Adding battery storage to an existing Feed-in Tariff (FIT) site
As mentioned in other posts a battery usually has a dramatic effect on the consumption of energy generated from a solar system. A typical household will consume about 20% of the solar power generated by a system. That is because the solar obviously generates power during the daylight hours and peak generation is usually around midday (obviously depending on weather). Peak demand on the other hand is usually early to late evening and early in the morning. So the best way to boost self consumption is to use a battery which then charges using the excess solar during the day and releases that stored energy in the evening and overnight.
With a FIT scheme you are paid for the energy you produce regardless of how much you use yourself. With a typical solar installation you will only consume about 20% of the energy produced. This means the rest of the time you are importing energy from the grid at full price. However adding a battery will usually increase self consumption to about 80%. This means you are importing a lot less expensive energy from the grid. For a new solar system this makes the addition of a battery a no brainer.
However for a FIT installation its even better. You effectively get to use more of the energy that you are being paid for. The return on investment for this kind of installation is even quicker than the normal solar installation. Also even if you are coming to the end of the FIT scheme (20 years usually) you can still keep the battery for future use.
If installed correctly you can also use the battery for time-shifting energy and charge using grid power at off-peak times (usually at night) and then utilise during the day. This is especially important during the winter months when generation during the day is often low.