Solar panels for dummies :)

elantan

Have put the info into the link that is on the FAQ page using 90 and -90 degrees, with an angle of both 56 and 58 it appears that the SAP estimate is over generous the other readings I got where 2,260 per year for a 4kw system, if this I the case then I have worked it out as just less than £350 a year along with a further £100 approx for the electricity generation, this seems to make paying £6k for a system unviable for us

Can someone check if I have my facts and figures right ?

Thanks

Martyn1981

Evening El.

Quick check, I think you've done it correctly. PVGIS is a great tool once you get to grips with it.

My less precise 'pin in the area' gave me 1,160 for 56deg and 1,140 for 58deg, so approx 2,300kWh pa.

So, FIT 2,300*15.44p = £355 plus
export (you may have missed this bit) 2,300/2 * 4.64p = £53 plus
leccy savings guess of £100

Total £500pa

on a £6k cost that's a gross return (ignoring cost of capital) of 8.3%. Not great, not awful, hard to call.

If you value your capital @ 3%, then net return is 5%, so 20 years covers your lost interest and pays you your money back. So breakeven.

Then there is index linking v's replacement inverter and any additional maintenance.

Personally, I think the returns need to go up a bit, or the cost down a bit.

Where did the E / W bit come from? You've mentioned a south wall, a SE wall, and a SW roof. Are the 56+58deg's both roofs or walls?

Changing the entries to -45 & +45, improves the total to 2,890. [edit: rough income total of £600 to £650]

Hate to say this, but the package (just too far north, just too far off south, just too far from £5k) isn't really looking great at the moment.

Don't give up yet - any chance of ground mounting them, due south? (you will need planning permission.)

Mart.

elantan

Hi Marty ( you do suit that name ... It's a friendly name I reckon )

Many thanks for replying again, this is where I get all embarrassed, I thought my roofs were south west and south east but the guy checked them today and said they technically come under east and west ( maybe don't ever ask me to help if your lost lol) he said they are close to south east and south west but where he would have to place the panels it's deff east and west, I was told the south wall is not high enough to clear tree height etc so to forget that one as well. I did discuss ground mounted panels, but due to shading they ain't gonna work either ( buildings , trees and hedges etc)

With all that in mind I think for us just now sadly solar panels will not be a financially viable option for us, this is really frustrating as we really fancied having them and have talked about them in and off for years, but at estimated returns of £500 ( yes I did forget the export yikes) and with the need to replace inverters and maintain the panels it just isn't worth it for us sadly

If the cost is £6k and over a ten year period we will get £10k then add into that an inverter ( or two) replacement say £1k each and two inverters (7 years each) were up at £8k spend without looking at maintenance etc ..I know it's index linked but the increase is gonna be about £12.50 a year so just not financially viable at this time... That's the way we looked at it

We did discuss wind turbines with the guy, he suggests that we would be best to leave it for 5 or so years till planning permission etc eases then to go for that as we are in and ideal place to get it

elantan

Incidentally the 56 and 58 were both on the roofs the 56 west side and 58 east side ( I have a weird shaped house )

Martyn1981

elantan wrote: »

With all that in mind I think for us just now sadly solar panels will not be a financially viable option for us, this is really frustrating as we really fancied having them and have talked about them in and off for years, but at estimated returns of £500 ( yes I did forget the export yikes) and with the need to replace inverters and maintain the panels it just isn't worth it for us sadly

We did discuss wind turbines with the guy, he suggests that we would be best to leave it for 5 or so years till planning permission etc eases then to go for that as we are in and ideal place to get it

Hiya El.

Sometimes it just doesn't work out. Hope I'm not rubbing salt into the wounds, but against that 2,300kWh figure for E/W and 56/58deg, I got these comparisons:

Changing orientation to SE/SW - 2890
changing pitch to 35deg - 2600
moving you to Birmingham(!) - 2600
plus of course the messy pricing at the moment due to anti-dumping fun and games.

So looks like a string of small negatives just gang up on you.

I really like the idea of wind, but can't have it here, I checked on a few estimator sites like the EST, almost half the recommend minimum so had to abandon such hopes, and went for the non-optimal PV extension instead.

If you're interested in wind, scour / join some of the renewables sites for help and advice. It's more complex (and part art, part love affair), but from what I've read, it's also more fun.

All the best.

Marty.

elantan

Yeah it looks like for us it just ain't a goer ... But we know that now and it was good to find out, have to admit I have enjoyed learning about it all ... Maybe we just need to move further south

Don't worry about running salt in the wound ... If someone else can get it and save money or make money then I am delighted for others

Will look forward to learning about turbines now ... Who knows maybe that will work out better for us as we deff live in a very windy area

jackyann

I am rather confused by your elevations etc. (not you, just me not having enough time to sit and work them out!) but wondered if you could consider solar thermal panels instead? May be a no-go, because of linking them to your current hot water system, but we are delighted with ours.

elantan

I think solar thermal could be good but tbh it will only heat the water so not really what we are looking for, I imagine ( although I maybe wrong) that the same would apply ... Ie due to te positioning of panels we wouldn't be generating enough electricity to make it a viable option, the problem seems to be more with the position of the panels and the position where we live more than anything ... If we are generating 2,300 units per year then it isn't worth out while in investing

As I say I could be wrong but I'm under the impression pv panels and thermal panels whilst do two different jobs se to work on the same principals therefore rendering it a mute subject ( of course if I'm wrong please feel free to correct me )

WestonDave

Not sure how cost effective they are, but whilst at the self build place in Swindon recently, I saw some thermal panels which work via a heat pump type system. With these its more about extracting the surface heat from the panels, so even on an overcast day, (and potentially on a cold day) its possible to extract heat from the panel which can then be used via an exchanger to heat hot water. I think the system they had was a Worcester Bosch one but could be wrong. They had it rigged up via a couple of panels and the "boiler" to a bank of 4 radiators which were all hot - although obviously it was extracting heat from a warm indoor room rather than outdoors. It clearly worked though judging by the heat in the radiators and the ice forming on the panels. The big question is how well do they work and how cost effective are they - although being sold by a big name like Worcester does at least give them some credibility!

solarpvman

elantan wrote: »

A couple of q's if you don't mind, once the FIT deal finishes ( 20 years or so?) apart from the £100 ( roughly) saving per year what are the financial advantages of having a system? For example, is there a way in which we can store the energy gathered from the sun so that it will slowly feed back into consumption at night time etc?

I've not read all the replies sy if I duplicate.
storing the energy: effectively no you can't easily do that. you would have to store it in a battery or store it as hot water that your immersion heats up. both require extra kit.

if you go for the immersion approach you MUST change your element to a 1Kw one and not your existing 3Kw one...(I can explain if you want!!)

is the deal really worthwhile anymore now the tariffs have changed? I got mine a couple of years back and it was a no brainer. with the new deal the payback is V long and really you are doing all this to assuage your green credentials (nto a bad thing of course but you aint gonna make that much money out of it)

PS all the tinkering of roof elevations etc etc don't make THAT much difference. Shading WILL make a difference. As an example our roof points in the wrong direction (wrong in the sense it is outside the recommended N-S-E-W facing direction) we still generate LOADS. Neighbours have just extended their loft which is not good but only affects the early morning generation and no trees get in the way.

regarding the thermal panels. I wish we had got one installed at the same time as the PV. more difficult to install but as we are at home a lot with kids every last drop of that hot water would be used...no roof space now :-(