So you have been reading all the news around the rise and rise of solar energy. You realize it is a great investment both for you and the environment and have decided to finally go green yourself. Great. The first question likely to come to your mind is- ‘How big a solar system do I need?’ This blog post looks to answer this question.

The first step to deciding the capacity required by you is to determine which type of system you are looking to install- on-grid, off-grid or hybrid. In this post we will be focusing on on-grid systems, which are the most commonly installed systems.

The basic idea in an on-grid system is to install a system capacity which can generate as many units as you consume currently from the grid. This will help you offset your electricity bill by up to 90%+.

In India most regions get plenty of sunshine and typically power generation for a 1 kW system is around 120 units per month on an average. This of course varies by season. Bright clear skies in summer and autumn lead to generation of 140-150 units and monsoons lead to a drop to 50-60 units per kW.

To calculate the system size required by you, we simply look at your electricity bills of last 12 months and calculate the average units consumed. The system capacity then is just simply the average unit consumption divided by 120.

System capacity=Average units consumed/120

This system will meet your average electricity requirement and not the peak, as in case of summers. This explains why we say that solar can help you reduce your electricity bill by up to 90% and not 100%.

It is possible to install a system meeting your peak requirement (typically in summers when the ACs are running) and reduce your bill to zero. But this system will generate excess energy during the rest of the year which will go to waste and give you a lower financial return on your investment overall.

Please note that the approach given here is a simplified version of the optimization performed by us for an actual client. For any specific project we will look at the power generation data for the specific location and not the generic 120 units figure. Additionally, optimization algorithms are run on seasonal variations in your power consumption and generation to arrive at a capacity which maximizes your return on investment.

Reach out to Earth 47 team for a free site survey and see what capacity of solar system you require today.