Solar panels Not worth the money

Petriix

gorgeousme said:

Thank you. So the consensus is positive then!  I will look into this a bit more now. 

The truth is "it's complicated"... 

It's very tempting to treat each kWh self-consumed as a saving at the peak import rate. However there are often times we we use the energy just because it's there rather than out of actual necessity.

For example today I diverted about 12kWh to my EV. I incidentally imported about 0.5kWh around that as clouds passed over and other domestic loads used the excess solar and the system was slow to respond. Roughly 96% efficient isn't too bad, but it cost me ~ 12p. If I'd charged overnight on Octopus Go it would have cost me 60p, so the saving is only 48p or ~ 4p per kWh.

I'm also aware of many people who divert as much excess as possible to heating water, even when it's not needed. Hard to put a value on that energy but certainly not whatever the peak electricity rate might have been.

A true reflection of actual savings would be to estimate the reduction in overall use - from prior to the installation or what it would have been without.

I've found that it's actually more expensive to try and use what I generate in comparison to just running things in the cheap window from 9:30pm. If more than 20% of the energy is coming from the grid in the peak period (say there's 2kW of surplus but the dishwasher uses 2.5kW) then it would have been cheaper to just run it from the grid overnight.

Ultimately it makes it much more difficult to calculate the true ROI. With my FIT payments and deemed exports I'm still likely to break even inside 8 years. If I was installing today I'm not sure it would make sense.

It's worth doing your own sums rather than looking at other people's anecdotal reports using imaginative methodology and their own unique circumstances. 

Magnitio

Interesting comment:

“It's worth doing your own sums rather than looking at other people's anecdotal reports using imaginative methodology“

It’s worth looking at what other people do; you don’t have to agree with them, but you may learn something useful.

Exiled_Tyke

Martyn1981 said:

If this helps for the future, assuming some normality is restored, and PV install prices fall, then for a 5kWp system, generating 5,000kWh pa, and costing £6k (I assume that the impacts of inflation will prevent prices going much cheaper), would at 2% (use of own cash/savings) work out at roughly 7p/kWh.

This inspired me to have a look at my own set up. But rather than repeat your exercise I've calculated (estimated!) the internal rate of return.  First my assumptions:  £7k initial cost.  FIT payments 12.5p at the start. own useage 45%. Generation 2,650kW pa. cost of electricity 15p and a total time period of 20 years.  If I include your assumption and estimate of a new inverter. Then the IRR is 2.43%. So not fantastic investment but certainly better that what the bank has been offering me since the time of my install.  However if I tweak this to include say two years of electricity prices at 30p (assuming they return to pre crisis levels)  then the IRR leaps to 3.8%.  Obviously more years at these levels increases the savings and the IRR.  

The added battery increases my usage to 60% as well as savings on cheap overnight electricity.  It appears that the IRR on this add on is  about 3%.   

Alnat1

Thanks for all the responses. I can see that many of the differences are due to FIT/SEG, EV/no EV, battery/no battery.

I think for me something around Petriix's "estimate the reduction in overall use from prior to the installation" and using the SVT as comparison might be the simplest way but I do know I've also made energy saving changes since installation too. 

In the end, does it matter? I'm just glad I got it installed before the energy mess we're in now and I know I've saved LOTS already and it will save me LOTS more in the years ahead   

silverwhistle

Alnat1 said:

In the end, does it matter? I'm just glad I got it installed before the energy mess we're in now and I know I've saved LOTS already and it will save me LOTS more in the years ahead   

Basically this. From receiving almost nothing from my emergency funds cash ISA I moved to a situation where I didn't have to worry much about energy bills, although that is not to say no action was taken to use my panels effectively.

How do you cost the savings though? A quick peek reveals a diversion of 9431 units to my immersion since installation, but how should I cost these? Do I take into account that from March to October the boiler isn't used, although it's hardly used outside that period either as I have a wood burner burning scrounged wood from wherever a tree surgeon is working locally.

The bottom line is that although I'm waiting to see the impacts this winter I hope to be able to up my help to the local foodbank from the government assistance I'll be receiving and not really needing.

Coastalwatch

S'funny how we are all drawn into focusing to the 'nth degree on economics seeking to find a satisfactory financially justifiable solution while any environmental benefits almost become overlooked.

It's quite necessary of course that we seek the most cost effective and environmentally sensitive means we can in our journey towards net zero. I wrestled for ages with numerous and varied calculations about how long it would take to show a ROI and often questioning was it all really worth it.

In the end it came down to a simple matter of "Was it the right thing to do"?

Having made that decision it became easier and so determined to make us as energy independent as possible, not for financial gain, but simply to reduce our reliance on FF's.

While our PV generates more kWh's than we consume it doesn't do so when needing it most, in winter, so when the opportunity to take part in crowdfunding a wind turbine arose, when output is traditionally higher in winter, we were keen to take part.

It brought about it's own financial calc's in regard to ROI and various threads on here discussed the matter relentlessly. We'd already made our decision being more than happy for our stake to secure energy at circa 2p/kWh for the next 25 years.

In drawing from the grid at any time I cannot claim we are net zero but in an average year the generation from our clean energy sources into the grid outweigh our consumption by a ratio of around 2 to 1.

As to whether we can claim energy self sufficiency or financial viablility of the path taken to achieve it is very much open to debate, but at least we are comfortable knowing that a lifetimes reliance on FF's has come to an end.

Without doubt the positive contributors on the G&E thread here gave us enormous help along the way and without whom we may never have taken that vital first step!

 

Skintsaver

Personally I wouldn't spend 5k on them I had mine installed under a grant. Before I wouldn't have had them installed and now seeing the saving after 27days I still can't recommend having them. (I happy with mine only due to the grant)

Mines a 2.5kw system 4panels face west 2 face east. Over 27 days I've produced 185kw. Which looking back at the same period last year I've used 42 units less. A saving of £12.18(29p/kwh) for just under a month. When I get a smart meter the remaining 143kw can be sold back at 7.5p/kwh at £10.72. So a total of £23 saving for 1 month. Bear in mind this is probably the month I'll produce the most. Even at £23 every month it'll take 20 years to earn over £5k.

So do I think it's worth it definitely not! 

Add to the future maintenance of changing inverters ect.. Best thing is to buy the most energy efficient appliances turn off what your not using.

Though i wonder what Agile will save me, I need to do estimated calculations for that. 

ABrass

Skintsaver said:

Personally I wouldn't spend 5k on them I had mine installed under a grant. Before I wouldn't have had them installed and now seeing the saving after 27days I still can't recommend having them. (I happy with mine only due to the grant)

Mines a 2.5kw system 4panels face west 2 face east. Over 27 days I've produced 185kw. Which looking back at the same period last year I've used 42 units less. A saving of £12.18(29p/kwh) for just under a month. When I get a smart meter the remaining 143kw can be sold back at 7.5p/kwh at £10.72. So a total of £23 saving for 1 month. Bear in mind this is probably the month I'll produce the most. Even at £23 every month it'll take 20 years to earn over £5k.

So do I think it's worth it definitely not! 

Add to the future maintenance of changing inverters ect.. Best thing is to buy the most energy efficient appliances turn off what your not using.

Though i wonder what Agile will save me, I need to do estimated calculations for that. 

Why would an August be the most productive month?

But yes, tiny systems at high prices will struggle to pay for themselves. That is a system that people should not pay for.

Skintsaver

ABrass said:

Skintsaver said:

Personally I wouldn't spend 5k on them I had mine installed under a grant. Before I wouldn't have had them installed and now seeing the saving after 27days I still can't recommend having them. (I happy with mine only due to the grant)

Mines a 2.5kw system 4panels face west 2 face east. Over 27 days I've produced 185kw. Which looking back at the same period last year I've used 42 units less. A saving of £12.18(29p/kwh) for just under a month. When I get a smart meter the remaining 143kw can be sold back at 7.5p/kwh at £10.72. So a total of £23 saving for 1 month. Bear in mind this is probably the month I'll produce the most. Even at £23 every month it'll take 20 years to earn over £5k.

So do I think it's worth it definitely not! 

Add to the future maintenance of changing inverters ect.. Best thing is to buy the most energy efficient appliances turn off what your not using.

Though i wonder what Agile will save me, I need to do estimated calculations for that. 

Why would an August be the most productive month?

But yes, tiny systems at high prices will struggle to pay for themselves. That is a system that people should not pay for.

August Being a summer month, I'm new to solar so could be supprised by may being the best for example. But August being a summer holiday it's possibly the month I'd use most when at home too.

I must add though I have a flat roof which may beable to have up to 6 panels (definitely 4) which might prove to be cost effective to add to my current system. The inverter rated at 2.5kw but I'll probably only hit 1.5kw at any one time. So that's thoughts for the future... 

But with my current system financially it wouldn't make sense. And only those on FIT tarrifs are benifitting now the most due to already paid back the install cost and bigger electricity costs. 

ABrass

Yep, FITs were really good value to begin with, then dropped to being good value. They are benefiting heavily from their investment.

Even worse they get to say 'I told you so' continuously on repeat for the next two years.