Solar: how much you paid (£) how much you have generated (kWh) and date of install.

cepheus

I suggest we just list the following to keep it simple:

a) the cost of the system to install assuming you fully own it (£)
b) the total electricity produced to date (kWh) (used internally + exported)
c) date of installation (month and year)

This should be enough to calculate all we need to know depending on an agreed p/kWh which we shall leave out for now.

You may also wish to include, your approximate location, orientation of roof & area of panels but these are supplementary.

The_Green_Hornet

Who is this "we" you keep on about?

tunnel

What is the point of this thread?
Are you trying to collate some more info to continue your argument with Mart?

Martyn1981

tunnel wrote: »

What is the point of this thread?
Are you trying to collate some more info to continue your argument with Mart?

I'm also not sure of the point, and suspect it's simply to show that PV was more expensive than wind. But will have a play.

@Cepheus

My 2011 ESE install was just over £11k for 3.58kWp.
My 2012 WNW install was just over £4k for 2kWp.

If you have a quick look at recent threads on this forum, you'll see quite a few at, or under £5k for ~4kWp, so my calculations based on £5k seem fair, being aimed at the better, but not extreme end. If you wish to check my generation estimates of 4MWh, then do so with PVGIS, you'll see that, that is a fair figure for 4kWp south facing in the UK.

But, going back to your position:

cepheus wrote: »

If you remember, my view is that solar is unlikely to become cost effective, for this country as a whole and we should be concentrating on more cost effective renewables such as wind and conservation. This situation remains the case in high latitudes such as the UK.

the simplest way to review cost of generation, and see if your statement is true, is to compare the subsidy or strike prices for a unit of leccy, since these reflect the actual costs/incomes of what is being rolled out.

FiTs:
0 to 4kWp of PV = 12.92p/kWh (from 1/7/15 probable further drop on 1/10/15).
Upto 100kWp of PV = 9.63p/kWh
0 to 100kW of wind = 14.45p/kWh (from 1/4/15 to 31/3/16)

CfD auction:
Off-shore wind - £119.89/MWh (2017/18)
On-shore wind - £79.99/MWh (2017/18)
PV - £79.23/MWh (2016/17)
[Note: I've ignored the 2015/16 PV price of £50/MWh as I said at the time, that I didn't think this would happen, it was just a punt under the CfD system, and the schemes have since been withdrawn.]

Of course this is only the start of the argument, since support of PV by wealthier nations, now means that PV in poorer, but sun rich nations (where they may generate twice as much, improving the economics by a factor of 2) is starting to undercut coal generation costs, even without factoring in CO2 and pollution.

Also, your support of wind without PV, leaves you dangerously open to the argument of what we do, when the wind isn't blowing. (The same applies to supporting PV without wind). Since PV and wind in the UK are near perfect partners, they each help to full in for when the other is weakest. Without a full mix of renewables, the whole house of cards will fall down, before it has a chance to establish and strengthen.

Yet another factor looking forward is large scale storage. To get the most value out of that storage means making the most use of it. Storing excess PV generation during the BST months (in conjunction with excess wind storage in the GMT months (plus any other excesses eg tidal)) will help to justify its costs, and improve the economics.

A long time ago on a G&E thread I said that PV was important, but that it could never match wind in the UK on price. I don't think I've ever been more pleased to be wrong.

Mart.

EricMears

What use could we make of such data ?

jimjames

EricMears wrote: »

What use could we make of such data ?

Not a lot. Especially when it doesn't include system size in the details requested so I'll include it on mine.

All my data is publicly visible on my blog

a) £8995
b) 11000 kWh
c) Nov 2011
d) 3kWp

Currently it would probably cost half of that.

So far that's 81p per kWh. For 3.5 years worth of generation.

Extrapolate up to 25 years and it comes out at 11p per kWh so for a current installation that would be 5.5p per kWh.

Is that viable?

Martyn1981

EricMears wrote: »

What use could we make of such data ?

Thinking about it Eric, it's probably for cepheus to check my numbers with 'real' figures. That actually seems like a reasonable thing to do. However, as I tried to stress in my earlier post, they aren't my numbers - the prices are real, and are taken from threads this last 6 to 8 months, and the generation figures are from PVGIS, which seem to be extremely reliable, though perhaps slightly low as default system losses may now be a tad high.

@jimjames - thought I'd run with your suggestion and divide my cost by 40 years of generation, just for a laugh!

I added the cost of 2.5 inverters (@ £800 each) and divided by 161MWh, having taken average gen over the first 3 years, mutiplied by 40 years, then multiplied by 0.9 to represent panel degradation. I based degradation on 0.5% per year, giving me an average figure of 90%.

Cost per kWh came down to 10.9p.

Just for fun:-

Having further considered prices being posted this year, with quite a few below £5k (£4.5 to £5k), I'm even more confident that a new build with 3 to 4kWp of panels could be done for £1k/kWp just with scaffolding cost savings.

I appreciate that I'm starting to get a little silly now, and ignoring cost of capital, but that gives a unit cost of:

£4k plus £1k inverter replacement divided by 144MWh (4MWh * 40 years * 0.9(degradation)) = 3.47p/kWh.

Assuming the cost of install is covered by a repayment mortgage over 25 years, then including the inverter replacement, the total cost comes to approx £7,290 = 5.06p/kWh.

Mart.

EricMears

Martyn1981 wrote: »

Thinking about it Eric, it's probably for cepheus to check my numbers with 'real' figures. That actually seems like a reasonable thing to do.

I can say that my present installation is yielding even more than I forecast and the actual cost to me (net of FIT payments) is considerably less than zero pence per unit (as anticipated).

Since I have no intention of building another house, I'm not really interested in whether or not I'd need to install SP from the outset. If I change my mind, I'd check out (then) current costings but my gut feeling is that it would probably be a good idea.

cepheus

Martyn1981 wrote: »

I'm also not sure of the point, and suspect it's simply to show that PV was more expensive than wind. But will have a play.

This forum is about Green and ethical Moneysaving. Solar is less than 10% of that and the main interest is making money through subsidies. Wind has even less relevance for domestic use, since it's less economic on a small scale. Let's have some threads on the other environmental issues. Food waste is just one such example and anyone can do it.

cepheus

jimjames wrote: »

Not a lot. Especially when it doesn't include system size in the details requested so I'll include it on mine.

All my data is publicly visible on my blog

a) £8995
b) 11000 kWh
c) Nov 2011
d) 3kWp

Currently it would probably cost half of that.

So far that's 81p per kWh. For 3.5 years worth of generation.

Extrapolate up to 25 years and it comes out at 11p per kWh so for a current installation that would be 5.5p per kWh.

Is that viable?

OK, now were getting somewhere, that's 3070 Kwh per year. Presumably that £8995 includes all the costs? Of course these devices do deteriorate and require some maintenance & cleaning over that time. PS I did suggest system size in area (m2) & orientation. I'm not interested in manufacturers ratings.

cepheus

tunnel wrote: »

What is the point of this thread?
Are you trying to collate some more info to continue your argument with Mart?

Evidence. What would you trust, what the manufacturer claims a product does or how it has actually performed over a sufficiently long period? The date and installed price together with actual measurements of total kWh produced since installation should be sufficient to calculate all we need to know of their real value to society.

Perhaps what I missed out were the costs of cleaning and any other maintenance. I think the mean deterioration in output is about 0.5% a year, assuming they are cleaned regularly, but this should be visible in the kWh figures. How long do the inverters last BTW?