Have you ever wondered what people mean by the grid which they keep referring to every time they mention electric supply? A grid is nothing but a set of power suppliers and consumers connected through distribution and transmission lines. Nonetheless, most of the time, people refer to transmission lines as the grid. The National Grid of India is the high-voltage transmission system for electricity in India and operates at a frequency of 50 Hertz. The National Grid connects the power generating stations with the substations to meet the electricity demand throughout India.
The solar systems, based on their grid-connectivity, can be classified into 3 different categories- on-grid solar, off-grid solar and hybrid systems which are a combination of both. On-grid solar systems are the ones in which the solar plant in an individual or company's premises is directly connected to the utility grid. The solar power produced after being converted into AC current feeds the connected loads. The excess power at any point of time is transmitted back to the grid. This excess energy produced can be netted against the energy consumed from the grid. On-grid solar systems are most cost-effective and convenient to install. These are perfect systems for households as the cost incurred can be recovered easily through the excess power transmitted to the grid.
An off-grid solar system, in contrast, is a standalone solar system wherein the excess solar power produced from the panels is stored in a battery. These systems need costly specialized equipment to function. Hence, the sizes of such systems can get prohibitive as the costs exceed a certain limit. A hybrid system is a combination of both, i.e. a grid connected solar system, equipped with storage instruments.
An on-grid solar system might be apparently much more attractive than the off-grid system. Nevertheless, in an on-grid solar system, the solar power is produced only when the grid is available. The power supply gets completely cut-off in case of the grid outage. Hence, one needs to rely on back-ups such as DG sets for emergency power supply. The power shut down happens, mostly on account of safety and technical reasons. An off-grid system, however, can take care of the power supply even in the case of grid black-out.
On-grid solar systems are considered most suitable for individual households as the solar plant can be easily installed on the rooftop and the fixed cost can be recovered through savings made over the years. Hybrid systems are preferred by industrial and commercial houses who wish to optimize the savings through solar with the help of a battery storage system. A standalone off-grid system is mostly considered for installation in remote areas with limited grid connectivity. Hence, on-grid solar is one of the most popular means of solar in India given the cost-friendliness and ease of installation. Battery storage equipped hybrid systems have not been adopted on a widespread basis in India, despite their prevalence in developed countries such as US and UK.