Today, within the larger ecosystem of renewable energy sources, solar rooftops not only offer an economical and clean alternative to conventional energy sources but also delivers reliability i.e., that independence from grid-based energy sources that are prone to load-shedding and other hindrances to a consistent quality of service. Solar rooftops that is looped back into the grid also helps consumers turn into micro-generators of power and thus lower the monthly energy bill consistently.
Not counting the potential savings by selling excess power to the grid, a typical residential rooftop solar can save up to Rs 50,000 per kw a year or around Rs 12.5 lakh with a 25-year lifetime of the installation.
Rooftop solar has been around in India for some time now with consumers in all four major segments — commercial, industrial, residential and public sector buildings. In fact, residents in large cities like Bangalore and Delhi (and in several cities that can have severe winters) have for long used rooftop solar to heat water at a relatively lower cost.
Despite its inherent cost and environmental benefits, adoption of rooftop solar has been low in India. There are two main reasons for this — one the lack of adequate knowledge about the benefits of rooftop solar and two, the initial cost of installation. Thanks to the changing profile of mass media, with social media playing a major role in influencing consumer behaviour, the first challenge is already being addressed effectively, albeit at a pace slower than it ought to be. However, the initial (capital) cost of rooftop solar for the end consumer is still not within the reach of a larger section of the country. The broad demographics of rooftop solar consumers highlights this better. Only 15% of the 4,375 MW of installed rooftop solar in the country are residential consumers, who are typically more conscious of the initial cost than their counterparts in the commercial, industrial and public sector groups.
The initial cost of rooftop solar varies depends on how much of the energy one would like to generate. Consumers can calculate the cost by the following method:
A. Calculate the approximate load (in watts) for a day
B. Divide A. by 8 i.e. average no. of hours of sunlight in a day
C. Multiply B. by INR 110
For example, an 1800 watts a day usage will need solar panels that can produce 14,400 watts. The cost will be approximately Rs 15,84,000.
Rooftop solar basically comes in three formats — grid-based, off-grid and hybrid. In the grid-based system, the rooftop consumers are connected to the larger grid that is owned by the local utility. The primary source of power is from the rooftop system and the grid power source is used as a backup, should the rooftop solar fail to generate enough power (usually due to poor sunlight). Off-grid as the name suggests is a standalone system where storage batteries are needed to keep the power flow steady throughout the day. So, energy produced during the day, while is consumed, is also saved in batteries and discharged after the sun has set. One of the important and useful application of these off-grid solar systems is providing access to electricity to underserved people by installing solar based micro-grids with battery storage. Storage batteries come in various types such as Lead-Acid (Advanced Lead-Acid and Lead-Acid Carbon) Batteries, Sodium-Nickel-Chloride Batteries, Lithium-Ion Batteries, Nickel-cadmium, and nickel-metal hydride. Lead-Acid and Lithium-Ion batteries are quite common today, with the latter enjoying the advantages of long cycle life and high recharge rates. These standalone systems help in eliminating the requirement of investing in transmission infrastructure along with minimizing the transmission losses.
Innovations in Rooftop Solar
As solar power moves from the fringes to the mainstream, the costs of products like rooftop solar is also bound to come down. Some innovative financing schemes are also available in the market that allows customization depending on the type of user and what they can afford. The universal electrification project initiated by the government of India along with emerging innovations in rooftop solar products such as do-it-yourself solar kits is bringing more consumers closer to energy independence. The rising environmental concern that is deflecting consumers away from conventional energy sources has only made the market more conducive to rooftop solar in India.
Source : – Rooftop solar power: A bright and clean idea on our terrace