davidwalker2 said:

I have a solar installation comprising 17 panels dating from 2010

As a side note.  Might be worth looking at the old panels and check the Peak Power.  As the panels are 14 years old they may only be producing 100 - 150W.  Newer panels Peak Power Output are in the 380 - 450W range.  The panels in themselves are not that expensive but the labour and the scaffolding is.

Have a look at Trina panels on a supplier web site like

https://midsummerwholesale.co.uk/buy/trina

The increased energy production could be offset against the price paid to buy in energy to the property.  Maybe battery storage could be factored in?  As always if you intend to make changes to your PV install check with your local MCS approved installer that all is well with the proposed design changes.  Eg will the inverter work with the newer panels and such.

The trouble with buying new ones is that you lose the FIT subsidy for the old ones.  My old panels are rated at 190W each, while new ones can be anything up to 450W.  But the FIT payments are tied to a particular set of panels.  Take them off your roof, and the payments stop.

as the original poster  presumably will have 10 or 15 years of payments left to come based on the 2010 start year, the incentive to not break that original contract is quite high  ;-)
At least for now,  2010 installation is worth a lot more than a modern one of the same roof area, even if that the new one would generate 3 times as much . In ten years time, that may not be the case.

It does make one wonder though, if a panel fails, does it have to be replaced with an old style one..
Mike

as the original poster  presumably will have 10 or 15 years of payments left to come based on the 2010 start year, the incentive to not break that original contract is quite high  ;-)
At least for now,  2010 installation is worth a lot more than a modern one of the same roof area, even if that the new one would generate 3 times as much . In ten years time, that may not be the case.

It does make one wonder though, if a panel fails, does it have to be replaced with an old style one..
Mike

It's actually more than your graph suggests - I think that's the initial unit price when joining the scheme in those years - it's then index linked, so 'class of 2010' are currently paid something like 68.3p/kWh generated.

   - Andy.