The floating, canal-top, and canal-bank solar segments have been gaining traction as they help avoid land acquisition challenges and increase the output of power projects, despite their high upfront cost. Projections made by Wood Mackenzie suggest that the global floating solar demand will grow by an average of 22 per cent between 2019 and 2024. These floating photovoltaic (FPV) projects are preferred due to the very high prices of land, which makes it difficult for developers to acquire large tracts of land for ground-mounted solar projects. The land required per MW for a ground-mounted solar project is between 4 and 5 acres. However, by deploying projects over large reservoirs, lakes, ponds and canals, land can be preserved for other development activities.
When such projects are installed over hydroelectric plant reservoirs, they provide efficiency gains through better utilisation of the existing transmission infrastructure. Moreover, numerous studies suggest that the cooling impact of water on the back of modules improves their performance. Further, shading, civil work and grid interconnection costs are reduced. The presence of floating solar panels also reduces algae blooms and water loss via evaporation, thereby protecting water resources.
Despite the potential benefits of FPVs, the segment does face a few challenges. First, there are challenges related to anchoring and mooring the panels in place while considering water level variations, reservoir bed type and depth, extreme weather conditions such as high winds and waves. Due to this, the engineering and construction costs of FPVs are typically higher than those of ground-mounted solar projects. Second, there are safety concerns related to cable management and insulation testing, particularly when cables come into contact with water. Third, floating installations are vulnerable to moisture-related degradation and corrosion, particularly in harsh coastal environments. Fourth, there is a high risk of the water being contaminated by harmful substances. This may have an impact on the biodiversity in and around these areas. Fifth, these projects are expensive, because of the high costs of the imported materials required for setting up the necessary facilities. Moreover, maintenance activities are slightly more difficult in water than on land. Boats may be required to access solar plants, while divers may be required to inspect the anchoring and mooring systems.
Technology trends
A floating solar project uses the same electrical configuration as a ground-mounted system. But it is distinguished by the floating platform. Any type of solar array that floats on top of a body of water is known as an FPV array. Solar panels must be attached to a buoyant structure to keep them afloat on water. Unlike solar PV plants, pontoons are used in FPVs as the floating platforms upon which the solar panels are mounted. They are held in place by anchoring and mooring systems. Because of their critical role, the design of these anchoring and mooring systems is influenced by a number of factors, including wind load, float type, water depth and water level variation.
With the expansion of the floating solar segment, various types of floating platforms are becoming available in the market. Pure float configurations are the most common, globally. They have specially designed buoyant bodies that provide direct support to solar panels. Moreover, these floats have fewer metal parts and are easy to assemble and install. Pontoons with metal frames are another commonly deployed design. The metal frames are used to mount solar panels on pontoons, removing the need for specially designed floats. Further, to create a base for installing solar panels, the entire water surface can be covered with rubber mats or membranes fixed to floating rings. Other technologies include liquid solar arrays, high density polyethylene floating platforms, solar islands, floating grids, polyculture-based platforms and tracking-type floating solar systems.
Recent developments
There are many large FPV projects in the pipeline. Here are a few developments in the segment over the last couple of months:
- In January 2022, the Damodar Valley Corporation (DVC) estimated a floating solar potential of 2 GW across reservoirs at its Maithon, Panchet, Tilaiya and Konar dams in Jharkhand. The company has requested permission from the Ministry of New and Renewable Energy to build this capacity under the Ultra Mega Renewable Energy Power Parks scheme, and has already received approval for 990 MW. This capacity is expected to be built across three reservoirs in a joint venture (JV) with NTPC Renewable Energy Limited (NTPC REL). DVC has signed an agreement with NTPC REL to develop renewable energy power parks in and around its dam reservoirs.
- In the same month, Tusco Limited, a JV between the central government-owned hydropower company THDC India Limited and the Uttar Pradesh New and Renewable Energy Development Agency, invited bids for a consultant for floating solar power projects on various dam reservoirs in Uttar Pradesh. The scope of work includes preparing a pre-feasibility report and a detailed project report for the development of these projects.
- In May 2022, the winners of Rewa Ultra Mega Solar Limited’s (RUMSL) auction for the first phase of a 600 MW floating solar park in the Omkareshwar reservoir in Madhya Pradesh were declared. Amp Energy, NHDC and SJVN were awarded 100 MW each at the quoted tariffs of Rs 3.21 per kWh, Rs 3.22 per kWh and Rs 3.26 per kWh respectively. Then, in October 2022, SJVN won the Maharashtra State Power Generation Company’s auction to build a 105 MW floating solar project at the Erai Dam Solar Park in Maharashtra’s Chandrapur district, at a tariff of Rs 3.93 per kWh.
- In July 2022, India’s largest floating solar power project, the Ramagundam floating solar PV project, was commissioned in Telangana. NTPC declared the commercial operation of the final part, with a capacity of 20 MW out of the total 100 MW. The 100 MW FPV boasts of advanced technology and environment-friendly features. It was constructed at a cost of Rs 4.23 billion and spans over 500 acres of reservoir space. The site is divided into 40 blocks, each with 2.5 MW of capacity.
- In November 2022, Phase II of RUMSL’s auction for the floating solar park at the Omkareshwar reservoir in Madhya Pradesh was conducted. NTPC Renewable Energy won a capacity of 90 MW at Rs 3.69 per kWh, while SJVN Green Energy and Hinduja Renewables won 83 MW and 80 MW respectively, both quoting a tariff of Rs 3.70 per kWh.
- In December 2022, Gensol Engineering was declared the winner in an auction to develop 30 MW of floating solar projects at three thermal power plants across Jharkhand and West Bengal, with a bid of Rs 2.32 billion. The tender was issued by the Solar Energy Corporation of India in June 2022.
Outlook
The use of FPVs to harness solar power is likely to become more prominent, as the costs and technical challenges are expected to decrease as the technology advances. The Indian government is formulating fiscal measures to enable active domestic manufacturing of the necessary infrastructure for FPVs. The government is also consulting with states to identify stretches of waterbodies and reservoirs to set up floating solar projects.
As reported by the International Finance Corporation, there is significant room for growth in FPV power generation. Hydropower reservoirs alone cover over 250,000 square km of area around the world, which is sufficient to host floating solar capacity to produce 2.5 times the electricity produced by the underlying hydropower capacity. Combining hydropower generation with floating solar panels could produce promising results.
With India’s substantial renewable energy targets and land constraint issues, the potential of floating solar in the country should not be overlooked. While steps in this direction have been taken, more efforts should be directed towards identifying suitable waterbodies in each state to implement these projects.
Nikita Choubey