Types of inverters

There are three main types of solar PV and storage systems: grid-tied, hybrid and off-grid. They all have their advantages and disadvantages, and it really comes down to the customer’s current energy supply and what they want to get out of the system.

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Grid-tied – This system is connected to the UK power grid and is the most common type of solar PV system. It uses a standard inverter to produce a constant AC output to your home. The electricity that is generated (if not used) can be exported and sold back to the grid.

One disadvantage of this type of system is that when the power goes out, so does your system. This is for safety reasons. Grid-tied inverters must automatically disconnect when they don’t sense the grid. This means that you cannot provide power during a power cut and you can’t store energy for later use. The solution is installing an AC-coupled system where the original grid tied inverter is coupled with a battery back-up inverter. This is a great solution for customers who want to install solar now to take advantage of incentives but aren’t ready to invest in the batteries just yet, or, use the majority of the generated electricity during the day. The installation of batteries at a later date will require the cost for an additional inverter.

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Hybrid – This system is a grid tied system with battery back-up meaning you have power during an outage from the grid. With this type of system, you get the best of both worlds because you’re still connected to the grid and can qualify for SEG, while also lowering your utility bill. You can also use energy during peak demand times by storing the energy in your battery bank for later use.

Essential loads that are needed when the grid power is down are isolated into a back-up sub panel so you don't use up all the stored energy.

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Off-grid - Off-grid systems are great for customers who can’t easily connect to the grid. This may be because of geographical location or high cost of bringing in the power supply.

The benefits of an off-grid system is that a person can become energy self-sufficient and can power remote places away from the grid. You also have fixed energy costs and won’t be getting a bill from your energy use.