8 interesting things to know about your solar panel

Solar panels are the heart of any rooftop solar system. They are made up of photovoltaic cells arranged in arrays and convert sunlight falling on them into electricity.

Types of solar PV cells

Depending on how the cell manufacturing is done, there are 4 types of PV cells.

Monocrystalline PV cell

These cells are manufactured using a cell-growing technique called the Czochralski method. In this method, pure silicon is grown into bars and thin wafers are sliced from this single (mono) bar. The cells are rounded off at the edges, which helps in reducing the gaps between adjacent cells. Since the wafers are made up of pure silicon, these panels have a distinct black or dark blue colour. This method is expensive and also there is wastage of silicon. However, monocrystalline cells are of premium quality and have the best efficiency. This wastage is further used to make other PV cells like polycrystalline cells.

Polycrystalline PV cells

As the name suggests, these cells are made from several different silicon crystals. The silicon waste is melted and poured into square moulds and hence these are square-shaped. They are less efficient and have low heat tolerance. This means, that more cells would be required as compared to monocrystalline cells and hence more space is required for the same output generation.

Source: https://ases.org/monocrystalline-vs-polycrystalline-solar-panels/

Thin film PV cells

These solar panels are manufactured by depositing photovoltaic materials like Amorphous silicon (a-Si), copper indium gallium selenide (CIGS) and cadmium telluride (CdTe) on solid surfaces such as glass, metal or plastic. These are lightweight and easy to install as well as easy to manufacture. They are cheaper than mono and poly cell types as less material is required to manufacture them. These have lower life and need more installation space and are hence suitable for applications where space is not a constraint.

Source: https://news.energysage.com/types-of-thin-film-solar-panels/

Passivated Emitter and Rear Cell (PERC)

PERC solar cells have an extra (passivation) layer within the back side of the cell. This layer can be added to mono as well as poly PV cells. This extra layer allows some of the sun’s rays to reflect back into the solar cell, giving them another opportunity to be turned into energy. This results in the system achieving higher efficiencies. These are ideal for limited space. They can be produced using the same manufacturing equipment and are suitable for applications where space is a constraint.

Solar panel technologies

Half cut Panels

In this technology, every cell is cut in half which means that the solar panel will have many more cells as compared to uncut cells. To give an idea, a traditional monocrystalline panel has 60 to 72 cells and half cut solar panel will have double the number of cells, meaning 120 to 144 cells. The solar panel itself is divided into two parts- upper and lower. In case the parts, fall under shadow the other part will still work, thus generating power which would otherwise not be possible. This technology offers several advantages - higher wattage, reduce power loss due to reduced internal resistance and reduced hot spots as less current is generated from each cell and there are more cells to spread the heat generated.

Image credits: https://www.solarismypassion.com/blog-detail/Half-Cut-Solar-Module-An-Overview

Bifacial panels

This technology allows electricity generation from both sides of the panel making it more energy efficient. However, these will make sense in places where the reflected light can reach the backside of the solar panel. If the installation is on a pergola or a ground-mounted system, this technology might make sense. In short, the more reflective the environment (like heavy snowfall areas or a sand beach) around the panel, the more energy it will generate.

Price of solar panels

The price of solar panels in India has seen a 90% price reduction in the last 10 years.

The average price of monocrystalline, polycrystalline and mono PERC is Rs. 30 per watt, Rs. 24 per watt and Rs. 26 per watt respectively.

The price varies as per the geography, the efficiency of the panel and the size of the system to be installed.

Efficiency and life of panels

Maintenance

Solar panels are low-maintenance assets. They need to be cleaned with a non-abrasive sponge, mild soap and water to get rid of dust, bird droppings and other foreign material. The maintenance is even lower if the installation has a tilt as rainwater washed away most of the dirt naturally. It is recommended to get your panels cleaned professionally, about 2 -4 times a year. You can schedule your cleaning when you see a drop in your output using the monitoring application.

Manufacturers in India

Source: PV module intelligence brief Q3, 2022 by Bridge to India (https://bridgetoindia.com/report/india-pv-module-intelligence-brief-q3-2022/ )

Gujarat-based Waaree Energies Ltd is the leading manufacturer of solar panels in the country, followed by Adani, Kolkata-based Vikram Solar and Haryana-based Saatvik Green Energy.

Leading manufacturing countries around the globe

China leads the world’s solar supply panel supply chain by contributing to at least 75% of every single key stage of solar photovoltaic panel manufacturing and processing. In second place stands Vietnam which contributed about 8% and then South Korea about 5%.

Government incentives for solar panels

Production-linked incentives (PLI) for manufacturers

In September 2022, the Union Ministry of New and Renewable Energy (MNRE) launched ₹19,500-crore scheme to incentivise the manufacturing of domestic solar cell modules. This was the second phase of PIL, in the first phase, a budget of 4500 crores was allocated in the Union Budget. Bidders for projects would be given PIL to set up and run manufacturing facilities that will span the entire production cycle of modules from making the polysilicon cells, ingots, wafers and panels to assembling modules that are used to produce electricity. They can bid for any one of the following three baskets:

1. The manufacturing of polysilicon, wafers, cells and modules or a fully integrated thin-film module plant (10GW maximum bid and INR 12 billion of funding available).

2. The manufacturing of ingots and wafers as well as solar cells and modules (6GW maximum bid and INR 4.5 billion of funding available).

3. The manufacturing of solar cells and modules (6GW maximum bid and INR 3 billion of funding available).

If any funding is left over, it will be distributed across the remaining categories, starting with the most integrated category (i.e. number 1 in the example above and moving down). However, the maximum capacity awarded will be just 50% of the capacity to be set up under the applicant’s bid, meaning the Indian government will support half the manufacturing base, with the applicant expected to build out the second half on its own. The PLI will be disbursed to firms after they set up their manufacturing units and the money disbursed over five years.

The government also imposed a 40% basic customs duty (BCD) on solar modules and 25% on solar cells from 1 April 2022, in a move that would make imports costlier and encourage local manufacturing.

Subsidy for residential rooftop solar

The central financial assistance (or Subsidy) is available only for grid-connected solar rooftop projects in the residential sector installed through empanelled vendors only. Central Financial Assistance (CFA) for the Residential sector is given below:

The government has provided maximum subsidy for system sizes of up to 3KW, making it a viable option for households who have an average monthly electricity bill of INR 3000. To know more about the cost of a 3KW rooftop solar system, click here.

The current policy environment and the falling cost of the components make rooftop solar a viable option for your home. The return on investment for a rooftop solar system is better than bank fixed deposit rates and it is a highly safe, risk-free investment with guaranteed returns.

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