FLOATING SOLAR PHOTOVOLTAICS

Most current Photo Voltaic solar systems are typically designed for land-based applications and require large tracts of land which could otherwise be used for agriculture, housing or industrial construction. The Floating Solar Photo Voltaic (FSPV) market is a new growing market. In general, the cost of the water surface is much lower than the cost of land.

Solar panels installed on land face reduction of yield, as the land gets heated up. When such panels are installed on a floating platform, the heating problem is solved to a great extent. A floating solar power station would prove to be a revolutionary step as it could solve the perennial problem of land. 

A normal FSPV can be installed on all types of water bodies like lakes, saltwater lakes, reservoirs, irrigation ponds, small water sources, dams, rivers etc. Applications can also be extended to Water retention pond, Drinking water pond, Aquaculture pond, Water treatment reservoir, Hydroelectric Dam, Industrial water pond, Quarry lake etc

Environmental benefits

• Significantly reducing water evaporation. Conserves water and preserves existing ecosystems. The system shades the water and can reduce evaporation by up to 70%.
• The systems can also improve water quality. As water bodies are exposed to the sun, photosynthesis promotes the growth of organic matter, including algae. By shading the water, algae growth is reduced, minimizing the associated treatment and labour costs.
• Limits erosion or reservoir embankments by reducing wave action.
• All materials can be recycled.
• Low environmental impact: no excavation work, no impact on water quality.
• Reduced erosion of reservoir embankments by reducing waves.

Social benefits

• Preserves valuable land and water for agriculture and other uses.  Availability of land is a big problem. This is one of the primary reasons why Japan has been interested in the floating PV technology. If one is planning to put floating PV in dam reservoirs, it can make better use of the reservoir surface, which is in any way lying idle.
• Rehabilitates contaminated areas generating clean energy.
• Compatible with recreational activities.
• Positive aesthetics.

Economical benefits

• Converts unused land areas to profitable areas.
• No large land requirement, hence no cost for time-consuming statutory approvals, land acquisition and development.
• Since modules are installed in close proximity to water, hence the cooling effect increases the energy generation.
• Typically areas with high solar energy potential tend to be dusty and arid. So in comparison to their ground mounted counterparts, floating PV system not only have to perform in a low dust environment, they can always use a sprinkler to bathe themselves clean.
• In terms of installation speed per kW, it’s seven times faster than a rooftop installation.
• Return on investment boosted from the low lease price and installation costs
• Standardised equipment to ensure low production cost and competitive system prices
• FSPV can support distributed generation & micro-grids, using local water bodies. 
• No tools or heavy equipment needed.

FSPV in India is in its nascent stage. The first floating solar plant to be set up inside a reservoir in the country is a 10-kilowatt-capacity plant, spread over 1,200 sq ft installed on concrete floaters with hollow insides.  Kerala’s first floating solar plant at the largest earthen dam Banasura Sagar reservoir in Wayanad was put in service during January 2016. The platform can carry 45 tonnes and the power generated was fed to the KSEB grid through cables drawn through the reservoir bed. 

A demonstration plant set up at NTPC, Kayamkulam used floaters made of a Non-corrosive material, for fitting the solar panels. These were developed by NTPC Energy Technology Research Alliance (NETRA), the research wing of NTPC, in collaboration with the Central Institute of Plastics Engineering & Technology (CIPET)

The largest FSPV venture in the country, 500 kW,  was commissioned on December 4, 2017, by KSEBL at Banasurasagar, spending Rs 9.25 crore on the project. The plant will generate 7.5 million lakh units of power a year which has been installed on 18 unique and indigenously developed floating structures. Besides, 500 KVA (Kilo volt-ampere) transformer, 17 inverters, each with 30-KW capacity, Supervisory Control and Data Acquisition (SCADA) system to control and monitor power generation and a unique anchoring system, imported from Sweden, to stabilize the plant on water have also been installed on board.

FSPV System Components

Except for the float design, the tracking mechanism and the internal cabling, all other components are same as those used in conventional ground-based solar PV installations. They are generally, easy to install, dismantle & recycle, easy to adapt to any electrical configuration, scalable from low to high power generation, no tools/no heavy equipment needed.

Advantages

There are several distinct advantages of floating solar PV plants:

1. Prevents water evaporation by sun and wind effect up to 70%,  approximate saving of 5.0 Mn Ltrs of water per MW per year which saves the cost of sourcing and pumping needs of make-up water.
2. Sunlight reflection from water further enhances the radiations level on the solar arrays, boosting the generation.
3. Maintenance cost is minimized since soiling is drastically reduced in water.
4. Modular structure leads to faster installation, and size can be scaled up quickly in a short time.
5. Algae growth is greatly reduced as less sunlight reaches to the water.
6. The inactive water surface is used to produce clean energy.
7. Studies have shown that if the rear surface of solar panels is kept cooler, then their ability to generate power goes up by 11%.

Challenges

The challenges posed by such installations are :

1. Mechanical damages to the floats caused externally, causing it to sink.       
2. Waterbirds could be attracted to the project by virtue of its being on the water? Could they nest, leave droppings or otherwise cause problems?
3. What concerns are relevant in the case of freshwater as opposed to saltwater/seawater?
4. What is the risk of power loss in PV modules due to microcracks caused by vibrations due to wind, waves and external forces?
5. The open structure of the system should ensure adequate aeration of the water as well as natural light penetration and presents no hazard to underwater life.

For more details: Soura Natural Energy Solutions