Based on their application, a Solar power plant is mainly of three types-

• Off-Grid/Decentralized Solar Power Plant

• On-Grid/Grid Tied/Grid Interactive/Grid Synchronized Solar Power Plant

• Hybrid Solar Power Plant

Q: What is an Off-Grid Solar Power Plant?

A: As we all have experienced this- Solar energy keeps changing all day long. As per scientific facts, the average times solar radiations changes in a day is 1,00,000 times. Why we need to consider this fact? Its simple, if Solar power is so variable, that means the power hence generated from Solar panels will vary 1,00,000 times a day. What to do now? The solution is – Use a storage device like a Battery in addition to Solar Panels. Solar panels need an additional power source like a battery to power the load in case of a variation in Solar energy generation. So, an off-grid Solar power plant is simply Solar panels combined with batteries. This helps a constant and uninterrupted power supply to the load attached. The inverter used here converts the DC power generated from Solar panels to DC power usable by batteries for charging purpose as well as converts the DC power available from Solar and Batteries into AC(Alternating current) power usable by the existing load like fans, refrigerator or LED bulbs at our homes.

Q: What is an On-Grid Solar Power plant?

A: Now, as we have understood what an Off-Grid Solar plant is and why batteries are required in an off-grid Solar plant, let us now understand what an On Grid Solar plant means. It is simply a Solar plant that works without Batteries. Now, we don’t need to get confused at all. If batteries are not there in support of Solar panels, how this plant will operate then? The answer is simple-Grid or the Government/DISCOM Electricity supply will support the Solar panels here. But the supply we get at most of the places is AC supply i.e. Alternating current supply! Here, the inverter is a bit smart. The grid Tied Inverter actually synchronizes itself with the Grid supply in order to convert the DC into AC. It senses a reference voltage from the grid for the conversion purpose. So, the Grid acts like a storage house for the Solar panels unlike batteries in an On-Grid/Grid Tied Solar plant. In case the Solar panel power reduces, the load gets shifted to Grid automatically as load is connected in parallel to the Solar Inverter and the Grid.

Q: What is a Hybrid Solar Power Plant?

A: The combination of On-Grid and Off-Grid Solar Power plants is called a Hybrid Solar Power Plant. Here, the Hybrid Solar Inverter is another intelligent device that senses the grid all time along with the Solar Power available and the power left/stored in the batteries. In a Hybrid Solar plant, when Grid electricity goes OFF, the Inverter seeks help from the batteries in order to power the load along with Solar and stops the power to be fed into the Grid to avoid any shock to the DISCOM staff. Also, when Grid comes ON, the Inverter turns the power in sharing mode from Solar panels and Grid and keeps the batteries at a threshold value in charged position. Though, in conditions as in India, a Hybrid Solar plant is not successful, as the Grid supply is not reliable. As the Hybrid Inverter uses sensing technology, so if there are frequent power cuts, its sensing time and shifting time will hamper the supply to load and hence the customer will feel like cheated for such a huge amount spent on the Solar plant’s installation. Its better to go for an Off-Grid Solar plant in most of the cases in India. Loyal Technologies