allows to the implemented mechanism automatically synchronize the generated data to the PC located in the Base Station where the TOWERPOWER GUI operates.
• Database: The TOWERPOWER database stores the data associated features. For the retrieved data a feature extraction is performed and along with any relevant metadata such as the timestamp, or acquisition parameters are stored within the database while the raw signal data is stored within a folder structure for easier manipulation. The stored information can be used for historical purposes and data comparison of the same asset between different time periods.
• The TOWERPOWER GUI consists the main component of the implemented software. Along the Database, operates at the Base Station PC and provides a complete solution for the visualization and analysis of the generated monitoring data. A series of plugins were developed with respect to the widely used signal analysis and GW/AE techniques. A chain-like architecture is supported where the operator can perform elaborate analysis techniques by combining various plugins together as they see fit. Also, the historic data stored on application’s database allows monitoring over asset’s condition throughout the time. The Graphical User Interface was developed as a desktop application for multiple operation systems. The variety of the available tools allow the in-depth analysis and validation of the asset’s condition, speeds up the monitoring process and the maintenance procedures.
• Additionally, an experimental CNN Machine Learning analysis module was created to investigate the potential of automating defect analysis. The module was built around Convolutional Neural Networks (CNNs), a widespread machine learning tool that is able to uncover spatial relationships within the data thereby achieving pattern recognition without the need of hand-crafted features. The CNN was trained on a small dataset acquired by CETIM through pencil-break experiments on the transition-piece mock-up structure developed within the scope of the project. The adoption of Machine Learning principals on the field of defect analysis holds significant promise and we aim to refine our techniques as more data become available from the experiments on the mock-up structures and other field trials.
We should note that the above software modules constitute the foreground for Innora SA.
Phase 3 : The developed system prototype is tested in a real environment during field trials that are carried out on an offshore wind turbine tower.
WP5 - Field trials and system validation CYLSOLAR
The asset where the TowerPower system was validated
The field trials were conducted on an onshore vertical wind turbine provided by NENUPHAR WIND. This asset consisted in a prototype that was built in 2014 at Fos-Sur-Mer (France) on the Mediterranean coast. The 600kW turbine is the biggest operating vertical axis wind turbine in the world with height of 40m and diameter 50m. The wind turbine was equipped with different types of sensors that validate the aerodynamic model and the control system developed by NENUPHAR WIND. The sensors also provided fundamental feedback on technological issues concerning the rotor architecture, the control of blade angle, the power conversion and the accessibility.
The installation of the TOWERPOWER system leveraged the asset’s monitoring mechanism by providing valuable information concerning the structure’s condition. Since prototype’s final aim was the creation of commercial horizontal axis off-shore turbines, the knowledge on structure’s frail points and deterioration rhythm was critical. The development of preventing mechanisms that extend structure’s life was equally important for the success of NENUPHAR WIND company.
In addition, the asset offered the required facilities to accommodate the inspection equipment for the span of the trial test period (one month) and direct technical support was available by specialized staff on site.
Installation
The TOWERPOWER equipment was spread in three different locations that communicated and interacted with each other in order to have the information available on the end user.
The location no 1 is the Wind Turbine’s tower.
The GW/AE acquisition systems were placed on the second level (Figure 4) of the tower where other inspection tools were also accommodated. Sensors where attached on critical points of interest as indicated by NENUPHAR WIND. The acquisition systems were connected to corresponding working stations (laptops) that served as intermediate for the systems’ manipulation.
The TOWERPOWER PC was installed on an Auxiliary Room (location no 2) around 110m far from the tower base. The location of the TOWERPOWER PC was selected to be in a different position to ensure a stable 3G internet connection signal and direct physical access in case of failure. The two ends were connected via Ethernet cable. An Ethernet extender was placed outdoors in the middle distance to overcome Ethernet cable distance limitations, maintain data transition high speed and minimize data packages loss. The extender was placed in a waterproof case that protected it from extreme weather conditions. The TOWERPOWER PC was responsible for the communication and data exchange with the acquisition systems and the data conversion.
The data exchange concerning the TOWERPOWER system was implemented using the FTP protocol that allows secure file transmitting between terminals. The routine was communicating periodically (once per 12 hours) with the TOWERPOWER system, in order to download the latest GW generated data and convert it in the standard .HDF5 file format. Consequently, using the OneDrive file storage and synchronization tool the files where directly uploaded on the cloud and were available on third party terminals. Likewise, a second routine was responsible to access periodically the Vallen system (once per hour), pulled the latest generated data regarding the AE signals and transfer it over the internet. For this purpose, a 3G USB router was attached on the TOWERPOWER PC to allow internet connection for the data transfer and remote access on the terminal itself and the installed equipment. As soon as the file synchronization process was completed, the exported .HDF5 data files were accessed from the third party PC (location no 3 ) where the TOWERPOWER GUI software was operating in order to plot and analyze the results further.
Equipment
The dedicated equipment was selected cautiously to maintain high performance, accuracy and storage capacity during the outdoors trial test. The main aim was to validate systems functionality, fulfil the onsite requirements such as (weather, temperature conditions e.t.c) and minimize the points of failure.
Sensors
Twelve AE sensors were distributed along two independent wind tower circumferences corresponding to two different tower heights. These were split in in the following way: six sensors located in the bottom of the tower and six sensors located in level 3.
Two arrays of GW sensors were placed in level 2. These arrays were held using a custom magnetic holder. The dimensions of the wind turbine did not allow the deployment of a full size transducer’s array. Therefor these were positioned at both sides of a tower weld.
TOWERPOWER system was located in the second level of the tower. The associated laptop managed the data acquisition using TOWERPOWER software.
Through transmission techniques, only the signal amplitude measurements are used, whereas with pulse-echo techniques the time of flight needs to be measured on a time base calibrated for distance to allow damage to be located. In the present scenario, only pulse-echo was used.
In order to compare results and performances of the TOWERPOWER system, a commercial Vallen AE system was also installed in the tower. The system is an AMSY6 MB6 acquisition system equipped with 12 acoustic emission channels. These 12 channels were uniformly distributed on 2 rows; one at the top of the tower below the turbine and another at the bottom of the turbine just above the access door. Meanwhile, the acquisition system is located near the TOWERPOWER system, at the center of the tower.
The AE sensors are connected to the system through BNC cables positioned along the tower walls. The sensitive part of the channel is composed of:
• A piezoelectric resonant sensor with its peak frequency around 200kHz. The sensor is maintained to the structure using magnet holders. The coupling is ensured by silicone grease.
• A 34dB preamplifier adapting and filtering the signal in the bandwidth 80-1000 kHz. It allows the signal to be transmitted on long distances. Preamplifiers are maintained to the structure using integrated magnet holders.
Both AE and GW were tested during the systems installation. However, there was a complication when splitting the signal from the AE transducers into the two systems (TOWERPOWER and Vallen). It was finally decided that only Vallen would be acquiring data from the AE sensors to ensure the correct data collection. This way the data analysis and the study of the features classification would not be jeopardised.
AE activity was then saved and stored on the computer associated, using Vallen software. AE activity has been recorded during an entire month, alternately during shutdown and operation periods. The AE activity was then linked to parametric data supplied by NENUPHAR (wind speed, rotating speed, and displacement on strain gauges).
TOWERPOWER PC
As TOWERPOWER PC served a high-performance INTEL NUC NUC7I5BNK mini-pc equipped with suitable memory, storage and computational capacity. The main specifications are :
Processor: 5th generation Intel® Core™ i5-5250U processor
RAM: KINGSTON Memory DDR4 SODIMM 2133MHz, Single Rank, 8GB
Memory: KINGSTON SSD 240G GB SATA III
Power: DC power connector (12V - 19V)
Wireless Adapter: Intel® Dual Band Wireless-AC and Bluetooth 4.0
Ethernet: Integrated Intel® Gigabit LAN
USB ports: USB 3.0 ports
Also, a Netgear Mobile Broadband USB stick 3G adapter was attached on TOWERPOWER PC and provided 3G internet connection (Figure 6).
Results
COMMUNICATION AND ACQUISITION ON TOWERPOWER GUI
The asset was monitored over the span of one month while being fully operational. During the monitoring phase different acquisition thresholds and settings parameters where tested in order to achieve measurement accuracy and eliminate false positive results.
No significant results were obtained due to the nature of the present scenario. There were no changes in the signal signature over the monitoring period.
DATA ANALYSIS OF VALLEN DATA RECORDED DURING SEPTEMBER PERIOD
AE raw data has been recorded continuously during one month using Vallen acquisition system and the 12 acquisition channels. Due to the huge amount of data, the analysis has been focused on the period between September 6th 3pm and September 15th 10am. More particularly, a high activity phase has been analyzed in detail. This phase is characterized by intense activity especially on sensor 2 (top of the tower).
A focused analysis has been performed on data recorded on September 9th from 10.40am to 8pm (picture below).
Analysis has been performed using a Vallen setup developed specifically for this project. Intensities and activities during this period have been analysed and linear localization calculated, based on waves’ velocity and positions of sensors.
RMS data highlights the functioning and shutdown phases of the tower. RMS value increases drastically for each start of the tower, which is consistent with activity based on friction phenomenon.
The analysis of the activity and intensity of the acoustic emission recorded during the high activity phase show that they are drastically increasing during a short period of time, mainly on sensor 2 (located on top of the tower, near the emergency access ladder).
Localization algorithms convergence is thus verified for both linear localizations (top and bottom of the tower). One can imagine an additional raw of sensors at half height of the tower in order to configure a planar localization (tower assimilated to a pressure equipment ferrule). Distances less than 5 meters should be sufficient to ensure a satisfying planar location.
The recorded activity could correspond to a particular event appeared on the structure as well as some noise due to environmental conditions. To confirm the origin of this particular activity, the acoustic emission waves recorded during this period have been compared to the parametric inputs recorded on the structure. Three different inputs have been analysed during these tests: wind speed, rotation speed of the tower and loads recorded on the strain gauges.
The first observation on the analysis is that the wind speed has no particular effect on the AE activity. Shutdown and operating periods are easily detected since the AE activity is drastically reduced when rotations per minute is null.
On the other hand, the intense activity phase is completely decorrelated with the parametric inputs recorded, with no impact of their evolution on the AE activity. We also know for sure that this activity is not related to any human activity in the tower since its access is forbidden during running periods.
Although this result could be seen as disappointing since the origin of this activity remains unknown, one can also consider this result as very interesting regarding the ability of the AE system to detect unplanned events such as cracks, etc.
Hence, an AE activity has appeared without any disturbance from environmental conditions or even normal functioning of the tower and the natural background noise of the tower doesn’t seem to be a barrier to the detection of AE transient signals.
As it has been defined in the DOW the objective of the field tests is mainly to investigate the capacity of the Tower Power system on site conditions regarding installation, setting up equipment, gathering test data. Interpretation of test data remains superficial since the conditions of the structure are not well known.
The main goal of a deeper analysis and former test campaign should be to monitor “live” what event happens on the structure by a continuous communication with Nenuphar team on site.
This will suppose a permanent access to the saved data and some alarms levels to alert the human controller.
Conclusion
TOWERPOWER software and hardware components collaborate efficiently during the test. By applying both Acoustic Emission and Guided Waves inspection techniques on the vertical wind turbine situated in Fos-sur-Mer the TOWERPOWER system performance was validated and the produced results concerning asset’s condition evaluated.
Potential Impact:
1. Potential impact
The application of the TOWERPOWER as a standard nondestructive testing (NDT) solution could have multiple benefits for the different stakeholders on the Global Wind Energy industry.
On the field of safety, it ensures the structural integrity of wind turbine towers remotely without the continuous presence of the OWT maintenance personnel on site. As a result, it prevents the staff’s unnecessary exposure on unsafe conditions and minimizes the risk of working accidents. Regarding the environmental aspects, it supports and promotes the wind power, a rising eco-friendly energy source against the traditional non-renewable ones. In addition, it contributes to the protection of the seabed since it reports on structure’s condition. In addition, it allows taking action before a collapse of the wind tower due to extensive defects comes. Technologically it introduces novel techniques that modernize the common NDT practices and exploits fully breakthrough technologies such machine learning and cloud computing.
2. Main dissemination activities
During the project lifetime (01/03/2014 – 31/10/2017) TowerPower conducted various dissemination activities aimed at :
• Raising awareness of potential clients of the TOWERPOWER system about the proposed innovation;
• Teasing new potential distributors and installers of remote monitoring systems in view of triggering contractual selling license requests;
• Teasing new potential purchase advisors of remote monitoring systems for wind turbines in view of leveraging the licensing spread.
• Rising awareness of the general energy and NDT professional communities about the proposed innovation;
The main target stakeholders were:
• Offshore wind farm operators,
• Onshore wind farm operators,
• Offshore wind turbine installers,
• Onshore wind turbine installers,
• Wind turbine Maintenance operators,
• Wind turbine manufacturers, especially structure parts manufacturers.
The dissemination activities were of 3 types :
1) Development of marketing materials to support any communication through different media ;
2) Promotion of the TOWERPOWER system through:
• Printed articles to be published in professional magazines and newspapers ;
• Electronic articles for publication on the Partners’ websites and newsletters ;
• Participation to key conferences and fairs ;
• Use of social networks to outreach international communities ;
• A demonstration event at the test site.
3) Scientific publications.
All dissemination activities followed clear-cut guidelines set by the plan for use and dissemination of foreground (PUDF). Indeed, the PUDF stated the dissemination strategy of the project, the aim of the dissemination actions, the communication and dissemination tools to be used, and the activities and mechanisms for information exchange with various stakeholders.
The first draft of the plan for use and dissemination of foreground (PUDF) was developed and released at M5 and placed on the project website intranet. The final version of the PUDF was released at the end of the project.
Any dissemination material was screened by the Project Steering Committee (PSC) to ensure that potential for patents and intellectual property is not endangered. Also, the approval of the PSC was required for dissemination of any information related to the project. Dissemination took the form of passive and active dissemination. Passive dissemination will include the inclusion of project results on the partners’ websites, and disclosure of information through project brochures to relevant associations.
Key dissemination tools and activities conducted by the project are described below :
The website (www.towerpower.eu) was created and made available by TWI in March 2014 (M1 of the Project). It has been used as an important dissemination channel, describing the project activities and outcomes, project consortium and project documents targeting external wider public.
The domain name was registered for a period of 3 years (until end of September 2017) and the website will be maintained after the project ends for dissemination proposals.
The website consists of two mains areas, a public and a private one. The latter is reserved to the members of the consortium to consult project’s documents (deliverables, meetings’ minutes and presentations).
The website is cross-referenced from the websites of individual partners.
Logo, PPT and deliverable templates.
A logo was created to establish an identity for the project. Templates for PowerPoint presentations and deliverables were designed to ensure congruent presentation to external audiences.
Press releases.
A press article about the project kick-off was prepared by CAPENERGIES for dissemination by all the partners, starting with their company websites in May and July 2014. The article was replicated by other environment- and marine-focused websites and magazines. Press releases were drafted in English with translations in French, Greek, Italian and Spanish. The project kick-off press release was published in Cyprus (WLB website), France (Capenergies website and retrieved by other French websites such as actu-environnement.com) Greece (Innora website), Italy (AIPnD website), Norway (TDA website), Spain (Tecopy and Cylsolar websites) and UK (TWI website). All in all, it is estimated that the press release reached about 500 to 2000 people.
In October 2016, M. Anthony Fletcher, on behalf of the European Commission's Cordis news service, has been commissioned as an external writer for the TIPIK consortium to an article highlighting successful EU-funded projects. The TOWERPOWER project has been selected. The article has appeared here: http://cordis.europa.eu/news/home_en.html has been published in the Research_EU magazine and carried in several online medias. The Project Manager of Capenergies was interviewed. This article was used as a press release stating the latest development of the project by all partners.
Some partners as Capenergies (France), AIPND (Italy) and AEE (Spain) also shared the project actualities through their newsletters and national networks thorough the length of the project, targeting institutional stakeholders and companies in the wind energy sectors as well as a European-wider public.
22 publications in the professional networks like Twitter, LinkedIn and Facebook were also used to disseminate the project’s articles, press releases, participation in events and advertisement to approx.. 35 000 persons or entities in Europe.
Project documentation
Dissemination materials produced by the project include:
• Posters
• Leaflet summarizing the concept of the project
• General leaflet presenting the project key outcomes
Video clip.
A video clip of 3 minutes was produced to maximise the dissemination of the final results of the project in more dynamic and ludic ways and create opportunities and routes for exploitation. This video clip was uploaded on YouTube.
Project trainings and training material.
The techniques employed by the TowerPower system are a significant functional advancement to current inspection techniques and in order to enable effective use by maintenance crews, clear instruction and service manuals were created. In addition to the manuals, presentations with pictures and videos from the installation were created to convey the techniques and subsystems used in the final TowerPower system. Thus, even after the project’s end, each SME, whether an NDT systems provider or a wind turbine operator, will be able to train its personnel.
A training session for the operators on how to install and operate the system and its sub components was conducted. Also, the feedback from the training of the first personnel (questions, unexplained material etc.) was used to update the material produced.
Project workshops.
The research center TWI was in particular involved in organizing 3 technical presentations through workshops in their premises as well as in specialized professional events. These sessions were arranged to discuss the issues relating to the integrity in offshore wind farms specifically looking at issues regarding the deployment of condition monitoring systems and the application of existing standards for FFS/ECA assessment on the predominant structures in the offshore wind industry.
Participation in events.
In total, project partners participated in 33 events reaching at least 40 000 people during the project period (March 2014 to October 2017). For more detailed information, please refer to Deliverable D6.
3. Exploitation of results
The exploitation of the foreground, once further technical development of the pre-production system has been carried out, was mainly based on the sales of physical TOWERPOWER components and system, as well as services delivered by purchasing advisors.
The TOWERPOWER Consortium elaborated an exploitation plan of the project results, which takes care of advantaging the TOWERPOWER SME-AGs, as well as SME Participants, while guaranteeing their return on investments.
The agreement on which the consortium decided to exploit the project foreground relies on the following principles:
Each SME-AG and SME Participant must be paid back of its investment in the TOWERPOWER project out of the exploitation of the research results;
The TOWERPOWER Foreground exploitation plans must take into account the claimed Background one way or another (free license, patent license, negotiated lump sum, exploitation rights counterpart, etc.) on fair and reasonable grounds of normal business practice;
The SME-Ags and SME Participants will take advantage of a rapid and wide spread licensing mechanism or equivalent that will allow third parties to sell TOWERPOWER systems. Such a licensing mechanism will act as an accelerator of their return on investment in the European project;
When making profit out of the TOWERPOWER project results, the SME Participants must have a market competitive advantage upon any other company granted by the SME-Ags to sell the TOWERPOWER system;
Further development and investment for the production and full commercialization of the TOWERPOWER components and system are necessary after the end of the project to go onto the market with fully cost-competitive products. The amount of the financial investment needs was preliminary estimated during the project duration. The same for the further developments of pre-productive TowerPower systems.
A whole exploitation scheme, including the description of the Partners’ roles and the working rules of the licensing scheme, was developed.
A preliminary product cost and market analysis was performed, and kept confidential.
At the beginning of the project, partners agreed that possible intellectual property generated during the project would be jointly owned by the SMEs and the RTDs, with SMEs having the first option of exploiting the developments
Nevertheless, throughout the project duration, no request for formal protection of foreground was recorded by the Exploitation Manager (See Annex I - DoW - of the Grant Agreement).
After the conclusion of the project, Capenergies is willing to patent the TowerPower integrated system, upon condition that after carrying out further extensive testing (see chapter B.3.1) the system results to be potentially market-ready.
Furthermore, in order to enable Capenergies to patent the TowerPower full integrated system, those SME AGs currently owning the foreground related to the different components, have declared themselves ready to transfer their own foreground to the project coordinator.
As for the project results, the exploitable Foreground at the end of the Project consists in :
Acoustic Emissions, methods and apparatus for support structures condition monitoring ;
Sensor arrays, including accelerometers, ultrasonic and strains transducers, to transmit and receive signals ;
A control and acquisition system, including Ethernet-based communication and graphical user interface, to send, collect and process signals ;
The integrated TowerPower system for continuous monitoring of the structural condition of the tower and supporting structure of offshore wind turbines.
Principles for a fair exploitation of the Foreground
The following sections outline a plan for the commercial exploitation of the project final results by the SME-AGs and the SME Participants within the TOWERPOWER consortium.
General principles
The consortium agreed that the exploitation of the foreground will be based on the sales of physical TOWERPOWER components or systems, as well as services which will be delivered by purchasing advisors.
The exploitation plan, which the consortium agreed on, aimed at:
• advantaging the TOWERPOWER SME-AGs, as well as the SME Participants,
• guaranteeing their return on investments.
One condition was set to achieve the above-listed targets: the project results had to truly meet the performance expectations and consequently their markets (See market analysis in FPUD).
At the end of the project, these targets were not fully achieved since the TowerPower systems, components and services have not truly met the performance expectations, and consequently their markets.
Indeed, the TowerPower prototype needs to be further tested on real structures or large-scale components, with and without faults, for a longer period and in different environmental conditions (in order to test, for instance, the impact of extreme weather conditions on the prototype). Without extensive result validation and well established reference/test base, the system will not be commercially exploitable.
At the moment, the fact that the TowerPower prototype was tested in a limited time and environmental conditions prevents SME AGs and SMEs within the consortium to find potential end users.
Nevertheless, the consortium recognises the added-value of the TowerPower system. In fact, the TowerPower system:
- is a complete solution that combines an efficient continuous monitoring system and a flexible data analysis software suite;
- encloses an interesting technology that allows the system to detect defects that develop over time on an arbitrary area;
- gives an important insight into a new and interesting methodology for condition assessment, a market that will grow considerably in the years ahead;
- can also be used on infrastructure assets (e.g bridges where some of the partners are already involved in condition monitoring using more traditional sensors).
On this basis, after the end of the EU funding, the consortium is willing to carry on working on making the TowerPower prototype exploitable. The further testing phase is supposed to take at least 6 months.
Once the further testing phase has wholly proven the marketability of the prototype, Capenergies is willing to file a patent for the integrated system (in order to that, other SME AGs are willing to transfer their foreground to the Project coordinator), and consequently licensee its manufacturing and installation to chosen third parties.
All in all, the exploitation path will rely on the following principles:
● Each SME-AG and SME Participant must be paid back of its investment in the TOWERPOWER project out of the results exploitation;
● The SME-AGs and SME Participants will take advantage of a rapid and wide spread licensing mechanism or equivalent that will allow third parties to sell TOWERPOWER systems. Such a licensing mechanism was supposed to act as an accelerator of their return on investment in the European project;
● When making profit out of the TOWERPOWER project results, the SME Participants must have a market competitive advantage upon any other company granted by the SME-AGs to sell the TOWERPOWER system.
Use and dissemination of foreground
Implementation of the Foreground exploitation plan
Roles to play – SME-AG and SME individual claims
At the moment, no SME AGs and SME within the TowerPower consortium is keen on commercially exploit the TowerPower system because of the reasons explained above.
In general terms, seven main categories of stakeholders will be involved in the exploitation of the foreground:
1. TOWERPOWER component provider,
2. TOWERPOWER system integrator/distributor,
3. TOWERPOWER system installer/retailer,
4. Purchasing advisor, who will perform studies favourable to the implementation of TOWERPOWER systems,
5. Trainer qualified to deliver knowledge and know-how about the TOWERPOWER system,
6. Licensor,
7. Business Agent easing the development of a licensees’ network.
TowerPower’s SME AGs and SMEs are ready to transfer the foreground related to Components 1 , 2 and 3 to Capenergies in case it will decide to file a patent for the TowerPower integrated system.
Capenergies will then decide, in synergy with the SME-AG who initially own the different foregrounds, whom it wants to grant manufacturing license(s) for the integrated system to.
The licence(s) will be Non-exclusive.
The Component-manufacturing licensee(s) will bear all the industrialization costs, the counterpart being minimum purchase volumes guaranteed by the TOWERPOWER integrators’ community.
Whoever the chosen industrial partner(s) is, it/they will make a better price to the SME Participants than to any other TOWERPOWER system integrator.
The RTD Performers commit, through the signature of the Grant Agreement and the Consortium Agreement, to deliver all the knowledge and know-how required allowing Capenergies granting manufacturing licenses to others in case they wish to.
Sale of TOWERPOWER system to installers
Some SMEs in the network of TowerPower’s SME AGs have declared their interest in implementing the TOWERPOWER system in their wind turbines once the prototype will be fully commercially exploitable.
AEE got a letter of expression of interest in the TowerPower prototype from Esteyco. The company, which developed an innovative offshore wind turbine under the Elisa Project in the Canary Islands, has declared its interest in establishing commercial exploitation paths with the TowerPower Consortium.
Capenergies also got a letter of expression of interest in the TowerPower results and further development to come from NENUPHAR, the company which hosted the TowerPower prototype test.
In addition, SME-AGs have identified among its members several companies having a potential interest in the TowerPower integrated system. For instance, tower manufacturers need to implement Continuous Structural Monitoring systems with the aim of improve their products, so that they can supply the TowerPower system within their towers. Operators and Developers of Offshore Wind Farms need to monitor the behaviour of their assets to reduce maintenance costs. Some offshore service providers are offering complete maintenance solutions based on fault predictive models that require Continuous Structural Monitoring systems such as TowerPower.
Therefore, once the TowerPower integrated system will be marketable (after a further extensive testing phase), AEE, Cylsolar and Capenergies will look into finding companies that, within their networks, are interested in making Use of the Background and Foreground by packing (integrator) and distributing TOWERPOWER system.
TOWERPOWER system installers
Once the TowerPower integrated system will be marketable (after a further extensive testing phase), AEE, Cylsolar and Capenergies will look into finding companies that, within their networks, are interested in making use of the Background and Foreground by installing TOWERPOWER systems.
Purchasing advisors
Cylsolar intends to make Use of the Background and Foreground by selling sizing, design and implementation studies prior to installation of TOWERPOWER systems and/or by using their business network to ease the expansion of the licensing scheme.
Its return on investment in the TOWERPOWER project will come both from their direct study sales and from sales of TOWERPOWER systems. The second source of revenues will take the form of royalties on sales following their advice paid by SME-AGs upon presentation of evidences of their role in the deal conclusion with a client following their intervention, until their return on investment plus a bonus is ensured.
In some case, purchase advisors wish to develop also product-selling activities. The remuneration from royalties on study sales should be subject to clear-cut and auditable accounting of both activities.
Unfortunately, the project did not fully meet the expected results, the performance expectations and consequently their markets.
Indeed, the TowerPower prototype needs to be further tested on real structures or large-scale components, with and without faults, for a longer period (at least 6 months) and in different environmental conditions during the year 2018.
As long as an extensive result validation and well established reference/test base will not be available, the system will not be commercially exploitable for the SME AGs of the consortium.
Nevertheless, since the consortium recognises the added-value of the TowerPower system, even though the EU funding will be no longer available, it is willing to carry on working on making the TowerPower prototype exploitable.
Once the further testing phase has wholly proven the marketability of the prototype, Capenergies is willing to file a patent for the integrated system (in order to that, other SME AGs previously agreed to transfer their foreground to the Project coordinator), and consequently licensee its manufacturing and installation to chosen third parties, with a priority given to companies within AEE, Cylsolar and Capenergies’ networks. Consortium foresees that the integrated system will be ready for the market at Q3 2019.
List of Websites:
www.towerpower.eu
For any further information, please contact Paul Lucchese, Deputy Director of Capenergies by mail paul.lucchese@capenergies.fr