Ways to Soar High With Floating Solar Plants

During recent years, nations facing a constraint of land for solar installations have shifted their focus towards an aquatic solution – floating solar islands. By positioning solar panels on floating platforms in bodies of water, it liberates valuable land. Thanks to the cooling effects of water, these panels can perform effectively even in high temperatures, ensuring efficient operation even under challenging conditions. Moreover, the shading provided by the floating panels reduces evaporation, thereby aiding in water conservation for the reservoirs where they are installed. Currently, countries like China, Japan, Taiwan, and South Korea have set up floating solar installations with a combined capacity of 2,400 MW¹, sufficient to power around 240,000 households. The appealing features of floating solar farms have attracted investments from various countries including, the Netherlands, France, Singapore, India, Vietnam, Thailand, and Sri Lanka, with an estimated value of US$380 million.

Although the prominence of floating solar plants is on the rise within the green-energy sector, its greatest asset can also be its major liability. The vulnerability of floating solar systems to natural phenomena such as rainstorms, hurricanes, and extreme heat, which have become more frequent, is impeding their advancement. Events like tidal waves, commonly occurring during hurricanes, often lead to irreversible damages to the system’s floats, cables, and wires. A major incident took place during the 2019 typhoon in Japan, where intense waves resulted in the solar panels clustering together and causing a fire that wrecked the offshore power plant. This event has directed attention towards the construction methodologies used in floating solar installations. Apart from unpredictable natural calamities, regular environmental conditions around water bodies, including humidity, strong winds, and salinity, can deteriorate the lifespan of onboard electronic equipment, and subsequently, the plant itself. Therefore, the focus areas predominantly revolve around the durability of the equipment and the construction techniques employed when establishing a floating solar installation.

Another significant challenge is the daily upkeep of the plant assets. The offshore floating systems pose more maintenance challenges compared to their onshore counterparts solely due to accessibility issues. While the latter can be easily accessed by land vehicles, the former necessitates the use of boats, making daily maintenance operations quite arduous. With the evolution of technology, solar plants are scaling up in size, rendering this already demanding task close to unmanageable, with potentially severe consequences. For instance, the floating solar plant in Anhui Province, China, is situated in a water-filled coal mine pit hosting 160,000 solar panels. Maintenance personnel rely on paddle boats to carry out equipment repairs and pond cleaning on a daily basis. When a typhoon strikes, bringing heavy rainfall and tidal waves, the lives of workers are perilously endangered.

Traditionally, power plants have heavily banked on routine site inspections, which require deploying staff for daily checks on each piece of equipment. As a result, these inspections become fixed costs irrespective of the equipment’s condition. Time is often wasted on routinary checks of functioning devices and, when a breakdown does occur, even more time is consumed traveling between the shore and the deployment site to fetch the necessary repair tools. A common scenario is the unexpected power deficiency even on sunny days. Identifying the cause of malfunction and its location isn’t straightforward from the onshore control center, prompting inspectors to investigate each floating module until the issue is pinpointed. This process mirrors searching for a needle in a haystack, tedious and time-consuming. Furthermore, limited transport options coupled with other factors like climate conditions and water flow direction make inspections physically demanding and hazardous, ultimately reducing maintenance efficiency.

Recent years have witnessed the adoption of the Internet of Things (IIoT) in floating solar installations to combat the maintenance challenges. Being one of the frontrunners in providing IIoT-based solutions, Moxa has firsthand experience in leveraging IIoT to enhance operations and maintenance within green-energy projects. Over the past decade, Moxa has collaborated with GreenPowerMonitor, a DNV GL company, a globally recognized independent software vendor, across more than 2,000 solar power plants worldwide. The IIoT connectivity solution can establish a framework enabling owners to monitor power generation and equipment status through a real-time SCADA system. It can also conduct maintenance checks on devices post-malfunction. The SCADA platform can be configured to automatically trigger an alarm and generate a maintenance task within the system, which can then be monitored by the owner. Equipped with knowledge regarding the cause and location of malfunction, maintenance personnel can promptly repair devices by being at the right spot with the appropriate tools at the right moment. Experience indicates that the efficiency of a power station equipped with a centralized monitoring and maintenance system can increase by at least 20% compared to those lacking such a system.

Furthermore, the data gathered through IIoT can be utilized to preemptively ascertain the likelihood of equipment failure near water bodies by analyzing its performance under various scenarios. Innovative Machine Learning algorithms can be implemented to enable owners to execute predictive maintenance on their equipment, thereby averting permanent damage. For example, when a device’s temperature rises owing to increased humidity, the device’s lifespan could significantly decrease. Insights derived from Machine Learning algorithms can empower the owner with predictive information on their devices. Consequently, when a specific humidity threshold is about to be reached, a warning can be issued, or appropriate measures can be automatically initiated.

IIoT’s predictive capabilities can also be harnessed in green energy forecasting and grid-connected technology to procure real-time predictions and efficiently regulate power generation from grid-connected renewable energy sources. To embark on this transformation, a resilient data network for transferring data from remote offshore equipment to the onshore control center is imperative. GPM and Moxa have devised a connectivity backup solution to prevent complete network disconnection in such scenarios. This solution ensures data transmission through a backup channel within 20 milliseconds while the network restoration process is underway, in contrast to the industry standard of 80 milliseconds, ensuring a continuous flow of information.

With the advancements in solar technology, enhanced construction techniques, and IIoT applications, floating solar power installations are well-positioned to transcend the existing restrictions and limitations that have been impeding their progress.

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References:
1.    REN21, Renewables 2020 Global Status Report, Paris, REN21 Secretariat.