Solar panels absorb the sun's energy throughout the day and convert it into direct current (DC) electricity. Most homes and businesses run on alternating current (AC) electricity, so the DC electricity is then passed through an inverter to convert it to usable AC electricity. At that point, you either use the electricity in your house or send it back to the electric grid.
In a rooftop solar power system, the solar panels are installed on the roof of any residential, commercial, institutional and industrial buildings. This systems may be one of the following types
(i) rooftop solar power system with power storage facility using battery, and
(ii) grid connected rooftop solar power system.
Staying “on the grid” means to stay connected to your utility company that provides you electricity. This could be your local electricity distributor. MAHADISCOM for example. Going “off-grid” means to sever all connections to your utility company. For this to happen you need to be confident that you have solar system set up that can produce enough energy to provide all of your requirements. You would also need to install solar batteries to store energy that can be used at night. Going “off-grid” is generally not recommended.
Given the recent improvements in solar panel technology, solar and wind power are neck to neck on ROI and efficiency. However, the decision to go wind or solar depends on the location feasibility and fit to purpose. From our experience in installing multiple solar, wind and hybrid system, we offer the following thumb rule using the process of elimination: Use wind power at open spaces with continuous wind only. Remember, a wind mill on a high place does not guarantee high wind. Wind mill design requires wind measurements. In crowded residential areas (typical of Indian cities), do not install wind mill at heights higher than 16 metres to avoid maintenance issues which is important for wind turbines. Wind power suits best for off-grid system, however the most optimal is a hybrid (solar and wind) system.
Technically, a grid connected system can work as a back-up. But due to safety guidelines, a grid connected system is mandated to go into shutdown mode. Hence such a system should not be considered as a backup system. If the requirement is a backup system, we do have custom solutions for the same. While on this topic you do not have to continue using your exisitng battery based UPS system in tandem with the grid tied solar power system.