Solar and house battery installation

[johnb80]

In fact, if you’re over 65 you may never see the payback.

That really is not the case. I have explained many times if you look at the true costs and the true savings, payback in my case is less than 6 years, if I compare it to what I would have paid for my energy costs payback is instant because the money saved from energy generated pays the loan used to buy and install the equipment. None of the theoretical numbers here, hard facts from the last 11 months of operation.

My system has generated 5.9 MWh in just under 11 months.

If you cost that at 30p kWh that gives you £1930 per annum. Part of system is a 7kWh battery that saves you £779 per annum add the two together £2709 per year. My loan payments to buy this system are £201.75. So from my perspective the system has paid for itself straight away, my energy bill has reduced from £170 per month to around £130 and it earns me £288 per year. On top of all of that my i3 runs on FREE energy!

 

[DBedford]

That really is not the case. I have explained many times if you look at the true costs and the true savings, payback in my case is less than 6 years, if I compare it to what I would have paid for my energy costs payback is instant because the money saved from energy generated pays the loan used to buy and install the equipment. None of the theoretical numbers here, hard facts from the last 12 months of operation.

Ok, sorry for asking, but as you have explained before, could you in a few lines give us the simple sums to show how.
I’m not the brightest in the pack.

Eg.
For me capital outlay could be £6k (guesstimate) with battery double
Electricity cost 2021 £622 ( 3333kWh)
So payback 10 years

 

[Rolfe]

It also depends on where you are. Right now we have had wall to wall sunshine for a few days and it's forecast to continue for a few more. But we have summers when whe hardly see the sun.

 

[johnb80]

Ok, sorry for asking, but as you have explained before, could you in a few lines give us the simple sums to show how.
I’m not the brightest in the pack.

Eg.
For me capital outlay could be £6k (guesstimate) with battery double
Electricity cost 2021 £622 ( 3333kWh)
So payback 10 years

The capital outlay was just under £12k for my system, I've put the figures in above how it all works finacially. There are some hidden item in there too, we dont use gas for hot water heating any more, that has gone onto immersion from solar / off peak energy which all adds to the savings.

This afternoon, we have full batteries, immersion full heated tank, air conditioning running, washing machine and tumble drier and my neighbour car has been picking some charge from our excess rather than export to the grid. I really cannot fault the system, of the logic in payback, it absolutely works 100% for us and more.

It also depends on where you are. Right now we have had wall to wall sunshine for a few days and it's forecast to continue for a few more. But we have summers when whe hardly see the sun.

Even without sun generation does happen, admittedly at a lower level but it still pays it's way.

This is what May looked like

In addition to this we also exported 240 kWh to the grid.

 

[AK OK]

Oh thats an easy one, I had the choice of pay £270 more per month to my energy supplier of pay £201 per month on a loan for the panels etc. Having gone the panels route the car charging really is free because the panels were purchased to feed the house alone. The system works so well that at no cost it charges my i3 and has done so since February. So smugness level=high, i3 energy =- £0

More analysis required

That really is not the case. I have explained many times if you look at the true costs and the true savings, payback in my case is less than 6 years, if I compare it to what I would have paid for my energy costs payback is instant because the money saved from energy generated pays the loan used to buy and install the equipment. None of the theoretical numbers here, hard facts from the last 11 months of operation.

My system has generated 5.9 MWh in just under 11 months.

View attachment 18050

If you cost that at 30p kWh that gives you £1930 per annum. Part of system is a 7kWh battery that saves you £779 per annum add the two together £2709 per year. My loan payments to buy this system are £201.75. So from my perspective the system has paid for itself straight away, my energy bill has reduced from £170 per month to around £130 and it earns me £288 per year. On top of all of that my i3 runs on FREE energy!

So £40* x12 =£480 + £288 = £768 p.a. "saved"

£12000 cost - straight line depreciated over 10 years £1200 per year (if nothing breaks)

£1200-768 = £432

Er.. what am I missing?

*Assumed a monthly average? as winter will not be as generous as summer...

So £40* x12 =£480 + £288 = £768 p.a. "saved"

£12000 cost - straight line depreciated over 10 years £1200 per year (if nothing breaks)

£1200-768 = £432

Er.. what am I missing?

*Assumed a monthly average? as winter will not be as generous as summer...

Oh I know £12000 in a 4% savings account for 10 years... £17900 less initial £12k is £5900 gain

 

[johnb80]

So £40* x12 =£480 + £288 = £768 p.a. "saved"

Nope, thats not correct. My energy bill would have risen to £430 per month if I hadn't have installed solar + battery.

So £300 per month saving compared to not having solar.

£300 x 12 = £3600 +£288 = £3888 - that will do nicely.

You can analyse it whatever way you want, my bank balance shows the whole picture which reflects all what I've shared above.

 

[AK OK]

Nope, thats not correct. My energy bill would have risen to £430 per month if I hadn't have installed solar + battery.

So £300 per month saving compared to not having solar.

£300 x 12 = £3600 +£288 = £3888 - that will do nicely.

You can analyse it whatever way you want, my bank balance shows the whole picture which reflects all what I've shared above.

YMMV
£430 per month ! In summer?
I used your figures not mine, I see there are now "better" figures.
Well, for winter & the rest of the "assumptions".

Good luck with it

 

[johnb80]

YMMV £430 per month ! In summer?

Thats what my monthly payment to Octopus would have risen to at the end of my 'Go' tariff last year. (13p and 5p).

I used your figures not mine, I see there are now "better" figures.

No the figures were always there merely pointing out the other option of not installing Solar PV.

Well, for winter & the rest of the "assumptions".

Not assumptions at all, historical facts, what has actually happened over the last 11 months.

Good luck with it

We have run through one winter so far and I dont anticipate this coming winter to be any different. Being able to buy electricity at 7.5p kWh is an absolute winner and we can store enough energy to run throughout the day on it. I'm looking forward to getting delivery of our MG5 and consider the V2L aspects being able to integrate it into our system.

 

[AK OK]

We have run through one winter so far and I dont anticipate this coming winter to be any different. Being able to buy electricity at 7.5p kWh is an absolute winner and we can store enough energy to run throughout the day on it. I'm looking forward to getting delivery of our MG5 and consider the V2L aspects being able to integrate it into our system.

£430 per month at £0.3 per kWh is 1433 kWh.
1433kwh /30 is 47.77 kWh per day...
How big's that battery again?

 

[johnb80]

£430 per month at £0.3 per kWh is 1433 kWh.
1433kwh /30 is 47.77 kWh per day...
How big's that battery again?

£430 per month would have been my energy bill i.e. gas and electricity. My current battery capacity is 21kWh usable plus 33KWh in the i3.

 

[AK OK]

£430 per month would have been my energy bill i.e. gas and electricity. My current battery capacity is 21kWh usable plus 33KWh in the i3.

So what do you heat your house with in winter?

 

[johnb80]

So what do you heat your house with in winter?

Depending on outside air temperature either gas, heat pumps or a combination of the two, logic is programmed in Home Assistant to make the decisions.

I'm not where youre heading with all of this, you seem to be challenging whats working for me. I've nothing to gain selling what works for me, I'm not suggesting for one minute anyone should do the same, I'm only reporting my experience over the last 11 months.

 

[AK OK]

Depending on outside air temperature either gas, heat pumps or a combination of the two, logic is programmed in Home Assistant to make the decisions.

I'm not where youre heading with all of this, you seem to be challenging whats working for me. I've nothing to gain selling what works for me, I'm not suggesting for one minute anyone should do the same, I'm only reporting my experience over the last 11 months.

I'm merely querying the detail as I'm not convinced all this stacks up.

How much was the heat pump?

Did you cough up to resize the radiators or is that where the gas usage comes in?

 

[johnb80]

I'm merely querying the detail as I'm not convinced all this stacks up.

How much was the heat pump?

Did you cough up to resize the radiators or is that where the gas usage comes in?

Well I assure you it does stack up, I've monitored my system closely, logged energy consumption every 30 minutes daily courtesy of Octopus Energy. Frankly whether you're convinced or not matters little really to me, if you want to miss out on whats possible that's completely up to you.

It's actual heatpumps, 13 x air conditioning units, one in most rooms including my shed. The original ones were 'Qualitair' units bought from a contractor removing them from temporary SAAB offices some 30 years ago. More recently, over the last 4 years we've replaced them with Mistubishi Heavy Industries Inverter AC Units, varying sizes fro 2.5 kW through to 7.5kW. They can do both heating and cooling with a COP of between 2.5 and 4. I have fitted infra red transmitters where the AC units are installed to control them, setting heating / cooling / temperature etc all from within home Assistant. The gas side hasn't changed other than a new boiler 10 years ago when we extended the house, radiators are the original radiators, no need to increase size because were not using air to water heat pumps although I am looking at some used 11kW Misubishi ECODAN units at the moment with view to installing one to provide constant background heat in the cooler weather. I did try last winter running our gas boiler with low flow temperatures of 40 deg C and had no issues achieving comfortable room temperatures in the house so air to water heatpump should be ok, the other consideration is a Tepeo boiler which would also work nicely with the off peak tariff and allow us to get rid of gas all togther.

 

[AK OK]

Well I assure you it does stack up, I've monitored my system closely, logged energy consumption every 30 minutes daily courtesy of Octopus Energy. Frankly whether you're convinced or not matters little really to me, if you want to miss out on whats possible that's completely up to you.

No need to be defensive.
Now you are starting to sound like a salesman

It's actual heatpumps, 13 x air conditioning units, one in most rooms including my shed. The original ones were 'Qualitair' units bought from a contractor removing them from temporary SAAB offices some 30 years ago. More recently, over the last 4 years we've replaced them with Mistubishi Heavy Industries Inverter AC Units, varying sizes fro 2.5 kW through to 7.5kW. They can do both heating and cooling with a COP of between 2.5 and 4. I have fitted infra red transmitters where the AC units are installed to control them, setting heating / cooling / temperature etc all from within home Assistant. The gas side hasn't changed other than a new boiler 10 years ago when we extended the house, radiators are the original radiators, no need to increase size because were not using air to water heat pumps although I am looking at some used 11kW Misubishi ECODAN units at the moment with view to installing one to provide constant background heat in the cooler weather. I did try last winter running our gas boiler with low flow temperatures of 40 deg C and had no issues achieving comfortable room temperatures in the house so air to water heatpump should be ok, the other consideration is a Tepeo boiler which would also work nicely with the off peak tariff and allow us to get rid of gas all togther.

Sounds like quite a man cave

 

[johnb80]

No need to be defensive.

Well it does seem youre challenging me so being defensive is quite a natural reaction.

Now you are starting to sound like a salesman

Not really, what am I selling here? I dont have any heatpumps / batteries / ZEBS / Inverters for sale, what do I stand to gain to earn the salesman title?

Sounds like quite a man cave

I have enjoyed immensely the last year planning and implementing solar and battery storage. Gluing it all together to work as a whole house system using Home Assistant has been brilliant (I come from a programming background). Tying solar PV and battery charging into the weather forecast has been quite a development, now my system varies the off peak top up based on the weather forecast. This has been operating since mid February and has reduced my off peak consumption based on last years figures.

 

[AK OK]

Well it does seem youre challenging me so being defensive is quite a natural reaction.

Asking questions != challenging.... unless there's something you're worried about bring uncovered
If you hadn't started bragging none of this would have happened probably...

Not really, what am I selling here? I dont have any heatpumps / batteries / ZEBS / Inverters for sale, what do I stand to gain to earn the salesman title?

But claiming others' standard consensus of established payback periods is "wrong" & using seemingly high (& changing) initial figures of what you have paid, were likely to pay & now apparently pay is (still) taking some interpretation & understanding...

I have enjoyed immensely the last year planning and implementing solar and battery storage. Gluing it all together to work as a whole house system using Home Assistant has been brilliant (I come from a programming background). Tying solar PV and battery charging into the weather forecast has been quite a development, now my system varies the off peak top up based on the weather forecast. This has been operating since mid February and has reduced my off peak consumption based on last years figures.

Splendid.
But for the average person on the street - far too involved?

 

[johnb80]

Asking questions != challenging.... unless there's something you're worried about bring uncovered

Hey, anyone if free to come and view my system here, no problem, I have absolutely nothing to hide for any reason.

If you hadn't started bragging none of this would have happened probably...

Why is it bragging reporting my experience as opposed to others quoting theoretical figures and calculations that they have no experience of? Which has greater value?

But claiming others' standard consensus of established payback periods is "wrong" & using seemingly high (& changing) initial figures of what you have paid, were likely to pay & now apparently pay is (still) taking some interpretation & understanding...

I havent changed any figures.

Splendid.
But for the average person on the street - far too involved?

Maybe, maybe not, theres a very good support network for Home Assistant, full of very helpful people that will guide you through the various aspects.

Anyway, I've explained to all concerned how I've arrived at my viewpoint, I don't have to justify my position to you or anyone else, take it on face value or ignore, that's your choice.

That's me done on this topic, make of it what you will.

J

 

[AK OK]

Hey, anyone if free to come and view my system here, no problem, I have absolutely nothing to hide for any reason.


Why is it bragging reporting my experience as opposed to others quoting theoretical figures and calculations that they have no experience of? Which has greater value?

That's to be decided by looking into things in detail... oh well.

I havent changed any figures.

"my payments were going up from £170 per month to £540."

"My energy bill would have risen to £430 per month"

Dunno?

Maybe, maybe not, theres a very good support network for Home Assistant, full of very helpful people that will guide you through the various aspects.

Anyway, I've explained to all concerned how I've arrived at my viewpoint, I don't have to justify my position to you or anyone else, take it on face value or ignore, that's your choice.

Indeed it is.
I've asked questions some of which have generated more questions & apparently irritated you.
If you don't want to divulge any more then that's fine .

That's me done on this topic, make of it what you will.

J

Ok

 

[Gadget Geek]

Hey, anyone if free to come and view my system here, no problem, I have absolutely nothing to hide for any reason.


Why is it bragging reporting my experience as opposed to others quoting theoretical figures and calculations that they have no experience of? Which has greater value?


I havent changed any figures.


Maybe, maybe not, theres a very good support network for Home Assistant, full of very helpful people that will guide you through the various aspects.

Anyway, I've explained to all concerned how I've arrived at my viewpoint, I don't have to justify my position to you or anyone else, take it on face value or ignore, that's your choice.

That's me done on this topic, make of it what you will.

J

I've actually blocked AK OK as I found them deliberately negative, argumentative, and a bit of a troll.

P.S. Also looking at the Tepeo heat battery for the autumn.