The Government of India has set an ambitious target of 500 Giga Watts (GW) of non-fossil fuel-based electricity generation capacity by 2030, with a significant portion of contribution from solar, Floating Solar PV (FPV) is identified by MNRE as one of the key applications. GIZ is supporting MNRE under the Indo-German Solar Energy Partnership-Innovative New Solar Areas (IGSP IN-Solar). GIZ has engaged Deloitte, IIT Madras, IIT Roorkee for “Development of Guidelines and a Centre of Excellence for Floating Solar PV in India.”
Mainly to develop comprehensive FPV guidelines, spearhead FPV advancement in India, review global standards for floating PV system, do gap analysis, come up with recommendations for India, draw a road map for the centre for Excellence besides Engagement with stakeholders throughout the development of CoE to foster FPV ecosystem.
Just to recapitulate the advantages of FPV are many refer: https://www.electricalindia.in/multiple-advantages-of-floating-solar-pv/. At a glance:
Efficient Land Use – Utilizes water surfaces, preserving land for agriculture and development.
Higher Energy Efficiency – Water cooling reduces panel temperature, improving performance.
Reduced Water Evaporation – Limits evaporation, conserving water in reservoirs and lakes.
Improved Water Quality – Reduces algae growth by blocking sunlight on the water surface.
Lower Land Costs – Avoids expensive land acquisition, reducing overall project costs.
Lower Environmental Impact – No deforestation or land degradation compared to ground-based solar.
Synergy with Hydropower – Can be installed on hydroelectric reservoirs for combined power generation.
Increased Energy Yield – Water reflection enhances sunlight absorption, boosting efficiency.
Flexibility and Scalability – Easily expandable and adaptable to various water bodies.
Reduced Dust and Maintenance – Less dust accumulation lowers cleaning and maintenance costs.
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But most notably water saving to the extent of billions of cubic metres in a water stressed country with 18% of the population having only 4% of the fresh water sources, I hope would attract the attention of Niti Ayog, Central Water Commission and Ministry of Jal Shakti, at a time capital-intensive large-scale sewage water treatment and desalination is on the anvil to make water available.
It is only a matter of time that with economies of scale and advance in mooring and anchoring FPV would be cheaper than ground mounted solar energy plants. The potential of marine floating Solar (in hybrid mode with tidal in areas of hightide) yielding green hydrogen for the hard to abate transport sector makes it more attractive. FPV is an appropriate technology and a game changer in the energy transition along with waste to energy.
Site Selection
Is it possible to define a range for surface coverage percentages of water bodies based on their type or use? In Germany the limit is set at 15%. Research papers suggest a preferred surface coverage percentage between 10% and 40%. However, in water bodies where maintaining water quality is not a concern and there is no aquatic ecosystem, surface coverage of up to 70-80% is feasible.
Is there a defined range of water level fluctuations that can guide the selection of anchoring types or other design modifications to ensure the FPV system can withstand these water level fluctuations? Is it possible to install FPV plants in water bodies where water levels can drop to less than 1meter based on data from the past 15-20 years? If so, what type of floating structure is preferred in such cases?
Currently, designed systems withstand wind speeds of 44-50 m/s, based on the gust values specified in IS 875 (Part 3), which already incorporates a conservative design approach. Are there any other design modifications that can help FPV systems withstand higher wind speeds? And beyond wave barriers what would withstand high wave heights.
Factors such as solar irradiance, ambient temperature, humidity, and water temperature significantly affect the performance of FPV systems. Are there any additional parameters that need to be tracked to monitor the operation & performance of FPV plants?
Parameters Monitoring
To reduce uncertainty in FPV projects, it is preferred to monitor climatic conditions using a meteorological measurement station near the FPV installation site. Factors such as solar irradiance, ambient temperature, humidity, and water temperature significantly affect the performance of FPV systems. Are there any additional parameters that need to be tracked to monitor the operation & performance of FPV plants?
Design Criteria for Floating Structures
Is there a specific set of criteria for selecting the type of floating structure based on site conditions and functional requirements? There are different types of floating structures available for Floating Photovoltaic (FPV) systems, such as pure float, modular raft, and membranes, each with its own benefits and challenges. For example, modular rafts can better withstand high wind speeds and wave heights compared to pure floats, but pure floats offer better resistance against corrosion.
Additionally, along with steel and HDPE, ferro cement can also be used for floating platforms. What are the advantages of using ferrocement over HDPE and steel for making floating platforms? Apart from maintaining a lower angle of tilt and using wave breakers, are there any other design modifications required in floating structures to ensure the structural integrity and stability of FPV systems under extreme environmental conditions?
Stakeholder discussions indicate that no corrosion has been observed in installed FPV systems in India so far. However, what measures should be taken during the design and installation phases to prevent corrosion? Are there specific coatings recommended for preventing corrosion in floating structures, and if so, what are their specifications?
What technical standards are considered when designing and selecting floating structures in India?
Based on secondary research, anchor selection for FPV systems depends on water depth and waterbed type. For shallow depths (<10m), screw anchors are ideal. For medium depths (10-50m), use gravity anchors up to 20m and helical anchors up to 50m. For deep depths (>50m), drag anchors are best. In sandy waterbeds, screw anchors provide good holding power. Helical anchors are suitable for muddy or silty waterbeds due to their vertical load resistance. Gravity anchors work well in rocky waterbeds but are not recommended for loose gravel and uneven slopes. Is there any other parameter that can be taken into consideration while choosing the anchor type?
Design Criteria for Mooring and Anchoring
Factors that contribute to deciding the mooring type, and how do they influence the decision? According to stakeholder consultations, elastic mooring is preferred in cases of extreme water level variation, while taut mooring lines are suitable for low water level variation.
Are there specific criteria for selecting the material composition in mooring line based on site conditions? According to stakeholder consultations, polyester and wire rope are preferred materials for mooring systems. Polyester offers stretchability for better load distribution, while wire rope provides greater durability but lacks stretch. To optimize performance, a combination of both materials is used.
PV modules used in FPV systems are exposed to high humidity, saline conditions, mechanical stress, water splashing, condensation, electrical issues, and potential induced degradation. Based on secondary research, it is observed that glass-glass modules offer better resistance to harsh conditions and enhanced protection. Does the use of glass-glass modules increase resistance to these conditions? If so, how do dual glass modules withstand these environmental challenges?
Design Criteria for Electrical Systems
Based on stakeholder consultation, it is observed that type of inverter i.e., central or string inverter to be chosen based on size of project, distance from shore and considering LCOE. Are there any other factors that need to be considered while choose type of inverter and electrical equipment layout.
Design Criteria for Material Storage
What are the best practices for material storage, considering that storing materials far from the site can lead to transportation challenges, while storing them near the site may risk damage during extreme conditions? For example, at Omkareshwar Dam, materials stored on-site were damaged during a flood.
Conclusion
While the challenges to FPV design are increasingly catered to through Industry-academia interaction, FPV tariffs shall come at par or even below ground mounted solar to deliver RE with water.
Dr. Bibhu Prasad Rath is a highly experienced Additional General Manager with 33 years of experience in the power sector, specializing in Energy, Environment, and Economics, robust foundation in operations, design, procurement, feasibility, policy formulation, investment decisions, and carbon credits. Currently, after completing a 13-month stint at the Ministry of Power, GOI he is heading the New Projects Group in the Engineering division of NTPC. He obtained a Ph.D. in Business Administration from Aligarh Muslim University and published numerous papers in various journals and conferences on actionable issues of climate change, sustainability, heartfulness, decision making and leadership.
