90% off-grid vs fully off-grid rooftop solar system price comparison

[Jan]

R100,000 upgrade to say goodbye to Eskom's tariff hikes

South African households with grid-tied solar power systems will have to spend roughly another R100,000 to upgrade their systems to be fully off-grid and avoid Eskom's tariff hikes.

The power utility applied to the National Energy Regulator of South Africa (Nersa) for significant electricity price adjustments in 2025.

 

[BBSA]

Actually you can just get a generator as a backup to account for long periods of inclement weather with low solar generation.

 

[Hanno Labuschagne]

Actually you can just get a generator as a backup to account for long periods of inclement weather with low solar generation.

I wanted to include a mention of that, but things started to get a bit long. Definitely an option for some, but many complexes and estates don't allow them at all. Also, you have to factor in refuelling and maintenance costs.

 

[BBSA]

I wanted to include a mention of that, but things started to get a bit long. Definitely an option for some, but many complexes and estates don't allow them at all. Also, you have to factor in refuelling and maintenance costs.

I guess it also depends on where you are. I live off-grid in Gauteng and only fire up my generator a couple of times a year.

 

[RaptorSA]

I wanted to include a mention of that, but things started to get a bit long. Definitely an option for some, but many complexes and estates don't allow them at all. Also, you have to factor in refuelling and maintenance costs.

Was going to say this.
Even people I know who have a generator have mostly stopped using it due to the pain of maintenance, noise etc.

As for the stated +-R100K in the article... that sounds about right, my small system (current generation between 200-300kWh per month) would have to double in size AND I'd need to sort out water heating which is currently being done with "unused power" from my solar system, obviously inefficient.

Was going to wait but Citipower in JHB is crumbling so apart from the cost increases there's that.

 

[Zellephant]

Has MyBB gone from taking money from Monochoice to scare people into sticking with DSTV to now taking money from EksDom to scare people into sticking with them and not cutting their grid ties?

These prices being quoted seem a bit outrageous…. And would also like to see their per component cost breakdown.

I have just put in an off grid system designed to provide 15kwh/h per day (450kw/h p month). And we are planning to go fully off grid soon, if Eskom gets their way with regards to tarriff increases. If that happens, we will add an extra battery, but nothing more. So far my system of 6x550w panels, 5kw/h battery, 8KW invertor, installed cost me R42k, basically half of the quoted price for a similar system in this article.

I also can’t see why you need to go 5x on the batteries and 3x on the panels in order to complete cut grid ties? We are planning on adding an extra battery in a few months when budget allows, and that should have us covered - even in the Western Cape with long spells of rainy weather in winter.

Will also just run the generator to recharge the batteries if the need arises. Even from completely flat, a 5Kva gennie will recharge the batteries in full in about 3 hours, costing a few litres of petrol.

 

[Pythonista]

It's quite difficult to go fully off-grid here in Cape Town, especially if you live in a "leafy" suburb with high trees. Having done my first full winter on 16x600watt panels (8 x north + 8 x east facing) and 10 kwh battery, I can conclude that to get to 99% off-grid, I'd need at least another 10 kwh battery. The single biggest power consumer is heating (geyser and stove). I already cook on gas, so in my case it's just the geyser. If I put a gas heater onto my "guest" bathroom, I think I could almost get to 99.9%. Just to spite Eskom, I am definitely considering this.

 

[shogun]

Nah, this looks pretty spot on actually. For the 900kWh system, choosing different components (Sunsynk 12kW single phase inverter (R38K, 3 x Volta Stage 4 batteries R120K, 24 Jink 560W panels R35.8K, Axe struct mounting @ approx R28K, and installation and wiring +/- R40K, that would come in a little cheaper for the same spec (could go even cheaper with SVolt batteries), but to be fair as a rough guide where you are multiplying up for 3 similar systems, this is only about 10-20% more expensive than you can get).

That being said, you are generating a LOT more than 900 kWh on average with that system in a month (I assume that's 900kWh in the worst case, winter)... with 15.6kWp panels, I'm generating 2500kWh in December. If I do half that in winter I'm still going to be over 900kWh.

 

[shogun]

It's quite difficult to go fully off-grid here in Cape Town, especially if you live in a "leafy" suburb with high trees. Having done my first full winter on 16x600watt panels (8 x north + 8 x east facing) and 10 kwh battery, I can conclude that to get to 99% off-grid, I'd need at least another 10 kwh battery. The single biggest power consumer is heating (geyser and stove). I already cook on gas, so in my case it's just the geyser. If I put a gas heater onto my "guest" bathroom, I think I could almost get to 99.9%. Just to spite Eskom, I am definitely considering this.

Yeah, it's the batteries more than the panels. I've got a 14.2kWh battery, and I'm about 5kWh short of where I need to be in the middle of winter. In summer my SOC drops to about 50% over night. I'm going to get a second 14.2 kWh battery before winter, then I'd easily cut the cord if the SSEG feed back didn't cover the increased rate. The panels are the cheap part... so I have 15.6kWp of those (14 x 560W east facing, 14 x 560w west facing), and my 14.2 kWh battery is full by 10am... the nice part is that in the middle of the worst winter cold front in pouring rain, the panels still generate about 2-3kW... so no generator needed.

 

[NinTniN]

How difficult is it to get the municipality to disconnect the power to my house once I installed the correct size solar system?

 

[Zellephant]

Yeah, it's the batteries more than the panels. I've got a 14.2kWh battery, and I'm about 5kWh short of where I need to be in the middle of winter. In summer my SOC drops to about 50% over night. I'm going to get a second 14.2 kWh battery before winter, then I'd easily cut the cord if the SSEG feed back didn't cover the increased rate. The panels are the cheap part... so I have 15.6kWp of those (14 x 560W east facing, 14 x 560w west facing), and my 14.2 kWh battery is full by 10am... the nice part is that in the middle of the worst winter cold front in pouring rain, the panels still generate about 2-3kW... so no generator needed.

out of interest How many people in your household? Assuming your battery is going into the night fully charged in summer, what is drawing +-7kw/h during the evening?

As I said I only have a 5kw/h battery. We currently have our geyser on a timer, so it only runs in daylight hours. Overnight our SOC hardly ever goes below 50%, including running the dishwasher almost every night and often a load of laundry gets done overnight as well. (For now, we switch back to Eskom if we use the oven at night, but once I double up the batteries we shouldn’t need to do that anymore)

 

[Pythonista]

How difficult is it to get the municipality to disconnect the power to my house once I installed the correct size solar system?

I may be wrong on this, but even if you disconnect, the municipality is still entitled to charge an "availability fee". This would be for the cost of infrastructure to put a cable running next to your property. This capability adds to the value of your house. Unless you sold to a like-minded "off-gridder", you would struggle to sell a house with no ability to run electrical appliances.

 

[BBSA]

I may be wrong on this, but even if you disconnect, the municipality is still entitled to charge an "availability fee". This would be for the cost of infrastructure to put a cable running next to your property. This capability adds to the value of your house. Unless you sold to a like-minded "off-gridder", you would struggle to sell a house with no ability to run electrical appliances.

I'd totally shell out more cash for an off-grid house.

 

[B-1]

How difficult is it to get the municipality to disconnect the power to my house once I installed the correct size solar system?

Looks like they make it as hard as possible. Its easier to go prepaid for most areas.

 

[shogun]

out of interest How many people in your household? Assuming your battery is going into the night fully charged in summer, what is drawing +-7kw/h during the evening?

As I said I only have a 5kw/h battery. We currently have our geyser on a timer, so it only runs in daylight hours. Overnight our SOC hardly ever goes below 50%, including running the dishwasher almost every night and often a load of laundry gets done overnight as well. (For now, we switch back to Eskom if we use the oven at night, but once I double up the batteries we shouldn’t need to do that anymore)

When it's 4 of us, we can reach the morning with 70% SOC. Constant usage hovers around 230-300w in summer overnight (lights, fridge etc). When my parents join, the geyser has to work more... I let it go on in the evening after the kids routine for an hour, and then a top up early morning 4am... so about 3-4kWh in geyser alone (this will change to a heat pump geyser later this year). Then because we have the battery capacity, things like dishwasher, washing machine, tumble dryer (heat pump tumble dryer) are an option in the evening to use because we have the capacity... we don't limit their use if they are needed. In winter we used to put laundry and dish washer on a timer for in the day after 10am, then use tumble dryer as we get home while the sun was still up. In summer we don't need to do this because of all the extra capacity. In winter we have a small heater that we run in one of the kids rooms.

The extra battery will get us to the point where even in winter we don't even think about power usage in any scenario.

 

[Zellephant]

When it's 4 of us, we can reach the morning with 70% SOC. Constant usage hovers around 230-300w in summer overnight (lights, fridge etc). When my parents join, the geyser has to work more... I let it go on in the evening after the kids routine for an hour, and then a top up early morning 4am... so about 3-4kWh in geyser alone (this will change to a heat pump geyser later this year). Then because we have the battery capacity, things like dishwasher, washing machine, tumble dryer (heat pump tumble dryer) are an option in the evening to use because we have the capacity... we don't limit their use if they are needed. In winter we used to put laundry and dish washer on a timer for in the day after 10am, then use tumble dryer as we get home while the sun was still up. In summer we don't need to do this because of all the extra capacity. In winter we have a small heater that we run in one of the kids rooms.

The extra battery will get us to the point where even in winter we don't even think about power usage in any scenario.

Okay cool, yes makes sense using the capacity if you have it. Would also like to get there soon where we don’t have to think about how much power we use. Just need to wait for another bonus or the next tax return period to get us there.

 

[Snyper564]

Has MyBB gone from taking money from Monochoice to scare people into sticking with DSTV to now taking money from EksDom to scare people into sticking with them and not cutting their grid ties?

These prices being quoted seem a bit outrageous…. And would also like to see their per component cost breakdown.

I have just put in an off grid system designed to provide 15kwh/h per day (450kw/h p month). And we are planning to go fully off grid soon, if Eskom gets their way with regards to tarriff increases. If that happens, we will add an extra battery, but nothing more. So far my system of 6x550w panels, 5kw/h battery, 8KW invertor, installed cost me R42k, basically half of the quoted price for a similar system in this article.

I also can’t see why you need to go 5x on the batteries and 3x on the panels in order to complete cut grid ties? We are planning on adding an extra battery in a few months when budget allows, and that should have us covered - even in the Western Cape with long spells of rainy weather in winter.

Will also just run the generator to recharge the batteries if the need arises. Even from completely flat, a 5Kva gennie will recharge the batteries in full in about 3 hours, costing a few litres of petrol.

that price for those components def not mainstream items, the 8kw deye is R25k alone.... that leaves R17k for battery panels and install. I would be worried about quality tbh that battery is also about R15k.... what on earth did you install?

 

[Lupus]

Was going to say this.
Even people I know who have a generator have mostly stopped using it due to the pain of maintenance, noise etc.

As for the stated +-R100K in the article... that sounds about right, my small system (current generation between 200-300kWh per month) would have to double in size AND I'd need to sort out water heating which is currently being done with "unused power" from my solar system, obviously inefficient.

Was going to wait but Citipower in JHB is crumbling so apart from the cost increases there's that.

I've still used my generator, sure not a lot but 4 times last year.
Twice in April and twice in Dec.

 

[RaptorSA]

I've still used my generator, sure not a lot but 4 times last year.
Twice in April and twice in Dec.

Yeah.
But batteries are shockingly cheap these days and I'm assuming the 2nd hand market for inverters must be super healthy by now... (and batteries too)

It's getting really hard to justify buying a generator, maintaining it and burning fuel in the thing, even if you live in an urban area where you can.

 

[Lupus]

Yeah.
But batteries are shockingly cheap these days and I'm assuming the 2nd hand market for inverters must be super healthy by now... (and batteries too)

It's getting really hard to justify buying a generator, maintaining it and burning fuel in the thing, even if you live in an urban area where you can.

View attachment 1786210

Usage of the generator is still cheaper than that. The 4 times used last year would've been about R120 and a service is R500, it's there as a backup for when it's too cloudy and city power isn't around to cover.