Is it worth paying an extra £1200.00 for 1 more panel?

GOJO · Sep 10, 2013

Hi,
I have two quotes one for 11 panels (in a 8 / 3 configuration - a samil inverter on the 8 panels and a soladin inverter for the 3 panels) and then a quote for 12 panels ( 8 / 4 configuration with a samil inverter again on the 8 and 4 micro inverters on the 4) difference in the 2 quotes is £1200.00 is it worth the extra for 1 more panel and the micro inverters? Or is this a really stupid question?
Cheers, Jo

Worcester · Sep 10, 2013

See your other post, depending upon the panels spec, you should be able to get 8+4 the Power one PVI 3.0 OUTD for the same price as the 8+3 and the two inverters if you haggle

shanky887614 · Sep 10, 2013

Get one inverter if you can

Mastervolt or sunnyboy are two i can think of that can have 2 or more seperate strings on the one inverter (inverter costs under 1000 last time i bothered looking last year)

(Ive helped installs using these on 4kw systems)

FB. · Sep 10, 2013

I doubt that £1200 extra cost for just one extra panel will turn out to be worthwhile.

I have 15 panels and they generated 3300kWh last year, which is 220kWh per panel.

At current FiT rates (around 16.5-17p per kWh) one panel would "earn" £37.40 per year. It'd take 32 years in today's money to pay it off. Even allowing for inflation indexing of the FiT rate at 3-4% per year you'd still be looking at only £74 of earnings in the final FiT year and a payback period close to 25 years.
In-house usage of one-third of the power generated, at 14p per kWh cost of electricity, adds another £10 of savings per year.

All-in-all, an extra panel at £1200 would probably only reach payback around year 20-22, so would fail to earn its keep.

So in summary: I would not spend £1200 for an extra panel. I might spend up to half that which would give a payback period a little over ten years.