Solar Panels - why bother?

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Discussion

98elise

26,644 posts

162 months

Friday 30th June 2017
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kapiteinlangzaam said:
I'm doing quite well at the moment. 40KwH on good days, averaging around 30KwH on most days.





So that'll do half a Tesla! smile

Edited by kapiteinlangzaam on Sunday 14th May 16:11
An average driver will use about 7kWh per day, so that 30kWh will do 4 days of "fuel"

Armitage.Shanks

2,279 posts

86 months

Friday 30th June 2017
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^^^ That's a cool app. Is it easy to hook one up to a system? I think when mine was fitted there was mention of remote monitoring but I never explored it

MrJuice

3,372 posts

157 months

Friday 30th June 2017
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mikeiow said:
You nominally 'sell' 50% of what you generate to the power company you get your FIT payments from, for a fixed payment that is the same across them all.
I say "nominally" - they don't measure it but assume it. However, given they only pay pennies for that 'export' amount, it is peanuts.
We have a 4KW system (18 panels, I think), & we gave generated between 3,100 and 3,500kW each year for the past 6.5 years.
Clearly some here are generating more: I guess the East Midlands is a less sunny place!! Our roof is pretty ideally placed, south-facing not overlooked.
Let me get this straight, you install your power generator (wind, solar, whatever) and when you produce power, you get a FIT payment for every kWh produced. In addition, you get another payment from whoever you choose to sell your power to. The latter can be negligible.

What doesn't make sense is that you get this negligible payment from whoever you sell your power to but they then sell it on for market rates. These brokers are clearly making a lot of money.....?

Condi

17,211 posts

172 months

Friday 30th June 2017
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MrJuice said:
Let me get this straight, you install your power generator (wind, solar, whatever) and when you produce power, you get a FIT payment for every kWh produced. In addition, you get another payment from whoever you choose to sell your power to. The latter can be negligible.

What doesn't make sense is that you get this negligible payment from whoever you sell your power to but they then sell it on for market rates. These brokers are clearly making a lot of money.....?
Market rates are like... 14p/Kwh? The power company has to buy it considerably cheaper to make a profit, so they pay you, what, 5-7p/Kwh? The FIT payments are 4p/Kwh now, but previously were far more. The FIT tariff is, for most, more than the wholesale price of electric.

Paul Drawmer

4,878 posts

268 months

Saturday 1st July 2017
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MrJuice said:
Paul Drawmer said:
You will have to work out if it is worth it, but I can give you some figures. The size of your system will be expressed in kWp, the output is measured in kWh.
My system has been installed for 7 years. The size is 3.88kWp and from that I average 4000kWh per year. That's what I generate and what the FIT is based on, so you can extrapolate from your propose system size, and calculate an approximate income.
Some questions if I may

Who do you sell your power to? To the 'grid'? To your energy supplier? To some third party?

Is there much difference in the price different buyers pay?

How much do you get per kWh?
I sell my power back to my supplier (SSE), but I can still change suppliers and in that case will still sell to SSE as that is who the FIT supply contract is with.

My export is metered, so I get paid the export rate for the actual export, not the deemed 50%

The tariff rates are fixed and will be dependant on the type of installation and the start date of the contract, but they are index linked.
Since my FIT contract dates from a few years ago, the rates I get are not available now. (But my install costs were much higher too)
For current rates see here:
https://www.ofgem.gov.uk/publications-and-updates/...


Chrisgr31

13,485 posts

256 months

Saturday 1st July 2017
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dickymint said:
interested to know why not concered.
Because there is nothing I can do about it! It's very difficult to keep track of what you generate against what you use etc, unless you read your electric meter very day. There is no online tracking of the payment we get for the solar so its not east to see what the past history is, so might as well not bother.

mel

10,168 posts

276 months

Saturday 1st July 2017
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I'm struggling to make the sums add up, even using finest "man maths" it just makes no sense to me.

I've got what was described as almost the perfect roof on my new Garage I've been building and have even installed additional barer beams under the resin to take PV panels, I'm looking at an 18 panel set up,but would still be looking at10 years to be cash neutral with just the inverters and panels and nearer 18 years if i add in powerwalls!!!!

Since all my spare cash is currently going into the rest of the house renovation I'd considered financing the panels and hoped that the payments would be similar to the savings so kind of cash neutral until all paid off. But nope, not a chance, the sums are crazy so i'm shelving the idea until either ive finished the rest of the house and can revisit the idea with changed financials, or some sort of incentive is re introduced. It might just add up if you had £10K sitting in the bank earning FA but for me it's simply not going to happen, for now I'll stick with my nice big ribbed roof all prepped and ready but barren of panels.

Paul Drawmer

4,878 posts

268 months

Saturday 1st July 2017
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It looks as if the cost/payback is about the same ratio as when we bought into the idea.

When we installed our panels, it was just an investment decision as we approached retirement. We had the cash, and wanted to essentially buy an income. I predicted a cash recovery time of 9 years, and as the contract is for 25, I reckoned the income would be worth it as it is index linked (There will be a degradation factor but I haven't seen it yet).

On present performance, we will get capital recovery in less than one year now, so we are on track, and we will enjoy the income over the rest of the 25 year period.

We do not plan to move anymore!

If you have debt to service, and/or do not plan to stay put, then the maths is less obvious.

With regard to power storage...
We generate more than we use. During the summer this is quite extreme, and with a powerwall, regardless of how big it is, we would only be able to save a small amount by using the powerwall once the roof has stopped generating, and before it comes back on stream the next morning.

The small savings made by not buying from the grid during that time would take many many years (I think it was 40) to recover the cost of the powerwall.

The problem with the powerwall idea in a domestic installation is: When will you use all that stored electricity?

mr_spock

3,341 posts

216 months

Saturday 1st July 2017
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I'm in the process of buying a house with panels fitted already - and, handily, an EV charge point so I'm considering getting one to reduce my expected huge fuel costs.

The output back to the supplier, EDF in this case, is metered. From the bills they've sent me there are two payments. The "deemed" FIT at 4.91p per kWh and a metered FIT at 17.43p per kWh.

On a sample of bills from Sept to March it seems to bring in about £40 p/m in the winter and £60 p/m in the spring. So, about 110kWh per month in the darker months, and 300kWh p/m in the summer.

I think there are 8 panels on a string inverter. Pretty much south facing with no shade at all.

bazza white

3,562 posts

129 months

Saturday 1st July 2017
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I'm also looking at a house with panels owned outright. Estate agent says about £550/year is generated which is about double my electric bill now. If it is right it would virtually cover my gas and electricity costs.

When selling back to the grid is it all metered as I've read a 50% rule to. Do you get the same rate selling to the grid as you pay or is there 2 rates and is it done live or is a meter reading done at the end of the month and generation - usage = kw sold back.





Paul Drawmer

4,878 posts

268 months

Saturday 1st July 2017
quotequote all
bazza white said:
I'm also looking at a house with panels owned outright. Estate agent says about £550/year is generated which is about double my electric bill now. If it is right it would virtually cover my gas and electricity costs.

When selling back to the grid is it all metered as I've read a 50% rule to. Do you get the same rate selling to the grid as you pay or is there 2 rates and is it done live or is a meter reading done at the end of the month and generation - usage = kw sold back.
The FIT account is separate from the power you buy.

If there is an export meter, you will get the export paid according to that meter reading. If there is no export meter you will get paid at the export rate for 50% of the units you generate each month. There will be a dedicated generation meter.

The rates you get for generation and export are fixed each year and are based on the type and date of installation. It is not the same rate as you pay.

MrJuice

3,372 posts

157 months

Saturday 1st July 2017
quotequote all
mr_spock said:
I'm in the process of buying a house with panels fitted already - and, handily, an EV charge point so I'm considering getting one to reduce my expected huge fuel costs.

The output back to the supplier, EDF in this case, is metered. From the bills they've sent me there are two payments. The "deemed" FIT at 4.91p per kWh and a metered FIT at 17.43p per kWh.

On a sample of bills from Sept to March it seems to bring in about £40 p/m in the winter and £60 p/m in the spring. So, about 110kWh per month in the darker months, and 300kWh p/m in the summer.

I think there are 8 panels on a string inverter. Pretty much south facing with no shade at all.
Someone pays you 17p per kWh?

That sounds like a lot

mr_spock

3,341 posts

216 months

Saturday 1st July 2017
quotequote all
It's not me, the current owner installed the system 2/3 years ago and I guess they got the FIT from that time. I have copies of the EDF paperwork so I'm sure it's correct.

MrJuice

3,372 posts

157 months

Saturday 1st July 2017
quotequote all
Good work

It just sounds like a lot. I was under the impression the export price was in the low to mid pennies per kWh. Maybe yours is a historic and long term agreement

kambites

67,583 posts

222 months

Saturday 1st July 2017
quotequote all
MrJuice said:
Someone pays you 17p per kWh?
I think that's about what my parents are on, but they've had their pannels around ten years (they've already more than paid for themselves).

These days I'm not convinced domestic installations are economically viable.

Seany88

1,245 posts

221 months

Wednesday 7th February 2018
quotequote all
Paul Drawmer said:
It looks as if the cost/payback is about the same ratio as when we bought into the idea.

When we installed our panels, it was just an investment decision as we approached retirement. We had the cash, and wanted to essentially buy an income. I predicted a cash recovery time of 9 years, and as the contract is for 25, I reckoned the income would be worth it as it is index linked (There will be a degradation factor but I haven't seen it yet).

On present performance, we will get capital recovery in less than one year now, so we are on track, and we will enjoy the income over the rest of the 25 year period.

We do not plan to move anymore!

If you have debt to service, and/or do not plan to stay put, then the maths is less obvious.

With regard to power storage...
We generate more than we use. During the summer this is quite extreme, and with a powerwall, regardless of how big it is, we would only be able to save a small amount by using the powerwall once the roof has stopped generating, and before it comes back on stream the next morning.

The small savings made by not buying from the grid during that time would take many many years (I think it was 40) to recover the cost of the powerwall.

The problem with the powerwall idea in a domestic installation is: When will you use all that stored electricity?
Old thread I know but thinking about it, you just need a powerwall or battery bank that is sufficient to cover your maximum potential usage overnight, assuming there's enough sun every day to replenish the overnight usage to max again.

Chris Type R

8,038 posts

250 months

Thursday 8th February 2018
quotequote all
MrJuice said:
Someone pays you 17p per kWh?
That sounds like a lot
I think that the panels we acquired when we bought a house with an existing installation are 43.3 p/kWh generation tariff and 3.1 p/kWh export tariff - for 25 years. That's on a 2.02 kW capacity array which runs until 2036 (installed 2011).

I didn't (and wouldn't have) consciously paid more for the panels when buying the house, but it is a pleasant bonus.

The rate sounds high, but the owners paid a whopping £14,663 for the install and since we've lived here we've only generated 1315 units (3 winters, 2 summers) - £570 pa - which is barely break-even. They only derived benefit from the installation for 4 years. They're elderly and I expect were miss-sold. The installation itself is well sited in terms of being hidden, but poorly sited as the neighbour's tree casts shade over the installation for a large part of the day.



Edited by Chris Type R on Thursday 8th February 12:03