Is it worth getting 2 extra solar panels?

thriftytracey

Currently we have 16 solar panels and a 5kwh battery. We are on Octopus Agile. We have space for two additional panels. We recommended the installer to friends in village and they are going ahead. I contacted the installer as he is in the village on Monday and he quoted £1000 for supply and install. We have been very pleased with the energy generation to date. I guess the extra would be exported back to the grid.

I am wondering if it is worth it. I believe one panel would generate 3 kilowatt a day (in summer).

Netexporter

The panels cost less than £200, so I imagine a large chunk of the price is scaffolding. As a general rule it is best to put up the maximum number of panels in the original installation, as the "fixed costs" are no higher. I think it would take the life of the panels (25 to 30 years) to get a return on your investment. 

thriftytracey

They dont use scaffolding. 

QrizB

thriftytracey said:

I am wondering if it is worth it. I believe one panel would generate 3 kilowatt a day (in summer).

Domestic panels are typically about 420 watts, which I guess could produce 3kWh on a perfect summer's day (about 7 O's).

A 420 watt panel might generate 400kWh per year. 400kWh, exported on Octopus Outgoing Fixed at 15p/kWh, would earn you about £60.

So you cold be looking at a return of £120 a year for an outlay of £1000.

But do check exactly what you've been quoted for, what your current annual generation-per-watt is, and your export tariff. if they're 300 watt panels and you're on a tariff that only pays 5pkWh, thet £120 could really be £30.

Screwdriva

thriftytracey said:

Currently we have 16 solar panels and a 5kwh battery. We are on Octopus Agile. We have space for two additional panels. We recommended the installer to friends in village and they are going ahead. I contacted the installer as he is in the village on Monday and he quoted £1000 for supply and install.

Hi Tracey,

I’m pretty sure the installer will negotiate on that price I think £800 is a realistic target & worth an offer. 

What many don’t factor in is the cost of the hardware and optimizer, so a cost of around £3-400 per panel is fair in my view and has been my experience with system expansions. 

I’d recommend switching from Agile to Flux for greater export earnings from your expanded system. 

thriftytracey

Screwdriva said:

thriftytracey said:

Currently we have 16 solar panels and a 5kwh battery. We are on Octopus Agile. We have space for two additional panels. We recommended the installer to friends in village and they are going ahead. I contacted the installer as he is in the village on Monday and he quoted £1000 for supply and install.

Hi Tracey,

I’m pretty sure the installer will negotiate on that price I think £800 is a realistic target & worth an offer. 

What many don’t factor in is the cost of the hardware and optimizer, so a cost of around £3-400 per panel is fair in my view and has been my experience with system expansions. 

I’d recommend switching from Agile to Flux for greater export earnings from your expanded system. 

They've come down £100.  

Exiled_Tyke

There's still a lot of unknowns here. 

1. what orientation are the new panels? 
2. as mentioned before are they 400w or less? 
3. what's you current export tariff? (If you are on FIT then you will need to leave deemed export to get the export benefit of these) 
4. Can these be wired into the existing inverter or will they need micro-inverters? (Or if a Solar Edge system, optimisers) 

I extended by two panels when I put the battery in but only because that way I could get the VAT back on the battery that way. 

QrizB

Exiled_Tyke said:

3. what's you current export tariff? (If you are on FIT then you will need to leave deemed export to get the export benefit of these)

OP's panels were installed last year (thread) so no FIT to worry about!

Martyn1981

Personal opinion here, but assuming these are 350Wp+ panels (just guessing on the original install being last year), then that's 0.7kWp+ for £900 (now), which isn't actually a bad price.

Cheaper of course to do it all at the same time, and when adding a bit more, will cost proprtionately less (rather than a bit more, like now), but still a decent price for an add-on.

Plus, it'll add a nice boost during the next few months, when gen is low, and you can use the extra. But as QrizB points out, most of the extra gen will be on top, so largely exported, when PV gen is high.

Screwdriva

We were able to get the cost of the 410W panels reduced a bit further. I think OP will be pleased with the extra generation. 

That said, the incremental cost for a panel during the first installation ranges from £250-300 (with optimizer). No system expansion cost can ever be that low, given the fixed costs involved, so it always makes sense to maximize South/ West roof aspect panel coverage during the initial quote. 

ispookie666

Leaving all this aside, what is your current export limit? Will the installer go back to DNO for further notification ?