Rooftop Solar Power for homes in Chennai, Tamilnadu

The open unused space on the roof in a house, villa or an apartment can be used wisely and productively to harvest solar energy both in forms of heat and light. This is referred to as rooftops solar which helps in providing greater savings on electricity bills and contribute to reduction of Greenhouse gases.

Types of Rooftop Solar power systems:

1.       Ongrid system: Operation of the Ongrid Rooftop system – Solar panels produce the DC power using the sun light. Produced DC power is converted into AC power by Ongrid Inverter. Converter AC power will be either supplied to our homes or exported to the Local Grid (TNEB) based upon our consumption of power.

 2.       Offgrid system: Operation of the Offgrid Rooftop system is also similar to the Ongrid system, but the difference is we can store the solar energy without exporting it. Offgrid systems store the power generated from solar in batteries and use it when needed. The power production will also be based on the usage and the storage space left in the battery during daytime.

3.       Hybrid System: Hybrid system, in a way, is the combination of the ongrid and Offgrid systems. The system stores power in batteries and exports the excess power to the local grid providing both bill saving and minimal power backup benefits. As on 2022, compared to the other two systems, Hybrid systems are not very popular due to their cost and reliability/warranty.

Cost and Savings of Rooftop Solar power System:

• Cost of the Residential rooftop system depends on the capacity and type of the system. Reaching the right company enlisted in TEDA and also analyzing the company’s past performance and their customer feedback makes your investment meaningful and fruitful.
• With their Technical capabilities, the right solar team with the right system and with quality components, will give you great and lasting benefits. To enjoy the benefits and return on investment, ensure choosing the right company with proper analysis in every possible way.
• Cost of the system also depends on the scope the system integrator takes up. Choosing  the right solar integrator or partner, who offer end-to-end scope, will result in smooth execution of the project.
• Ongrid systems will cost around Rs. 65-80/watt based on the brands, technology and scope. The price will reduce per watt as the system size increases. The perfectly designed Ongrid rooftop solar system will give Return on Investment (ROI) of 4 to 5 years.
• Offgrid systems can roughly cost around Rs. 95-110/watt based on the brands, technology and scope. The offgrid system can be optimized to provide power for 60-100% of a day & night usage, to the connected loads. This system is designed to provide reliable power supply independent of the grid focusing mainly on convenience for the user. For this system, the right way to calculate ROI is by the savings and the value of convenience given by the system.
• Hybrid systems can roughly cost around Rs. 110-130/watt. This system provides both bill saving and minimal power backup. But due to its higher capital cost, compared to ongrid and offgrid, the return of investment is least.

Installation of Rooftop Solar:

Area for Installation:

The space required for the installation of a solar system on the rooftop is calculated on the basic thumb rule of 80-100 sq. ft/KW with panels tilted to south based on the latitude. The space of the rooftop solar can be well optimized if the panels are mounted over a high raised structure which helps the user to use the area as shade or for gardening usage. Low raised structure might occupy roof area and might make the area unusable for other activities. But high raised structures are recommended where roof area is needed for multiple activities.

Installation duration:

Ongrid system: For the Residential ongrid rooftop system of 5KW (for example), installation can be done in 2-3 days (onsite) and installation time might increase depending on the system capacity and site complications (if any). After ongrid system installation, the net meter process is started by applying online, submission of hard copy of necessary documents etc. TANGEDCO personnel do site inspection and then, a net meter is installed. The process usually takes 25-45 days after system installation. But, depending on the availability with TNEB/TANGEDCO and other constraints, this can take much less or more time.

Offgrid system: The system installation takes 3-5 days (onsite) for completion for capacity of 5KW (for example) including the complete AC wiring scope. The system can be commissioned right after the installation, since it does not require any permission from the TNEB or it does not require any net meter.

Hybrid system: The system installation takes 4-6 days (onsite) for completion 5KW (for example) capacity and installation time might vary for different capacity. The net meter process takes 25-45 days from installation but till that time, the system works like an Offgrid system. On commissioning the system along with the net meter, the system performs as a hybrid.

Benefits of Rooftop solar:

• Bill Reduction: One can expect savings in electricity bill of about 60-100% depending on the type of system and the electricity usage. Usually, Ongrid systems give higher bill savings when the net-metering policy is applicable.
• Reliable power: Offgrid systems can give 24/7 power in addition to electricity bill savings. Even when EB/Grid power is OFF, the appliances connected to offgrid systems continue to be powered by solar. Note that Ongrid systems will be switched during EB power-cuts.
• Ease of Maintenance: Solar panels require cleaning (at least once in a month for less pollution areas and twice per month in areas prone to dust). For off grid and hybrid systems battery distilled water topping needs to be done only once in 3 months if installed with lead acid batteries. Also maintenance free batteries like VRLA gel batteries and lithium are available though at a much higher cost.
• Renewable: The fuel source for this system is sunlight, which is abundant and available for lifetime and more. Solar panels have a lifespan of 25 years which is very high. The power production does not involve fossil fuels which might get exhausted at a certain point in the near future. And solar energy is available daily and it’s purely renewable.
• Tariff increase: There might be high chances for the rise of per unit cost for power production and distribution by EB in upcoming years. Going solar helps you beat the inflation in tariff as the panels invested with capital amount might surely provide power free from sunlight and reduce the usage from grid/EB.
• Eco-friendly: Not using fossil fuels and no pollutants are involved in the complete process of energy production. So it is a completely eco-friendly way of producing electricity.
• Self Sufficiency: Solar is preferred by users who believe in self sufficiency and it helps users to go independent to a maximum level. Solar has proven its capability in highly remote areas and also succeeded in both urban and rural areas.