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zigs

Solar p.v. systems question

We are intending to install a 5 Kw pv system at a cost of 29,000.

We hopefully be using net metering. Is there anyone on here that is already using this size system?

Would be nice to know how its running & what average bills/income are like.

A thing that just occured to me, reading a thread by someone off the grid, was what happens if the grid fails? will all the electricity be sucked out of our house crybaby confused2
RichardW

Re: Solar p.v. systems question

ziggy searchfield wrote:
We are intending to install a 5 Kw pv system at a cost of 29,000.

We hopefully be using net metering. Is there anyone on here that is already using this size system?

Would be nice to know how its running & what average bills/income are like.

A thing that just occured to me, reading a thread by someone off the grid, was what happens if the grid fails? will all the electricity be sucked out of our house crybaby confused2


Are you using a direct to grid converter or using a battery bank? If the former in a power cut you have NO power too. Unless you get one of the newest systems that can now auto disconect the grid & carry on providing power to your house. In the latter you need a disconect to stop the power you are making killing the workers on the line (& trying to power the neighbours).

Justme
dougal

Ordinarily a grid-tie system does NOT give you a supply independent of the grid!

IMHO (and everyone has an opinion - I hope mine is accepted as having some justification) the *economics* of solar pv are heavily dependent on the contract you make with the electricity supply company. (And yes, what grants you can get.)
This is *specially* true for solar pv because most of the power is generated at *exactly* the time when you yourself are likely to be using the least power. Summer daytime.

Paul seems to have given up on posting here, but is still maintaining his website
http://www.alternative-energy.co.uk/SOLAR_PV_INSTALL.html
RichardW

dougal wrote:
Ordinarily a grid-tie system does NOT give you a supply independent of the grid!


The newest ones do now. It was / is the only down side of a grid tie set up if you already have grid power.

justme
dougal

I'm not disagreeing that it is possible (with many systems).
I'm just saying it's usually an extra cost option, when it is available! Very Happy
zigs

cheers guys, that bit about electrocuting linesmen is a good point, if the grid is off, how do they check if power is being generated from a different source before working ?

One of the people who came to view the house at the weekend was a solar engineer, local to me, heres their website.

http://www.ecofirst.net/shop/Results1.asp?Category=26

like the price for the tube systems, think i've budgeted for twice that much on our conversion.

incidentally, sold this house in 3 days of it being on the market.
dougal

Re: Solar p.v. systems question

ziggy searchfield wrote:
We are intending to install a 5 Kw pv system at a cost of 29,000.


Did you note that Paul's system cost about 17k (gross before deducting any grants but he combined it with other roof work to minimise scaffolding costs) ?

He has seen a peak output of about 4.25kw.
But during December and January, his AVERAGE DAILY TOTAL output was just 2kwh.
zigs

Re: Solar p.v. systems question

dougal wrote:
ziggy searchfield wrote:
We are intending to install a 5 Kw pv system at a cost of 29,000.


Did you note that Paul's system cost about 17k (gross before deducting any grants but he combined it with other roof work to minimise scaffolding costs) ?

He has seen a peak output of about 4.25kw.
But during December and January, his AVERAGE DAILY TOTAL output was just 2kwh.


i did Dougal, we wanted to go for the bigger system to get some dosh back on a regular basis, have spoken to the estate agent & he says if we want to sell up, he'll add the cost of the system onto the selling price. especially if you can show paperwork backing up the income claims.

after the grant, it'll cost 14000
dougal

Ziggy, its that compared to Paul's yours looks like being 17% bigger but 70% more expensive...

Paul's 2kwh/day (in midwinter) means the production of electricity worth... maybe 30p a day (as substitution, less for export).
He looks as though he is going to produce about 3250 kwh TOTAL or thereabouts of electricity (whether used internally or exported) over the 12 months.
How much is that worth as income?
RichardW

dougal wrote:
He looks as though he is going to produce about 3250 kwh TOTAL or thereabouts of electricity (whether used internally or exported) over the 12 months.
How much is that worth as income?


Dont know about income but would only save me 325 per year at purchased prices hardly worth it.

Justme
zigs

i see, so solar pv is just not worth the effort then ?
RichardW

ziggy searchfield wrote:
i see, so solar pv is just not worth the effort then ?


I guess that depends on if

a, you have other power avaliable
b, you have spare money (dont borrow it or the interest will cost more than it makes)
c, you care about how your power is made


Justme
zigs

sorry, i didn't mean it to sound like that, I do care how its produced of course, i meant it doesn't sound worth it in its present form.

i will put it on hold for now, till i've developed my new system, i built a prototype but couldn't switch it on because it could have blown up, will add an expansion chamber when i put it back together.
alternative-energy

Hi Paul here... ears were burning...

Dougal is right about the projected kwh for the year.

3200 kwh at 5p generated. 665 kwh imported so far and with a previous bill of about 300 a year. Add onto this the 3 ROCs, which SSE are buying from me at 40 each and we should be 500 up on the year.
The payback should be between 12 - 16 years but price inflation or deflation will have an effect on the payback. Add to this the possible incentives of reduced council tax... if it ever comes about...we shall see!!!
Solar PV isnt installed as a shrewd financial investment.
My 8.6k could have been adding interest in a high interest account.
Adding interest charges from a loan onto the cost of the panels does make it look even less financially attractive.
However the prospect of being insulated from energy inflation and saving over 1.7 tonnes of CO2 each year does have advantages... we really enjoy having the solar PV and in the grand scheme of things (buying houses) it doesnt cost that much.

The 5kwp system does seem expensive compared to our system have you had any other quotes?
RichardW

Glad to see you considered the true costs (loss of interest or interest charged). Using your numbers your 500 up on the year is actualy only 70 after loss of interest in the first year, 48.50 year 2, 26 year 3, 2.23 year 4, So you will NEVER (well not in our life time) see a financial PAY BACK of your investment. What you will get is fixed price (fixed by the interest rate you are loosing) electricity.

Its interesting to look at what that amount (17k install costs quoted) of money could be worth in x years & how much per year the elec is realy costing


years value @ 5% elec cost per year
10 27,691.21 2769.12
11 29,075.77 2643.25
12 30,529.56 2544.13
13 32,056.04 2465.84
14 33,658.84 2404.20
15 35,341.78 2356.11
16 37,108.87 2319.30

Its easy to see that true finacial payback is not why these systems are installed. Add in the cost of any repairs / replacments & its easy to see why these systems are not taking off yet.


Justme
dougal

Welcome back Paul !

Justme's analysis is based on the 17k Gross install.
After grants it seems the out of pocket cost was 8k6.
So it ain't quite so bad.


IMHO the economics of solar pv look absolutely ghastly UNTIL the whopping government grant weighs in. (I'm not sure why they think the (foreign) manufacturers of the hardware deserve all this support.) But hey, there are grants, so look at the net price after the grant.

The economics look pretty poor still, at least until the ROCs are factored in.
These are government instigated support for those generating renewable energy for sale. Paul has done the neat trick of getting the government to pay him - for actually using up the electricity generated on his own roof.
I'm certain the scheme isn't supposed to work like that, but if it does in practice, take the money!

Even so, at current electricity prices (for that both bought and sold) you would expect such an installation (even after grants and generous ROC treatment) to leave you worse off than investing the money in a Building Society account. (That assumes zero residual value of the installation after something like 25 years - which as a working assumption seems reasonable.)

You do not install such a system to make money - even with the current generosity from government.

So I purposely didn't answer Ziggy's question "I see, so solar pv is just not worth the effort then ?" - because it comes down to *subjective* personal value of "worth" not financial justifications.

Because so much of the power is generated during *summer daytime*, unless you reorganise your life around it, a lot of the power is going to be exported. The financial worth of that is much less than using it instead of buying in electricity. And what its worth in practice depends on the deal you can find.
But what do most folk use electricity for during summer daytime? Running the air conditioning? Surely not!
alternative-energy

dougal said
Quote:
You do not install such a system to make money - even with the current generosity from government.


absolutely true. There are far better investments... have you seen the rise in the price of uranium at the moment!! Its all about how you would like the energy in your home to be generated and experimenting with a potentially different energy structure ( low voltage, low carbon, safe and local)

dougal said
Quote:

But what do most folk use electricity for during summer daytime? Running the air conditioning? Surely not!


You've hit the nail on the head again dougal... Funny, after 2 months after my PV install my neighbour fitting a professional looking 3kw wall mounted air con. I'm making the stuff and next door he's using it like there's no tomorrow!!! Talk about different priorities!!!

My favourite way of using the electricity in the summer is to cut all my wood for the wood burner. I can easily generate over 3kw when the sun is out and the circular saw uses less energy than this. All the wood cut from the energy on my roof - nice.
I can also make plenty of boiling water using a 1.6kw element but i realise that making boiling water through electricity is not an efficient use.
zigs

I had been building this system to generate electric from sunshine without the use of p.v.

was going to keep my mouth shut till i knew it worked, but, whilst surfing for parts for it, I have found the Germans have already built it. Basically, water from the solar panel goes through a pre heat to create steam, drives a turbine to produce electric, gets cooled in a heat exchanger & goes back up to the solar panel.

so here it is; http://www.solar-international.eu/

as soon as i get the dosh through for the conversion, i'm going to build a full scale one, with the waste heat going into an underground insulated heat store, for winter use.

Good thing i asked you guys about p.v. i might have spent a lot of dosh on something i can build myself Smile
dougal

Re: Solar p.v. systems question

ziggy searchfield wrote:
We are intending to install a 5 Kw pv system at a cost of 29,000.

We hopefully be using net metering. Is there anyone on here that is already using this size system?
...


You have come rather a long way from that original post.

However, I fear the direction you have chosen is unlikely to bring fulfilment.
I wish you luck.
RichardW

Looking at the german site they are not heating the water to steam using solar. They are PRE heating the water then using OIL to boil it. Ok they quote using good veg oil but......

Justme
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