Worth going solar?

[Dope]

Hi everyone

 

I am planning on going solar, but I don't know if it will be worth it in my case, as our monthly electricity usage is around 400kWh. Will it be worth the expense of getting a solar geyser and some PV panels, batteries and inverter?

 

I had a look at prices and they look like this:

Inverter - R 9000

Solar Geyser - R4000

Some solar panels - R 7000

4 Deep cycle batteries - R8000

 

I can do most of the install myself as my dad is a plumber and my brother an engineer, so I can get them to do most of the work for me

 

But is spending R28 000 really going to be worth it, if my monthly bill is only around R500? Any advice would be greatly appreciated.

 

Regards

[Pony]

How about a backup battery for critical loads? lights/tv/hairdryer.

P

[Dope]

How about a backup battery for critical loads? lights/tv/hairdryer.

P

I currently have a small modified sinewave inverter for my lights and all my electronic equipment, but I want to replace it with a pure sinwave inverter, as the current one does not properly power my TV and i thought that if I get a new inverter I might just as well get one that does solar.

 

And that got me thinking of going more onto solar, but I need some advice on if it would be worth the expense?

[Pony]

With such low power use, my personal recommendation would be to spend on a solar geyser and make it as efficent as possible.

This should save you atleast 25% I feel. Use a bit of budget on a pure sine wave inverter for your electronics, as they dont run of modified sine wave and could dammage them.

1) solar geyser

2) new inverter for battery backup.

However if solar is a hobby and brings your joy then why not. If so a small hybrid inverter might be a good starting point as then you have replaced the inverter as well and serves as a platform for the future. What you guys think?

P

[Dope]

With such low power use, my personal recommendation would be to spend on a solar geyser and make it as efficent as possible.

This should save you atleast 25% I feel. Use a bit of budget on a pure sine wave inverter for your electronics, as they dont run of modified sine wave and could dammage them.

1) solar geyser

2) new inverter for battery backup.

However if solar is a hobby and brings your joy then why not. If so a small hybrid inverter might be a good starting point as then you have replaced the inverter as well and serves as a platform for the future. What you guys think?

P

I was thinking of getting a Axpert 3kW inverter, as it seems to meet most of my needs, its cheap and can be used with solar as well.

 

Will definately be getting a solar geyser, just need to decide on ET or flat plate. Any recommendations?

[Carl]

I would recommend a good quality flat plate collector in a Thermosyphon configuration.

Characteristics that I would look for in the flat plate collector are as follows:

1) Copper risers & header manifolds

2) Copper or aluminum absorber 

3) Selective or semi selective coating applied to absorber

4) Preferably ultrasonic welding where the risers connect to the absorber

5) Iron free tempered glass or anti reflective coated glass as the cover

6) Strong extruded aluminum profiled casing

7) Mineral or glass wool as the back insulation.

[DeepBass9]

I was thinking of getting a Axpert 3kW inverter, as it seems to meet most of my needs, its cheap and can be used with solar as well.

 

Will definately be getting a solar geyser, just need to decide on ET or flat plate. Any recommendations?

 

ET are much better that flat plate. I have both and the tubes heat up way quicker than flat plate.

[Eugene]

I was thinking of getting a Axpert 3kW inverter, as it seems to meet most of my needs, its cheap and can be used with solar as well.

 

Will definately be getting a solar geyser, just need to decide on ET or flat plate. Any recommendations?

Did some matching up of specs of YGE 60 cell pv panels to Axpert (PWM) KS 3Kva.

6 x 245W in parallel, @ Pmax = 30V, 49.68A

Decided it's not viable.

[SilverNodashi]

Why not rather run two strings of 3 panels in series instead?

[Eugene]

Why not rather run two strings of 3 panels in series instead?

Because the Max Power Voltage is 30-32 for the KS, can be done with the MKS which has a MPPT charge controller.

[pwallace10]

Hi Eugene

 

I have just finished my Solar PV installation, the "sparky" came around on Tuesday to replace my old DB with a new one, as my luck would have it we will now have a week of rain...

 

Worth or not is a different for each of us, it depends on ....and I hate to say it... what you want to spend..

 

I have been fiddling with solar for about 4 years now, it started as a hobby fiddle around thing but became more real once load shedding hit us. Initially i just had PV panels, a charge controller and LED lights, then I modified an old UPS to give me AC for the load shedding periods. That became a mess with extension leads everywhere for 2 hours while Eskom did their thing.

 

Towards the end of last year I started looking for a better solution, sadly everything in South Africa was just too expensive, ironically enough the place I had been buying my solar stuff was called "sustainable" but their pricing made solar very un-"sustainable".

 

If you speak to a solution provider and they will sell you a solution based on some wild idea of 3 days

[Albo]

HI If your dad is a Plumber you can construct your own solar water heater easily, (modify the pipe work on yr existing geaser) and it you can raise your geaser make it a simple Therom Syphon system (no valves or things to go wrong). If you are in a frost zone you need to take this into account. This will reduce your main load a lot, and maybe give you a realistic pay back on a smaller system that overcomes load shedding irritation. 

A

[Bobster.]

I use under 500 kw/h most months. I have a more expensive solution than you, including 10 kw/h of lithium battery. 

Rough calculations show that if electricity goes up 10% a year, the system will break even in terms of the electricity bill in about 10 years.

Since I'll be due for new batteries then i expect to just break even in terms of the bill. 

But there are soft value issues as well. My deep freeze won't lose its contents, the security system stays up, we are untroubled by load sheds... 

So depending on how you weight the indirect benefits you can justify the outlay 

[Richard Mackay]

33 minutes ago, Bobster said:

But there are soft value issues as well. My deep freeze won't lose its contents, the security system stays up, we are untroubled by load sheds... 

So depending on how you weight the indirect benefits you can justify the outlay 

This thread made a 5 year jump but amazing how the questions are still the same.

I'm convinced that here in SA the driving force is the intermittent availability of the grid. So the solution is to address what you need to keep running during power outages. But we get ambitious and start dreaming about going off grid..

There's a massive difference between the two so it's a good idea to think long and hard as to what you actually want (with the power on and if you can when the lights go off as well!)

[mmacleod]

15 hours ago, Richard Mackay said:

This thread made a 5 year jump but amazing how the questions are still the same.

I'm convinced that here in SA the driving force is the intermittent availability of the grid. So the solution is to address what you need to keep running during power outages. But we get ambitious and start dreaming about going off grid..

There's a massive difference between the two so it's a good idea to think long and hard as to what you actually want (with the power on and if you can when the lights go off as well!)

100% - its much cheaper and much faster in terms of ROI to take only a portion of the household  that you need off grid, than to go full blown solar.
However there tends to be some kind of allure that sucks people immediately into taking an all or nothing approach. This is why solar then has a reputation as being incredibly expensive.

[Bobster.]

I'm not off grid. But since my system started running reliably we have have always had power in the house with only a few circuits losing power. 

The way I put it is that most days we generate most (96 to 97%) of our own power and the lights, security system, fridges etc always stay on. 

A prolonged stretch of bad weather simultaneously with a long outage would see us eventually shut down. That's long odds though not impossible. 

So we need to stop thinking in binary terms of being at Eskom’s mercy or going off grid. There's a middle ground that will give you good continuity and save you a good whack

Edited March 7, 2020 by Bobster

[Pietpower]

51 minutes ago, mmacleod said:

100% - its much cheaper and much faster in terms of ROI to take only a portion of the household  that you need off grid, than to go full blown solar.
However there tends to be some kind of allure that sucks people immediately into taking an all or nothing approach. This is why solar then has a reputation as being incredibly expensive.

What is the difference if you spend R50,000 and save R400 a month or if you spend R100,000 and save R800 per month.  The ROI should be exactly the same?

[mmacleod]

10 minutes ago, Pietpower said:

What is the difference if you spend R50,000 and save R400 a month or if you spend R100,000 and save R800 per month.  The ROI should be exactly the same?

Well sure in a completely fictitious example where spending double the money gets you exactly double the savings the ROI is exactly the same.
Well not exactly, because it assumes the costs to acquire the capital are the same - which isn't guaranteed, but anyway...

In reality however the things being talked about are not linear.
A system that attempts to meet 100%+ of demand costs more than a system that is designed just to handle the low hanging fruit.

[PJJ]

51 minutes ago, Pietpower said:

What is the difference if you spend R50,000 and save R400 a month or if you spend R100,000 and save R800 per month.  The ROI should be exactly the same?

The problem with going off grid is generating that last say 20% of your needs.

If you stay on the grid, with a decent battery bank you can generate 50-80% of your power needs without blowing the kitty.

But that last 20% gets exponentially more expensive to supplement, its definitely not linear.

Also like Macleod pointed out, financing, you might have R50K in savings somewhere you can raid for a nice on-grid system, but R100K+ would see you having to finance a portion (or all for that matter) and capital is a finite resource. 

[Pietpower]

22 minutes ago, PJJ said:

Also like Macleod pointed out, financing, you might have R50K in savings somewhere you can raid for a nice on-grid system, but R100K+ would see you having to finance a portion (or all for that matter) and capital is a finite resource. 

If you have R50k you could invest it in your bond and 'earn' interest on it.  Or if you take another R50k from your bond then you pay similar interest.  Cost of the capital is all about the same unless you go take out a personal loan or something.

But I see I missed the point above. It is about going 100% off grid vs going partially off grid.  Yes the former is going to cost a lot more than the latter because you need to install more than you need for those rainy days.

  

22 minutes ago, PJJ said:

If you stay on the grid, with a decent battery bank you can generate 50-80% of your power needs without blowing the kitty.

Currently I cover about 90% of my needs.  But I spent some effort to try and make use of the most of the solar power available or to match the solar system and the usage.

 

PS I think a smaller system like a 3KVA can actually have a lower ROI than a 5kVA system if your stay connected to the grid.  When you install a smaller system you remove much of the larger loads such as say a kettle or geyser or dishwasher etc.  Now your load on the inverter suddenly drop to say 200-500W and you are not utilising the capacity of the inverter and getting a lower ROI.

[Gerrie]

18 hours ago, Richard Mackay said:

I'm convinced that here in SA the driving force is the intermittent availability of the grid. So the solution is to address what you need to keep running during power outages. But we get ambitious and start dreaming about going off grid..

I agree with Richard for me one of the biggest reasons to go solar was the fact that the grid can fall away at any time for who knows how long. My freezer was unplugged and moved to the garage for a couple of years because I did not want to loose the contents again and again.  The inconvenience of not being able to stock up my freezer made me realize the expensive cost of having to buy food on a daily basis plus the time wasted running to the shops for basic things that could be in a freezer. Now with the solar power, my deep freeze is stocked again because I have that guarantee that the odds of losing it’s contents due to Eskom is very slim. So the saving on groceries alone is a huge saving.

 

 

[Gerrie]

19 hours ago, Richard Mackay said:

But we get ambitious and start dreaming about going off grid..

That’s me, not there yet but getting closer. My pre-paid meter is struggling to deplete those units that once had to be topped up regularly and at the most inconvenient times. I have been stretching my last 20 Eskom units for the last couple of days and am actually looking forward to load some new units tomorrow that can be stretched again to see my next best record. I installed 2 extra panels last month so things keep improving.

[FixAMess]

We also need to factor in the possibility of you selling your home in the next 5 years. With a decent PV system in place you should be in a better position to sell. Also with the impending collapse of the ZAR, PV is going to become, relatively, much more expensive to buy... You win by installing now, ZAR relatively strong, savings on future  Escom price increases and the value of your biggest asset, your home, will increase.. 

[Richard Mackay]

5 hours ago, mmacleod said:

100% - its much cheaper and much faster in terms of ROI to take only a portion of the household  that you need off grid, than to go full blown solar.
However there tends to be some kind of allure that sucks people immediately into taking an all or nothing approach. This is why solar then has a reputation as being incredibly expensive.

Walk me through this:

1) How do you calculate your ROi?

 2) I was under the impression if you only power some of your load with a RE system this then cannot be expanded to cope with the next phase forcing you into upgrade your system..

[PaulF007]

Wow been a while since this one has came up.

Ok here is one way to do it and this is from a pure $$ point of view in South Africa.

Lets say you would like to do a basic setup with an Axpert. 

Thumb suck as I am to lazy to check for prices but it should set you back about R 150 k 
You will need to adapt your house hold consumption so that it fits n with the 4kw system as you will fry your batts if you dont.  
Now take your household consumtion after you have made the changes - Solar geyser , gas stove , low watts fridge , freezer and lights. Dont forget the TV ( These should also be added to you Total investment)

Now lest look at the Value of you money - R 150 000 x 9% =  R 13 500.00 / 12 = R 1 125 per month. 
Lett say current Eskom rate is R 2.50 per unit - R 1 125/2.5 = 450 unis

So if your current consumption is less than 450 per month after you made your changes you will , in theory , never make back your money as the interest alone covers the units alternatively if you use more that that you should be good to make you money back over the term of about 10 years. Keep in mind that you are paying now and should not need to spend any thing over the rest of the term.

As a side note I did do a much more comprehensive calculation a while back and it should be here somewhere on the forum but this should at least give you one principal that you could follow. 
Keep in mind that this is from a pure Cost vs Consumption.If you add loss of business as a result of Load shed that calculations will be much more subjective.

Another note - depending on what system you add  ,a solar system could even be a liability if you were to sell your house ....