Are Solar panels any good?

QuackQuackOops

Martyn1981 wrote: »

I don't think the returns have changed too much. [Apart from the high tariff, proportionately low cost period late 2011/early 2012, when returns became too high.]

Assuming a generation of approx 3,600 to 4,000kWh pa from a 4kWp system on your south facing roof, then you'd be looking at around £700 to £800 pa index linked for 20 years, against a cost of ........ well that's up to you to haggle, but lately most/many posters on the G&E board are slipping under £6k.

Also, whilst south facing is clearly best for maximum generation, off-south is fine, but expect lower gen, perhaps 20% if east or west (or a mix).

Additionally location has an effect, with an approx 20% difference between far south and far north UK.

Mart.

I didn't get any figures that matched anywhere near £800 a year.
I can only assume that those figures are based on a healthy doses of sunshine, down South.

The figures given were all nearer the £300 mark and it's just not enough of a return, especially when £6000 (just a little less) has to be forked out up front.

Martyn1981

QuackQuackOops wrote: »

I didn't get any figures that matched anywhere near £800 a year.
I can only assume that those figures are based on a healthy doses of sunshine, down South.

Nope, not down south.

I said 3,600 to 4,000kWh pa. Checking PVGIS for Edinburgh it gives me 894kWh/kWp for a south facing roof with a 35d pitch.

[there's a walkthrough in the PV FAQ section 5]

https://forums.moneysavingexpert.com/discussion/3872445

So 4kWp = 3,576kWh pa (as a pretty accurate guestimate)

FiT tariff 3,576 * 14.38p = £514
Export 1,788 (deemed 50%) * 4.77p = £85
Leccy savings (£80 to £160) = £120

Total £719 pa.

[Edit: Many salesman will suggest leccy savings equal to 50% consumption of generation. This is very, very hard. 25% to 30% is more reasonable. I have an E/W system spreading generation throughout the day, but only consume approx 33%. M.]

The PVGIS estimates are pretty accurate, but the default losses may be a bit high, explaining why most of us (boring) peeps on the 'talking about our generation' thread tend to do better.

My performance against targets for Cardiff are:

2011 101% (partial year)
2012 99%
2013 104%
2014 107% (if rest of year average)

My targets are unshaded, but my systems get a small amount of shading from a chimney.

Happy to run off a generation estimate for you if you give your rough location (nearest town/city), roof orientation and pitch. But you shouldn't really have any trouble working through PVGIS.

Apologies if any of this sounds like selling, I'm a PV'er, with no links to any installers. Just trying to share knowledge, which was the original purpose of creating the FAQ thread.

Mart.