Currently it is worth it in relation to supporting the grid to smooth out national peak renewable energy generation to better meet peak demand, and, with some careful attention, is likely to pay itself back over time.
Before investing, it is worth considering whether you are likely to be charging an electric vehicle in the near future. If so, technology is evolving to allow “bi-directional charging” which means that you can store electricity in your vehicle battery in the same way as a stand-alone battery and then use it in your house. That does however depend on when your vehicle is at home and plugged in. If plugged in during the day, it could store electricity generated by your solar panels. If plugged in at night, it could store lower carbon and potentially lower cost night-time grid electricity.