My 4.5kWh setup

reklamos

All,

I decided to create this thread and share my experience with my PV setup. I hope it will be useful to others.
It has been exactly one month since everything was installed. The install took whole day(crew of three). The longest time it took to do all the electrical part running the cables from fuse box to inverter. I cannot complain about the work performed so far. BER assessment was also done. The only thing that is outstanding is the SEAI grant.
Here are the details of the setup and some stats for one month:
Solis Hybrid inverter 5kWh
12x375W panels(4.5kWh total), roof facing south so all panels are on one side.
2x3.5kWh batteries
Hot water diverter

Total Stats:
Produced: 511.0kWh
Consumed: 579.0kWh
Fed to Grid: 14.0kWh
Bought: 86.0kWh
Batt Charge: 187.0kWh
Batt discharge: 179.0kWh

Best day: 27.0kWh
Worst day: 7.1kWh
Peak production: 5.5kWh
Self use rate: 61.3%

We have to admit that the summer has been pretty good so far. Most of the days I had battery charged and tank full of hot water. During sunny days the battery is full before 11am. Because there is always someone at home, we try to use as much solar power as possible during the day. This is very important part, you need to adjust to solar productions and have heavy electricity users, when there is plenty of sun. So timed dishwashers, washing machines etc. come in handy unless you can control them remotely.
The battery for me come in handy in the evening and during night time. I do have couple fish tanks and servers with switches running 24x7, so there is constant power demand. If the battery gets full charge during the day and there is enough sun till 5pm, then battery lasts full night and does not drop below 20%, until they start charging again in the morning.

So far I'm liking my setup but not everything is perfect.
1. Although my roof is facing south, it is pretty steep. It does not help that on the west side of the roof there is chimney that casts moving shadow during sunny evenings. I think I do lose some energy because of that but cannot quantify how much. The solution would be to split the panels as the inverter is dual mppt but at the moment all panels are connected to single DC input. Or install optimizers on 4 panels. At the moment I'll leave it like it is and may revisit it later.
2. The inverter does produce a lot of heat during sunny hours and it does not have active cooling. On good days the temperature was climbing to 65 degrees and the heatsink was very hot to touch. It does not help that inverter is in the attic that is facing south, so during sunny days the ambient temperature is warm. To improve cooling I made two shrouds that attach to the top of the heatsink and have two 12V computer fans running. The fans have temperature sensors that are attached to the heatsink of inverter and change the speed based on temperature. Since this was implemented the temperature of inverter never went above 42 degrees, which is good enough for me.
3. Inverter does send stats to the cloud on port 10000. There is a webpage and an app that you can use to see what is going on. It sends stats every 6 minutes so it is not instant and the stats are aggregated. The pages and the app leave a lot to be desired. Although it provides a lot of information the products does not look to be complete or user friendly. Sometimes it stops showing some stats(like production, usage etc). Sometimes the webpages changes to Chinese. I do not really like the provided app or web page, the good thing that on the inverter there is an option to send data to custom server and this is what I'll use. I'm working on Grafana dashboard.
4. I noticed that inverter constantly tried to connect to some Chinese NTP server which was not responding but once I redirected it to known good NTP server it stopped doing that.
5. I'm investigating how the battery is charged/discharged. I do not think that this up and down charge/discharge is good for the life span of the battery. I'd prefer it to have more steady charging cycle. The Advanced settings menu is not locked on inverter so I'm pocking around to see if there is anything can be done about it. If anyone has recommendation, please let me know.

unkel

Nice system, seems to be matched very well to your needs. Well wear!

I wouldn't worry too much about your points 1. and 2. It is what it is and making changes will cost money. Your parts have a warranty. On points 3. and 4. you've already sorted them. Point 5. I would contact your installer and ask them what exact settings did they use. The state of charge of the battery that the system shows is not the real state of charge anyway. There is protection built in at the minimum and maximum levels. If you already know the settings that were programmed, will you share them here? Also what batteries did you get? Pylontech US3000 by any chance?

You have left out the most pertinent detail though. How much did your install set you back in total?

reklamos

Total was 12,979 - the grant
Yes, the batteries are 2x Pylontech US3000
The inverter has a profile for US2000 so this is what is used for battery settings. I can get the settings if needed from inverter.

unkel

That was not a bad price. The benefit of having two of them (and the larger US3000 Pylontech batteries at that) is not just in more storage, it is also in max charge and discharge rate. It means your inverter can charge and discharge the batteries at 37A times 2 as you have the batteries in parallel. That means your inverter can discharge at 3.7kW. So if it is dark and your panels produce nothing but you have juice in the battery and someone switches the 3kW kettle on, it will still all come out of your battery

Some people with a cheaper setup with just a single Pylontech US2000 don't realise that it can only provide 25A, or 1.3kW. So on a sunny day with a 4kwp setup most of your production will go to the grid (or to the diverter). And if someone puts a 3kW kettle on in the evening, almost all of that will have to be bought from the grid

What is the measured system round trip efficiency?

Energy from solar through inverter, into battery charger, into battery, outtov battery, into inverter to end load?

or System Energy In versus Energy Out?

reklamos

Sir Liamalot wrote: »

What is the measured system round trip efficiency?

Energy from solar through inverter, into battery charger, into battery, outtov battery, into inverter to end load?

or System Energy In versus Energy Out?

The round trip efficiency of the battery is 94% but there are other components involved in the chain so that would drop more but I cannot measure by how much. My guesstimate is 80-90%

reklamos

Looks like today is going to be the worst day so far in terms of solar power generation and tomorrow is not looking good either.
I started using https://www.yr.no to try to predict how much power will be generated and this allow to plan the usage better.

reklamos

reklamos wrote: »

The round trip efficiency of the battery is 94%

Indeed I was asking what the measured efficiency from your system is?
Not the contrived datasheet figure. There's a rather large difference usually.
I'm curious for a real world example so I can see what normal operating conditions viability is at.

reklamos

Sir Liamalot wrote: »

Indeed I was asking what the measured efficiency from your system is?
Not the contrived datasheet figure. There's a rather large difference usually.
I'm curious for a real world example so I can see what normal operating conditions viability is at.

I agree that we cannot fully trust the specs sheet but it comes pretty close. Again the only figures I have are coming from inverter. If I look at total charge(187kWh) and discharge figures(179kWh), the figure comes at ~95%.

The batteries are only over month old and time will tell how they will hold.

reklamos

reklamos wrote: »

I agree that we cannot fully trust the specs sheet but it comes pretty close.

I measure them on my systems and find a gulf of difference between Standard Test Conditions (STC) and Normal Operating Conditions (NOC).


STC are climate controlled and optimised load.

reklamos wrote: »

Again the only figures I have are coming from inverter.

Unlikely this is displaying PV DC input so. Probably Inverter Output Only.
The only way to know is to put a clamp-on DC meter on the PV incoming or hardwire an interrupting shunted DC meter.
I've not seen an inverter meter show idle self-consumption at dawn & dusk. Usually, they read 0W when they mean < 0W

reklamos wrote: »

If I look at total charge(187kWh) and discharge figures(179kWh), the figure comes at ~95%.

This is only part of the data.
Charge suggests to me Charger Output so inverter and charger losses not included.
Discharge suggests to me Inverter input.
So if this is how it is 95% is battery efficiency and not system efficiency.



The figure I am most interested in is (Inverter to Load Output / PV DC Input) x 100 [averaged over week]


It's a rather critical coefficient when calculating payback.


Did I tell ya the wan about Tesla PoowerWalls having a 150W continuous heater load in the Winter?




Great job with adding active cooling. You will get an exponential increase in power compared to the self-consumption of the cooling system.

reklamos wrote: »

The batteries are only over month old and time will tell how they will hold.

I would say a very long time. Batteries are quite resilient. It is usually the Charger and BMS that is the Achilles heel of systems.

unkel

Sir Liamalot wrote: »

Did I tell ya the wan about Tesla PoowerWalls having a 150W continuous heater load in the Winter?

Jaysus. I presume only when it is installed outdoors and only when it is cold (sub zero temps) That's 3.6kWh lost on a very cold day. That's more than even a large solar array would produce on most winter days.

How did you find this out?

My bad. It's a 300W heater.

Link.

unkel

PW sounds buggy from quickly reading a few pages of your link. Also did a quick Google and it appears Tesla do not install the PW in living areas. So not inside your house. Sounds like if you don't have a garage and you live in an area where it gets cold, your PW is going to be very inefficient to the extent of being worse than not having one at times :eek:

reklamos

Small update as another month has gone.
I think it was good but I did not hit the levels of July.
The best day produced 25.5kWh and the worst day 4.3kWh

reklamos

Big day today, after 2 month and 3 days, I generated my first MHh.

garo

Well done! I am 26 days in with a 4.8kW system and 383kWh generated.

rolion

Very good rewarding figures.

However,"don't shot the mesenger" but the good days are gone...until next March you will have modest returns with more days just generating to keep the cables warm.

reklamos

My first full electricity bill has arrived since PV was installed.
In 2 months I've imported 187 units, I looked at my bill for previous year same period and it was 987 units. Average daily import is ~3kWh down from ~16kWh
If electricity prices, generation and usage to stay the same, the whole install should payoff in ~10 years. But we all know that prices will go up and generation will fluctuate depending on season/weather. So I estimate it should payoff in ~13-15 years. It may seem a lot of time, but the feeling when I looked at the bill this morning was very pleasant and I hope more pleasant surprises in those 13-15 years.

There are still things that can be improved in the house that would help me to drop consumption a little bit so stay tuned.

unkel

reklamos wrote: »

I estimate it should payoff in ~13-15 years.

If you factor in a 5% or so increase in the electricity price per year and a modest FIT that is likely coming and you got a good deal on the install, then that looks like a realistic figure to me.

At 15 years, that is still a net 7% return on your investment. A lot more than you get with your money on deposit / in any savings account

And of course you are doing the world a big favour being pretty much electricity zero emission with your install

air

The percentage comparison vs a deposit account isn't very fair though as there is no capital left at the end of the PVs lifetime.
On the plus side the savings are like tax free returns

unkel

air wrote: »

The percentage comparison vs a deposit account isn't very fair though as there is no capital left at the end of the PVs lifetime.

That's true, but the return is pretty decent. Let's say your install lasts 20 years (panels last longer, battery shorter) just for simplicity a €6k investment:

Keep your €6k. On a deposit account you get 2% interest (at best), but 30% DIRT is withheld. So net you get 1.4%. With compound interest in 20 years this will grow your €6k to €7,8k

or lose your €6k into a PV install you get a yearly saving of 7% or €420 per year. Put this saving on deposit and with compound net interest of 1.4% after 20 years this is worth €9.3k

That's 20% more! While you obviously also have greatly contributed to the environment. Worthy investment in my book, unless of course you move house before the 20 years are up...

air

Your theory is relying on introducing an additional €420 / year (€8400 total) of capital that has to be earned and deposited to earn the interest.
So I don't think the argument stacks up.

I'm of the it's a faster ROI if I'm just willing to hang the PV at 15° and give any abundance to my neighbours frame of mind.
So much less hardware expense.

PV is super reliable. Decades of service.

garo

air wrote: »

Your theory is relying on introducing an additional €420 / year (€8400 total) of capital that has to be earned and deposited to earn the interest.
So I don't think the argument stacks up.

While I agree the 7% RoI figure is not sound due to the principal not being repaid at the end of the year, this 420€ is indeed real earned savings. You pay 6,000 out of your pocket at the start but then you save 420 every year in electricity bills. That 420 saved can be deposited in a bank and earn interest. So the 9.3k vs 7.8k comparison after 20 years is valid.

garo

PS: Finally got the CT sensor connected to the right wire today. It was connected to one out of two wires coming out of the main fuse so was ignoring any power drawn on half the circuits. Washer dryer microwave etc. Nice to see the app now showing real power draw and not some made up ridiculous number. Expect that daily import will also go down from the 5.5 units it was averaging.

rolion

reklamos wrote: »

My first full electricity bill has arrived since PV was installed.
In 2 months I've imported 187 units, I looked at my bill for previous year same period and it was 987 units. Average daily import is ~3kWh down from ~16kWh

There are still things that can be improved in the house that would help me to drop consumption a little bit so stay tuned.

As being your first bill with PVs let me "congratulate" you .
May i suggest to wait for 12 months and then you get the figures corect as from todays until end of March the system will not perform as good during summer hot bright days.

air

garo wrote: »

That 420 saved can be deposited in a bank and earn interest.

It can't, you're completely misinterpreting the financials.
I can see where you are coming from from a cashflow perspective but from an ROI perspective you're completely wrong.

Take the following simplified scenario:
Electricity supply cost is €400 per year
PV system of some nominal capacity costs €6000 and will cover 100% of consumption. It's usable lifetime is 20 years. Zero residual value.


Option 1. You buy PV to supply your energy
Pay 6000 up front, saving of 400/ year

After 20 years you have received 8000 back in savings (NB. Zero cash is created for reinvestment)
Compound annual rate is 1.45% and that is all. There is no cash generated for reinvestment elsewhere, you've simply eliminated a liability.

Option 2. You keep 6000 in the bank and pay 400/annum for electricity.
Invest your 6000 at 1.45% CAR after tax

After 20 years
8,0000!!!

The difference is you're tied in for 20 years with the PV and any unforeseen maintenance or repairs reduce the return.

High frequency inverters lasting 20 years?
All my days I have not seen one do that.

Seen a few transformer jobs last that long alright. Installers and manufacturers don't like them though, expensive to ship, expensive to build, heavy to mount to walls every day.

reklamos

rolion wrote: »

As being your first bill with PVs let me "congratulate" you .
May i suggest to wait for 12 months and then you get the figures corect as from todays until end of March the system will not perform as good during summer hot bright days.

Oh I know that it is downhill from now on till spring. I think majority who installed PV did it not because of ROI. The ones who think they'll save a fortune, were fooled by sales/marketing. Look what is happening in UK already. We're in wrong country to make any substancial gains from PV power for start.
I'd say probably in 10 years I'll have something added or replaced in the whole setup which will eat up additional cash but I don't mind. I like tinkering with new stuff and if it saves as few $, I'm happy with that.

unkel

air wrote: »

It can't, you're completely misinterpreting the financials.
I can see where you are coming from from a cashflow perspective but from an ROI perspective you're completely wrong.

Not at all. You are either trading your 6000 for a cash back of 400 a year. You should put this cash back in the bank where it will compound interest. Or you keep your 6000 in the bank and receive compound interest on top. The first option has a higher return (but also more risks)

Sir Liamalot wrote: »

High frequency inverters lasting 20 years?

It was for simplicity sakes. Panels (including their expensive labour for install) last 30+ years. Battery and inverter maybe a bit over 10 years but can be cheaply replaced without much labour. Overall say a weighted money average of around 20 years

Depends on the inverter. Ac coupling "hybrids" and DC battery jobbers are north of 1k€. It's a fair chunk of the investment. I'd say 10 years and they won't owe you anything.
For simplicity I count 2 inverters over 20 years (or Studer).

unkel

Sir Liamalot wrote: »

For simplicity I count 2 inverters over 20 years

Sure. But then also count only a bit over half of your roof installed panels cost over 20 years. See where I'm coming from? I reckon for a simplified maths exercise like we are doing here it is not unreasonable to give the whole system a weighted average life of around 20 years. Or 17 or 23. My point about bigger returns on a PV system compared to a savings account still stands.

BTW you don't know where I can score a free / cheap waterproof enclosure big enough for 16 lead acid batteries, do you? My source is not coming through for me and I have used up all the patience I have in me in waiting for several months. I want to get it up at the latest by next February

Not really the panels i bought 20 years ago lasted 20 years I'm not saving money by not buying them twice. Payback over 20 years = return versus cost incurred over 20 years.

I do it for the electrons. Payback is air quality and it working as well as it can.
I just reference it as a common denominator. People understand 1k€ easier than 1kW.

Just cover the terminals AGM are sealed. Unless you have a box to tick.

Car roof box?

air

unkel wrote: »

Not at all. You are either trading your 6000 for a cash back of 400 a year.

Are you assuming a FIT income of 400 a year (in addition to bill reductions)?
That's the only angle I can see your logic working perhaps.

Having said that, even for myself I'm on the FIT, but it gets credited to my supply account and my annual bill isn't totally covered by it. No free cash is generated for reinvestment.

I don't understand where you are getting €400 "cash back". There's no cash back, the return is in the form of a reduction in your previous liability.

garo

air wrote: »

Are you assuming a FIT income of 400 a year (in addition to bill reductions)?
That's the only angle I can see your logic working perhaps.

Having said that, even for myself I'm on the FIT, but it gets credited to my supply account and my annual bill isn't totally covered by it. No free cash is generated for reinvestment.

I don't understand where you are getting €400 "cash back". There's no cash back, the return is in the form of a reduction in your previous liability.

air this is getting a bit silly now. If you install a PV system you get a reduction in your electricity bill. That’s extra money in your pocket so same as earning 400€ a year. If you didn’t have a PV system you would have 6k extra in the bank earning interest but you would be paying 400€ a year more on electricity bills so that will eat away into your 6000€. We are trying to figure out where the breakeven point is ignoring inverter life, possible maintenance etc. If you wanted to do it properly you would assume a discount rate equal to the risk free rate etc. For instance that’s how bond prices are calculated. So you have to think of the PV system as a bond that pays an annual coupon of €400 but doesn’t pay back any principal. But that’s all pretty complicated and before that you have to agree that even according to your calculations after 20 years we are breakeven?

Think about this another way. In your example let us assume you have €6000 to cover your electricity costs for 20 years. If you install a PV system you are home free - assuming no maintenance and inverter replacement. Agree? Now assume you put that €6000 in a bank earning 1.45% after tax. At the end of the first year when the first electricity bill of 400 comes due where do you get that cash from? From your €6087 in the bank (87 is 1 yr interest). So at the start of year 2 you have €5687 left and you earn interest on that and not on 6087. So you run out of money before your 20 years are up.

That’s how mortgages are calculated. Anywhere where there is a regular payment and an interest in the picture you have to take both into account fairly.

air

I agree with your post 100% Garo but unkel is arguing that 400 a year is generated in actual cash which can be reinvested in an interest bearing account further improving the case for PV. This is absolutely not the case.

As it happens the sample figures are pretty close to my own PV investment and return. I "save" about €400 a year between FIT and self consumption but ZERO cash is generated that can be reinvested.

This is the only point I'm making and I'm pretty sure of my figures as I've been executing the exact scenario for several years!

air

unkel wrote: »

or lose your €6k into a PV install you get a yearly saving of 7% or €420 per year. Put this saving on deposit and with compound net interest of 1.4% after 20 years this is worth €9.3k

This is the crux of what I'm arguing against.
You make the saving yes, but that saving is the return, there is no further cash generated which can be put on deposit!!!!

garo

I think this is just a misunderstanding. The 400€ you save is equivalent to earning 400€ more and that money should be calculated as earning interest if you are comparing it with the 6000€ earning interest. I don’t interpret unkel’s post as double-counting. You can do the comparison in multiple ways but the right way is for both sums to earn interest and be discounted by the risk free rate because €1 today will not have the same value as €1 20 years from now.
Suffice to say something between 15-20 years is a good estimate of the current payback period.
There’s a lot of uncertainty. We don’t know how long the hardware will last. No one can predict if and when the FIT will come and at what rate and how electricity prices will go up or down. So to try to pin down the exact payback period is a fool’s errand.

garo

air wrote: »

This is the crux of what I'm arguing against.
You make the saving yes, but that saving is the return, there is no further cash generated which can be put on deposit!!!!

Disagree here. The saved money can be put into an interest bearing account. The whole basis kf compound interest is that you earn a return on the return.

air

garo wrote: »

Disagree here. The saved money can be put into an interest bearing account. The whole basis kf compound interest is that you earn a return on the return.

We'll have to agree to disagree I think.

Without PV your annual cash flow is like this:
Year 1:-400
Year 2:-400
Year 3:-400
...
Year 20:-400

With PV it's :

Year 1: 0
Year 2:0
Year 3:0
...
Year 20:0

There is no positive cash return generated that can be reinvested in an interest bearing account.

This is very close to my current setup. At a guess I've about €5k spent and my annual bill is about €100 (rough figures).
I'm saving ~€400/annum which I'm happy with - tax free return and panels should last another 15 years easily, FIT could disappear any time though.

From a cash flow perspective I'm up €400/ year, but like I keep saying, this is on the basis of having eliminated this amount of annual liability.

I do not have €400 free cash generated that can be invested or spent on anything else

KCross

air wrote: »

I don't understand where you are getting €400 "cash back". There's no cash back, the return is in the form of a reduction in your previous liability.

air wrote: »

I agree with your post 100% Garo but unkel is arguing that 400 a year is generated in actual cash which can be reinvested in an interest bearing account further improving the case for PV. This is absolutely not the case.

As it happens the sample figures are pretty close to my own PV investment and return. I "save" about €400 a year between FIT and self consumption but ZERO cash is generated that can be reinvested.

But the saving is in your current account. Its money you have, which you now dont have to spend as a result of investing in PV so its like a pay rise if you will.

air wrote: »

This is the crux of what I'm arguing against.
You make the saving yes, but that saving is the return, there is no further cash generated which can be put on deposit!!!!

air wrote: »

From a cash flow perspective I'm up €400/ year, but like I keep saying, this is on the basis of having eliminated this amount of annual liability.

I do not have €400 free cash generated that can be invested or spent on anything else

Your issue seems to be around the use of the word "cash back" and "cash generated".

If I have a €400/yr liability that has to be paid out of my current account and now I dont have to pay that anymore, surely that means I have €400 more in my current account each year... yes? Thats the "cash back" its just not in the form of a cheque in the post.

Just transfer that €400 at the end of each year out of your current account into a deposit account. Whats the issue with that logic?

Are you really only arguing about the use of the word "cash back"?

air

KCross wrote: »

Just transfer that €400 at the end of each year out of your current account into a deposit account. Whats the issue with that logic?

My issue with tha logic is that it forces me to pay €400 a year, which is what the PV was put in to eliminate.
Plus it's 400/year that I have to contribute in addition to the capital cost of the PV.

It's like a bank telling me that they'll give me 400/year interest on my €6000 but that if I also deposit an additional €400/year to the account I'll have even more at the end of the term!

KCross

air wrote: »

My issue with tha logic is that it forces me to pay €400 a year, which is what the PV was put in to eliminate.
Plus it's 400/year that I have to contribute in addition to the capital cost of the PV.

It's like a bank telling me that they'll give me 400/year interest on my €6000 but that if I also deposit an additional €400/year to the account I'll have even more at the end of the term!

ok, I agree its a little unorthodox and as you said its not allowing for the fact that there is alot more risk (failing inverters etc) but if you are looking at the end result after 20yrs the logic is sound.

I'm not agreeing that I'd use the same logic myself when investing in PV but in the simplistic scenario ye are debating it is valid if you look at what money is in your deposit account at the end of 20 years.

air

garo wrote: »

Disagree here. The saved money can be put into an interest bearing account. The whole basis kf compound interest is that you earn a return on the return.

What money? There is no money to invest.
I can't invest a reduced liability.

You're proposing introducing additional capital every year which is nonsensical in terms of evaluating the original investment.

garo

So you take the present value of €6,000 on one hand and the present value of a stream of €400 annual payments you would have to make otherwise for 20 years. Easy enough to do in Excel. Use a discount rate of whatever you wish and you will see that PV comes out on top for all discount rates under 2.9%. So unless you are getting 2.9% tax free on your €6,000 you are better off going PV in this limited scenario.
This is a pretty routine calculation. Every bond trader makes it as does every mortgage calculator.

KCross

air wrote: »

What money? There is no money to invest.
I can't invest a reduced liability.

You're proposing introducing additional capital every year which is nonsensical in terms of evaluating the original investment.

Why cant you invest the savings? Its a choice surely... you either spend it on living expenses or invest it. Its a choice.

air

That sounds realistic and a decent enough rate of return.
The thing to remember though is that the 400 return is locked in and offset against the annual energy supply liability.
It's not like a regular return on an investment.

Any future increases in energy prices should help the ROI, as will eeking out additional life from the installation.

Expected lifetimes of panels are continually being revised upwards from what I've seen.

Ireland has better prospects for PV lifetime than many parts of the world due to reduced thermal cycle ageing.

I also enjoy the feeling of being hedged to some extent against any future energy price hikes and indeed supply interruptions since I can run off grid when required.

unkel

Sir Liamalot wrote: »

Just cover the terminals AGM are sealed. Unless you have a box to tick.

Car roof box?

Completely forgot they are AGM

So a garden box like this would be more than sufficient so:

Linky


Provided of course I can fit the batteries in. The one I linked to is not wide enough for a 4 battery in series string

air

KCross wrote: »

Why cant you invest the savings? Its a choice surely... you either spend it on living expenses or invest it. Its a choice.

I can't invest the savings because there is nothing to invest.
Imagine a situation where I have no costs (other than electricity) or income. I've 6000 at the start.

At the start of the 20 years I have the option to either pay 400/ year for electricity as I go or invest in PV that will deliver all my electricity.

I put 6000 into the PV and now have no income or capital but no costs.

The PV is not delivering further income that can be reinvested elsewhere.

KCross

air wrote: »

I can't invest the savings because there is nothing to invest.
I can if I want choose to invest more of my income as a result of

Splitting hairs.