Adding extra Solar Panels to my existing set up

Zufre

As a householder with 8 Kyocera KD Series solar panels on my roof installed in 2011, I am thinking of maybe renewing them for more efficient newer panels and maybe adding some. I am on the original FIT rates. 
Question for Forumnites please:
Am I allowed to add to my existing set up and still benefit from the original FIT tariffs?
Is it worth looking at putting in newer panels for cost benefit?
Many thanks

QrizB

Would be better asked on the "Green and Ethical" subforum where most of the muesli-munching, sandal-wearing solar PV fans hang out.

I think that you'll be fine if you add a completely separate system, that operates independently of the FIT-eligible system.

If you modify your existing system you might be able to get your FIT payments pro-rata'ed, but if your supplier isn't happy you risk losing them entirely.

If you replace your existing panels you also risk losing your FIT.

Reed_Richards

My understanding is that any changes to your existing system render you ineligible for further FIT-scheme payments. If you have two independent systems then your smart meter is not going to be able to tell which is exporting electricity but if you switched to metered export rather than deemed export possibly you could get paid for your export.  Then there is the issue of DNO permission for how much electricity you aspire to export, no guarantee that you'll be allowed to export more than 3.68 kW (it depends on where you live).  

Netexporter

If the old system has made its ROI it might be better to start again. Panels are much more efficient now, so you could get far more than the 3.68kW limit of the past (subject to being granted a G99 connection).

Reed_Richards

Netexporter said:

If the old system has made its ROI it might be better to start again. Panels are much more efficient now, so you could get far more than the 3.68kW limit of the past (subject to being granted a G99 connection).

Except that it might be quite lucrative now, the FIT lasts for 20/25 years and the rates in 2011 were good.

jimjames

Netexporter said:

If the old system has made its ROI it might be better to start again. Panels are much more efficient now, so you could get far more than the 3.68kW limit of the past (subject to being granted a G99 connection).

If you're earning over £2000 plus RPI per year for the next 13 years then I wouldn't be changing anything that threw that money away. 
Bear in mind that if you do add extra panels to the existing setup and it gets pro-rated then that could disadvantage your existing FIT rates. Completely separate system alongside is probably a better option.