Ciel & Terre’s Anchoring Design Methodology corroborated by a FPV plant study
At Ciel & Terre, we engineer the Hydrelio® floating solar solution and design optimized floating PV plants with great care of each market and site’s specificities. Our main motivation is to offer highly reliable products and plants because their liability is the origin of the bankability of floating solar projects. To stick to this, we managed a study on one of our projects in Japan, hostile environment full of opportunities and the historical nation of floating solar.
Anchoring calculation methodology qualified by a case study
Ciel & Terre has collected data from Yukimine FPV plant, a Japanese project under operation since 2017, with the objective to correlate the wind load calculation methodology applied so far to the design of our floating solar plants. At the origin of this initiative is the will and commitment to continuous improvement.
ID card of the project:
- Yukimine, Tokushima prefecture, Japan
- Irrigation pond – 32 anchors
- 6 MWp – 5808 panels of 60 cells
- Achieved in 2017
Yukimine monitoring system is quite complete. It includes the necessary equipment to link the global loads applied on the plant to the wind: anemometers at different height levels to get wind speed data, weathervanes to get the direction from which the wind is blowing, load sensors to evaluate the mooring line tensions generated by the wind and an ultrasonic sensor to gauge the water level state. In total, 77 sensors of different kind have been installed and harnessed.
Monitoring equipment highlights below:
6m height anemometer
0.6m height anemometer
Load sensor
With the equipment installed and data collected, Ciel & Terre is able to link the plant global effective load to the theorical aerodynamic expression (K x V²)[1] . The K factor is a function of the wind direction, same as CTI drag, drift and lift factors obtained through CFD[2]. The K polar result graph[3], as presented below, indicates how the wind loads spread on the floating PV plant as per its cardinal points. The outcome of the site monitoring analysis shows that the monitoring installation protocol is satisfying to match with the theoretical approach. It is actually reliable for aerodynamic factor analysis and corroborates Ciel & Terre anchoring design methodology.
Hydrelio® plants by Ciel & Terre can resist harsh conditions
Ciel & Terre has collected data from Yukimine FPV plant, a Japanese project under operation since 2017, with the objective to correlate the wind load calculation methodology applied so far to the design of our floating solar plants. At the origin of this initiative is the will and commitment to continuous improvement.
In the South East Pacific region, typhoons are relatively typical climatic events and Japan stands for no exception. Since 1951, the country has undergone more than 425 such events[4]. Yet, Ciel & Terre succeed from pioneering on floating solar in this harsh area. The Japanese nation was indeed the early adopter of this technological innovation when the company’s floating solar adventure started about 10 years ago. We count there more than 115 floating PV plants equivalent to more than 180 MWp.
The Japanese floating PV project monitored in the study is located in an area which was hit by 2 typhoons (#20 and #21). These 2 typhoons, respectively Cinamon and Jebi (the latter broke wind record and led to temporary close of Kansai airport[5]), had no impact on the Hydrelio® floating PV plant installed though it was located on their paths.
Floating PV plants’ monitoring: why monitor and how to do it
At Ciel & Terre, we highly regard Tests and Simulations and have dedicated teams. They put their complementary expertise at the service of product innovation and the achievement of projects. They work on the composition, the feeding and the development of numerical simulation models (including Anchoring, Mechanics, and Hydrodynamics and Aerodynamics as CFD fields of expertise) and correlation.
Indeed, numerical simulation, enabled by expert software and data inputs (meteorological, from the project track-records, raw material behaviour and product characteristics), does not walk alone. Physical correlation comes in pair. This is made possible thanks to data issued from our real-scale test bed measurements and monitoring of full-scale projects. The aim is to calibrate numerical models and design methodology with onsite reality. Consequently, it ensures the reliability and bankability of the floating PV projects and CTI design processes.
The company’s methodology has also been approved by Bureau Veritas Rules and Regulations NR 493 in spring 2020 and certified in line with DNV JIP Recommended Practice about floating solar projects’ design (DNVGL-RP-0584) in spring 2021[6].
[1] Original equation: 1/2 x p x S x C x V2
[2] Computational Fluid Dynamics: analysis of fluid flows using numerical solution methods. Using CFD, you are able to analyse complex problems involving fluid-fluid, fluid-solid or fluid-gas interaction. Source: https://www.femto.eu/stories/what-is-cfd/
[3] Linear regression has been applied to the 24 graphs F = f(V2) generated from this study to get equivalent wind direction K aerodynamic factor.
[4] Source: http://agora.ex.nii.ac.jp/digital-typhoon/disaster/landfall-full/index.html.en
[5] More info: https://qz.com/1378242/typhoon-jebi-photos-of-japans-most-powerful-storm-in-25-years/
[6] More information in this article: RECOMMENDED PRACTICE DNVGL-RP-0584: STANDARDIZE FLOATING SOLAR TO EASE ITS DEVELOPMENT, https://www.ciel-et-terre.net/recommended-practice-dnvgl-rp-0584-standardize-floating-solar-to-ease-its-development/
