solar panels

runner2021 · 6 October 2021 at 1:40PM

Hello, I'm new here. I've been quoted £11500 for a 3.6kwp system including Suntech Monocrystalline panels and a 5.8kw battery. The promised return seems too good to be true (payback in 7.5 years) so I'm thinking it must be. Any comments welcome

Merlin139 · 6 October 2021 at 1:47PM

How do they say you will get your return?

Would be good if you can show the calculations they gave you to give others a better idea. To back up the repayment they must have provided this.

Might be worth saying what they expect your system to produce each year and where in the country you are. Which way your system would face. Direction of roof. How many kWp on each roof and direction if more than one.

I had a 3.975 kWh system installed in 2014 and by this year with FIT and savings from paying for less electricity used I am now in profit.

Laycity · 6 October 2021 at 2:37PM

runner2021 said:

Hello, I'm new here. I've been quoted £11500 for a 3.6kwp system including Suntech Monocrystalline panels and a 5.8kw battery. The promised return seems too good to be true (payback in 7.5 years) so I'm thinking it must be. Any comments welcome

As mentioned, you need to see a better breakdown of how they come to the figure. What's the yearly PV generated prediction?

At first glance it looks expensive and I think you'll need to double the 7.5 years (at least).

arty688 · 6 October 2021 at 3:00PM

runner2021 said:

Hello, I'm new here. I've been quoted £11500 for a 3.6kwp system including Suntech Monocrystalline panels and a 5.8kw battery. The promised return seems too good to be true (payback in 7.5 years) so I'm thinking it must be. Any comments welcome

Yes too good to be true, best case assuming you use all that you generate , say 3.6kw system generates 3000KWh annually and electricity i say 20p kwh that's £600 per year. That would take a lot of inflation to payback in 7.5 year. So yes interested to see their calculations.

mickyduck55 · 6 October 2021 at 3:40PM

Looks VERY expensive to me... my son had a 6 kWh PV array and 7 kWh pylontech batteries installed last February 2020 for just over 7.6 K... clearly prices may have risen so I maybe out of date

Verdigris · 6 October 2021 at 4:17PM

Solar is about £1/Wp and the batteries could be bought for about £2500. So £8k tops if there aren't any special difficulties or additional control systems.

runner2021 · 6 October 2021 at 6:53PM

Hmm glad I asked, sounds like this might be a bit overpriced. Figures asked for above:

Installation cost: £11505 incl VAT

Predicted system output: 3660kWh/annum

Current assumed energy cost: 18.83p and predicted energy inflation @6%

Recent annual electric usage: 3490kWh per annum

Predicted on-site energy consumption: 100%

Roof pitch: 35 degrees

Degrees from south: 1 degree
Location: Southampton

10x Suntech Monocrystalline 360W panels (@£3500)

Solax 5.8kW triple power high voltage battery (@£3495)

Social Energy tariff

Guaranteed minimum solar energy output will be 3675kW for the first year

Combined annual average benefit of approximately £2051

Please say if there's anything else I need to include. Thanks in advance

ispookie666 · 6 October 2021 at 8:06PM

If you remove the cost of battery, the system comes to £2.2per watt, which I think is on the higher side (especially if they are all going on the same roof orientation with string inverter). Bigger the system, the lower the per watt cost (provider inverter does not need upsizing)
I had quotes from £1.54 to 2.54 per watt, the latter for LG panels and for micro inverters.

Petriix · 6 October 2021 at 8:12PM

Is that Project Solar?
If so, avoid like the plague!

QrizB · 6 October 2021 at 8:14PM

There's no way you'll use 100% of the electricity you generate. On a good summer's day you'll potentially generate 20kWh but your average daily consumption is only 9.6kWh and I'd imagine that (like most UK households) you use more in the winter than in the summer, so if you generate more than 10kWh you'll export the balance.

If you do really well you'll consume 2/3rds of what you generate, for an annual benefit of £461 in your first year. You might be able to export the other 1/3rd at 5p/kWh for an additional £61, a total of £522. Even allowing for 6% annual energy inflation I make it 15 years to pay back.

(I do note that the installer has quoted Social Energy's "Better Together" tariff, which potentially pays 20p/kWh for export. Unfortunately it's not easy to tell exactly what the deal is with Social Energy; their website is big on marketing but light on prices, which makes it impossible to compare.)