A. What Is A Floating PV?
As we all would agree, solar power, especially the installation of floating solar power plants have gained significant popularity and acceptance in the energy sector. PV installations have proved to be cost efficient and carbon-light way of producing every from the solar radiation. Excluding the high initial investment, another big challenge for making PV installations more abundant is the need for land. While in large countries like Australia, the USA, or India availability of land is not a constraint, in many small countries, or islands like Japan, Malaysia, etc. availability of land is a major constraint.
Floating PVs are quite similar to normal PV installations, except for the fact that they are installed on a water body, thereby eliminating the need for land. Many times, even in large countries having plenty of lands available, the land in the vicinity of prime energy consumers (i.e. cities, industrial zones, etc.) is not available or highly unaffordable. Floating PV, also popularly known as ‘floatovoltaic’ is an attractive option at such places since it is independent of land availability. Especially at places where land is a roadblock, floating solar installations are a positive step for energy generation.
B. Why Is Floating PV A Good Idea?
As it is clear from the discussion above, adapting floating PV certainly makes sense, especially for places having a shortage of land. Apart from this, contrary to what many would believe, floating PVs are more efficient. To put it simply, the same installation consisting of the same number of solar panels, when installed in a water body, will generate more energy. The reason is the cooling effect caused by the water beneath.
As well all know, as the solar radiation increases, the module temperature also increases. The module temperature is in inverse relation with the module efficiency. So, in case of the conventional installations, as the radiation increases, the plant efficiency drops down. In a case of floating PV, water under the panels will keep them at the normal temperature as the heat would get dissipated through the water. Many studies claim that efficiency gain can result in as high as 12% increase in the energy generation. How would this heat and the consequent rise in the temperature affect the flora and fauna in the water body needs to be studied thoroughly first.
Another claimed benefit out of floating PVs is the reduced rate of evaporation. Researchers studying the evaporation rates from various water bodies have found them to be higher than anticipated. Water bodies like lakes, dams, canals, etc. are susceptible to water evaporation. Installing floating PVs will bring down the rate of evaporation thus leading to water savings.
From all these observations, one can conclude that solar PV is a good idea, given it has adverse effects on the ecosystem in which they are installed.
C. What Are The Advantages/Benefits Of Floating PV Installation?
From the above discussion, we can safely conclude on the following advantages of the floating PV installations:
- Higher Penetration: Since solar PVs are independent of the land availability, they will allow for deeper penetration of solar energy in cities as well as other locations.
- Higher Output: Since floating PV’s offer better efficiency than on land PV installations, one can expect higher energy outputs from the same capacity of the installation. This cooling effect will also prolong the life of the panels and will also put a cap on the long term degradation of panels due to exposure to heat.
- Movability: Floating panels are anchored at a particular location but they can be easily transported in the water body. The makes them ‘mobile’ unlike the fixed installations on the land.
- Reduced Rates Of Evaporation: Installing PV panels can bring down the evaporation losses.
Putting A Check On Algae Growth: Rampant and uncontrolled growth of algae in water bodies is a major concern faced globally. Installing PV setups in the water body can also put a check on the algae growth and can help keep the watered clean.
D. What Challenges Are Faced By Floating PV Installations?
One might wonder, in spite of so many advantages, why floating PVs are not a common sight yet. There are quite a few challenges and considerations which are preventing the floating PV installations from catching apace.
- Installation Costs: Since floating PVs need a floating framework and a provision for anchoring, the installations costs are high now. Many experts claim that once these systems become more popular and are installed widely, the costs will be at par or even lower than on-land installations due to the scale manufacturers would get.
- Environmental Considerations: Very few studies have been done which actually study the effect of floating PVs on the water bodies and ecosystem in them. Lack of this research and a firm policy could be the reason why companies are not investing heavily yet in this technology. As more clarity comes up, manufacturers and end users will start embracing this technology.
- Corrosion And Other Issues: Installations in water are more prone to corrosion and damages resulting out of it. The climate moves the water bodies is normally more humid and will call for materials which can withstand these conditions. Apart from metalwork, the wires, adhesives, sealants would also have to be capable of sustaining these effects. Installing PV in salt water (oceans) is even more challenging due to the highly corroding nature of the salty water.
- Impact On Drinking Water: Most of the water-bodies in our discussion are the water-bodies having potable water. The materials used in the construction of the PV panels and floating assembly should be non contaminating. Any negligence on this front can cause serious damage. This will also call for creating new standards and testing methodologies.
E. Generation Of Electricity Through Floating PV Modules?
How do floating PV modules actually generate electricity? Not much different than the conventional PV modules. The only difference is the fact that in the case of floating modules, batteries and other equipment is located on the shore. Usually, dead weights are used to anchor the plant at a particular location. These plants will have all other ancillary devices like solar tracking devices, weather monitoring stations, etc. for proper functioning.
Floating PV set-ups in India: An Overview
Here are some pointers which emphasize on the forward-looking approach of India towards the floating PV technology:
India’s so far the largest floating solar plant is located in Banasura Sagar reservoir in Wayanad, Kerala, Spread over 6,000 square meters, this is a 500 kW plant.
Vikram Solar commissioned 10kW floating solar power installation in Rajarhat, Kolkata. The Project was designed using 1kW fiberglass PV modules to produce a minimum of 14MWh of solar power annually.
Greenham Energy is deploying 24MW worth of floating capacity at an industrial reservoir in the city of Tuticorin, at the southern tip of the country.
NTPC has issued tenders in excess of 200 MW of grid-connected floating PV installations in the different parts of the country.
From the above discussion, it is evident that though floating solar technology has some unresolved challenges and faces some uncertainty, it is the technology which will emerge soon as a solution to our energy needs. Decreasing availability of land and reduced initial costs will further drive the growth of this technology.