Hybrid solar systems generate power in the same way as a common grid-tie solar system but use special hybrid inverters and batteries to store energy for later use. This ability to store energy enables most hybrid systems to also operate as a backup power supply during a blackout, similar to a UPS system.
A battery can be added to any existing grid-tie solar system at any time using an ‘AC battery system’. AC batteries like Tesla Powerwall 2 are quite popular and more options are becoming available. As inverter technology and batteries are evolving rapidly it is not always worth spending extra money on a ‘battery ready system’ unless you plan on adding a battery within 2 years. Since battery technology is advancing quickly if you wait too long to add batteries the system may become obsolete.
Many governments and network operators have reduced the solar feed-in tariff or FiT (money or credit received for feeding solar energy to the grid). This means traditional grid-feed solar systems have become less attractive as most people are working during the day and not home to use the solar energy as it is generated, thus the energy is fed into the grid for very little return.
A solar hybrid system stores your excess solar energy and can also provide back-up power during a blackout. This is perfect for homeowners although, for the majority of businesses that operate during the daylight hours, a common grid-feed solar system is still the most economical choice.
The ability to store and use your solar energy when desired is referred to as self-use or self-consumption. It works in the same way as an off-grid power system but the battery capacity required is far less, usually just enough to cover peak consumption (8 hours or less) as opposed to 3-5 days with a typical off-grid system.
How Does It Work?
A hybrid solar power system is a combination of a Grid-connected system and an off-grid system. The working of the system is explained below ;
- During Sunshine hours, the loads are run by the solar energy generated.
- In case the solar energy generated is more than what is required by the loads, the excess energy charges the batteries. If there is still excess energy, the same can be exported to the power utility grid. However, the grid is mandatory for the export of energy. But for running the loads and for charging the batteries, the grid is not required.
- In case the solar energy generated is not sufficient to run the loads, the differential energy can be either drawn from the grid or the batteries (This is programmable). That is if the grid is available, it can be drawn from the grid or it can be drawn from the battery if the grid is not available. Or it can be programmed to take 10% from the battery and the remaining from the grid. Or in other words, This is a very versatile system and highly configurable.
- In the non-sunshine hours as well, it can be programmed to draw the energy either from the grid or the battery.
- Say during the non-sun-shine hours, if the grid is not available, the entire energy is drawn from the Batteries.
- As explained earlier, Excess energy can be traded with a power utility company (Grid). At the end of the billing cycle, if You have given more energy to the grid, the utility company pays you at the prevailing tariff. If you have brought energy from the grid, the power utility company bills you at the prevailing tariff.