Grid Vs Off Grid Solar Systems

complete grid connect solar system

There are two different styles of solar systems around, the off grid solar system and the grid connect solar system. An off grid solar system requires batteries to store the power which the solar panels create and your house draws the power from the batteries. Because bad weather often occurs and can last for extended periods of time, the solar panels are not guaranteed to receive enough sunlight to charge the batteries every day. For this reason off grid solar systems are commonly used in conjunction with a wind power source or back up generator. Having batteries as part of the system makes off grid solar systems more expensive to set up than grid connected solar systems. This is why the majority of off grid systems are in remote areas where it would be very expensive to run mains power to.

Grid connect solar systems work in conjunction with mains power and do not need any batteries for storage. They work by the solar panels utilizing the sun’s natural energy and turning it into DC power. Mains power is what they call 240v AC power, so the DC power that the solar panels create needs to be converted into 240v AC power. This is where the grid connect inverter comes in. The inverter is the brains of the operation and its job is to convert the DC power into usable AC power as efficiently as possible. Once the power is fed from the solar panels through the inverter, it then travels into your power box where it is either used within your home or fed back into the grid. This is what eliminates the need for storage batteries. Instead of storing any excess power in batteries, it is fed back into the grid and you receive a credit from the electricity retailer.How grid connected solar systems work

In Australia there are 2 different kinds of feed in tariffs which are used depending on which state you live in. There is a gross feed in tariff and a net feed in tariff. When you go onto a feed in tariff your electricity meter needs to either be replaced or reprogrammed. This is so the meter can comprehend which direction the power travelling through it is going. A gross feed in tariff is where all the power generated is fed back into the grid and a credit is given which is then subtracted from the amount of electricity which you have purchased from the grid. A net feed in tariff is where the power produced by the solar system is supplied to your home first. So once it leaves the inverter, if there is anything drawing power in your home, it will bypass the meter and go directly into your home. The surplus that is not needed in your home is then fed back into the grid for a credit from your electricity retailer.

The amount of money that retailers are paying for the power fed back into the grid has fluctuated dramatically over the last ten years. Currently the rate most electricity retailers are offering is less than half of what consumers are purchasing it for. Because of this I believe the use of storage batteries is going to become more and more popular, unless consumers start getting paid something close to what they are paying for power.

If you need further information about what type of solar system best suits your energy needs then give us a call on 0427 686 328. We can supply and arrange installation of high quality PV solar panels from Sunpower and REC with German SMA inverters.