CofCT feed in tariff appears to be R1.04/kWh. Depending on how one looks at it, it could be very good. ROI might take a while but it can be recovered.

But the cost of your meter

23 minutes ago, Chris_S said:

But the cost of your meter

Assuming the meter costs R10k four or five panels will pay for it in 32 months give or take.

18 hours ago, Mako said:

Assuming the meter costs R10k four or five panels will pay for it in 32 months give or take.

You would think the least the City could do is cover the cost of the meter. 

I suspect COCT feed-in customers will/could be slapped with a R160 monthly fee for the bi-directional meter. And it will increase yearly, so the ROI will need more time.:-(

Quote

 

 

18 hours ago, Mako said:

Assuming the meter costs R10k four or five panels will pay for it in 32 months give or take.

I don't think so, show those calculations please and also your assumptions... every time there's load shedding you won't be feeding in and thus no power sent/panels paid off and what 5 panels are you talking about 100W panels? how much do the panels, the mounting hardware and cabling and the larger inverter that you presumably need to be able to do this, add to the cost that needs to be paid off?

I can see why they actually don't want everyone to feed into the grid, unless everyone has his/her own transformer with some auto voltage adjust, still having unreliable power sources feeding into the grid causes all sorts of problems and headaches that may make it less than desirable...

19 hours ago, Chris_S said:

But the cost of your meter

They've said  that they are looking into reducing the cost of the meter. But you're right to raise the point. This is a big part of why I have no difference in feeding back, the cost of the meter (in COJ) puts me into a hole that I can't dig myself out of.
 

1 hour ago, Kalahari Meerkat said:

I don't think so, show those calculations please and also your assumptions... every time there's load shedding you won't be feeding in and thus no power sent/panels paid off and what 5 panels are you talking about 100W panels? how much do the panels, the mounting hardware and cabling and the larger inverter that you presumably need to be able to do this, add to the cost that needs to be paid off?

I can see why they actually don't want everyone to feed into the grid, unless everyone has his/her own transformer with some auto voltage adjust, still having unreliable power sources feeding into the grid causes all sorts of problems and headaches that may make it less than desirable...

5 x 500 = 2500.  2500 x 5 =12500 (call it ten) 10 x 1.04 x 30 = R312/month x 12 = R3744/year x 3 years = Paid. As a bonus your PV system will kick in earlier and shut down later. My comment was confined to the cost of the meter.....panels and hardware will take longer but the extra panels will be a benefit in general too. Additionally most established hybrid installs brag that their batteries are full by 10 or 11 in the morning so for them there is no additional expense. Depends how one looks at it.

 

Edited January 26, 20233 yr by Mako
Add info.

48 minutes ago, Mako said:

5 x 500 = 2500.  2500 x 5 =12500 (call it ten) 10 x 1.04 x 30 = R312/month x 12 = R3744/year x 3 years = Paid. As a bonus your PV system will kick in earlier and shut down later. My comment was confined to the cost of the meter.....panels and hardware will take longer but the extra panels will be a benefit in general too. Additionally most established hybrid installs brag that their batteries are full by 10 or 11 in the morning so for them there is no additional expense. Depends how one looks at it.

Maybe consider the limitation that that on an 80A circuit breaker you are limited to 4.6kW inverter capacity for exporting. Not sure how this will be handled, if they will allow you to exceed it. Anyway, 2.5kW will be half of the system dedicated to just paying for the meter, and the other half will probably just cover own consumption if you're lucky. Not much room for exporting any more.

 

 

47 minutes ago, Mako said:

5 x 500 = 2500.  2500 x 5 =12500 (call it ten) 10 x 1.04 x 30 = R312/month x 12 = R3744/year x 3 years = Paid

you're not quite clear here 5 what? times 500 what? is 2500what? yes, 5 times 500=2500 marbles, cents, grains of sand? but yes, 5 x 500=2500

agan, presumably the previous 2500 marbles x 5 = 12k5, I also agree, still talking marbles? bolts? nuts? fuses?

I guess eventually it seems you propose to put 10kWh per day back into the grid for your payback period, but like I already wrote previously, with loadshedding and all, I don't think that's all that likely... also, in case it is not common knowledge, which it doesn't seem to be, if you want to feed into the grid, the tension from your feed in side, needs to be higher than the grids, for it to work, so, you push up the tension to 245V, your neighbour comes in too, now we're talking 250V the 2 dudes across the road also want in, now we're at 260V, your inverter has decided it doesn't want to play at these Voltage levels and stops, so it drops slightly to 255V or maybe more neighbours with gear that are happy up to even 300V come in to play... either way, if there were no loadshedding, it could work, but not at any significant amount of feed in power, before the Voltage gets too high and maybe even some gear in your home lets out a sigh and a puff of magic smoke...

 

You know exactly what is described in those calculations........... I've read enough of your posts to know you're not stupid 😉

19 minutes ago, Kalahari Meerkat said:

also, in case it is not common knowledge, which it doesn't seem to be, if you want to feed into the grid, the tension from your feed in side, needs to be higher than the grids, for it to work, so, you push up the tension to 245V, your neighbour comes in too, now we're talking 250V the 2 dudes across the road also want in, now we're at 260V, your inverter has decided it doesn't want to play at these Voltage levels and stops, so it drops slightly to 255V or maybe more neighbours with gear that are happy up to even 300V come in to play

I suspect that the reason it is not common knowledge is that you just made it up.  Do you really believe that you feeding in a few kW will raise the "tension" in your area by 5V?  Seriously?

11 minutes ago, Mako said:

to know you're not stupid 😉

you may well be wrong there... either way, I assume 5 panels of 500W each? cost how much etc.

read the rest of my scriblles and let it sink in...

then think about this, you're presumably wanting to put in solar to avoid load shedding and be less reliant on the grid... so extra bonus, feed in to the grid... but... you have to consume at least as much from the grid as you're feeding in, afaik CoCT want you to be a net consumer, not producer, so if you're feeding in 10kW per day, then you would also have to buy 10kW from them for the same period, maybe not per day, certainly per billing period and I may be wrong here, I think they charge you more per kWh bought by you than the 104c/kWh produced and sold by you, never mind the monthly payment for the privilege for selling to them in the 1st place... like I originally wrote, do *all* the calculations including *all* the extra costs on your end and then you will likely come to the realisation that its not viable and thus not really worth doing, if you're altruistic and think enough of us suckers paying for the privilege of feeding in to the grid will prevent the current rolling blackout scenario, I'm pretty certain you are wrong...

I'll check but.......I don't think you need to be a net consumer any longer. Any reduction in your monthly bill goes toward your payback even if you're a net consumer. 

 

Battery full by 9 am and more than 4 kilowatts (there's more as that is low sun and an almost full battery) goes to sleep for 7 hours or so. That could have earned almost R30 for today. In summer it'll easily export R900 for the month and pay for a meter in two years. Lot's of installations like this idle away for hours and hours every day.

13 minutes ago, Calvin said:

I suspect that the reason it is not common knowledge is that you just made it up.  Do you really believe that you feeding in a few kW will raise the "tension" in your area by 5V?  Seriously?

I suspect you're not too bright or just not engaging your brain before doing like 1000 monkeys on the keyboard? See how this works, you make me out to be a liar without doing your home work or thinking a bit, maybe not 5V, but 10V or more, depending on how much your are trying to push into the grid.

Have you ever tried to charge one battery from another one where the one to be charged has a higher voltage than the one you're trying to charge with? If not, try  it and report the results here, please.

AC in this regard is like DC, the one with the highest tension wins the tug of war/push of electrons...

53 minutes ago, Mako said:

Lot's of installations like this idle away for hours and hours every day.

Not here... making Yoghurt, backing baking! bread, running the pump to irrigate the garden... all using the electrons that would have not been allowed to flow otherwise...

Edited January 26, 20233 yr by Kalahari Meerkat
WTF backing?

5 minutes ago, Kalahari Meerkat said:

AC in this regard is like DC, the one with the highest tension wins the tug of war/push of electrons...

Thanks for this explanation - I must ask my lecturers in Electrical Engineering at UCT why they did not use this wonderful analogy....

My issue is not with the fact that voltages will increase - it is the magnitude that is the issue.  That depends both on the current and the impedance of the system. The electrical grid generally has low impedance, which is why your neighbours' grid does not drop by 5V when you switch on a 5kW load.  By the same token, if you export 5kW it will not raise the grid voltage by 5V (maybe 5mV).

Perhaps you will see a 5V change if you are the only consumer at the end of a very long transmission line with high impedance. (Perhaps in the Kalahari... but then that was not the context of your post)

Another idea is to run crypto miners with the excess PV. I'm sure you'll earn more than the feedin tariff. 

Run extension to your neighbour and charge them😂

3 hours ago, Superfly said:

I note in the UK people are also moving to self-consumption instead, albeit they have/had tariff plans with reduced rates at night - they do have more EV's tho', so higher usage requirements but nevertheless - the feed-in scenario would only benefit the municipalities as it currently stands.

Self consumption still gets half the job done. For every house that generates and consumes 10kWh, the load on the grid is reduced by that amount. 

OK, better for the grid if our notional house generates 15kWh, consumes 10 and pumps 5 back into the grid. But self consumption is still a help.

3 hours ago, Superfly said:

 

- I wonder how much will get fed in during winter months anyway... I can't think how CoCT can further incentivise their scheme other than subsidise the meter with rate-payers money and cut out some admin (unlikely) to increase the feed-in tariff.

They are looking at ways to cut the price of the meter. I am generally cynical about municipalities and their talk about allowing us to sell back to them, but COCT are going further than others.

Realistically, if they can significantly reduce load during the day, then they have a better chance of recharging the Steenbras system  and being able to use that during peak hours. That's the key differentiator here. Joburg, for example, doesn't have any sizable storage that it can control, so they can't do as much with all that free PV power during the day.

Edited January 26, 20233 yr by Bobster.
spelllin

7 minutes ago, Calvin said:

The electrical grid generally has low impedance, which is why your neighbours' grid does not drop by 5V when you switch on a 5kW load.  By the same token, if you export 5kW it will not raise the grid voltage by 5V (maybe 5mV).

I can't say, maybe google around and see whether there is some way of calculating this out, but, I suspect you'd need to know the impedance of the system outside your door and I have no idea what this may be, but I can guarantee you, if you're the only one in the neighbourhood trying to export, then its probably not too much of an issue, but if half the houses sitting on the transformer you're connected to are trying to export, I see sparks, flames and smoke emanating around the neighbourhood in general or no-one being able to push out much more than 100W or so...

The problem is, as I see it, if you want to export and not be penalised, undertake to export 1kWh 24/7, in other words, export 1kW all the time for 24kW energy exported over the 24 hour period, now, of course, using batteries, this becomes an expensive affair, but all the intermittent power sources on the grid are a problem, the one trying to sell power intermittently does't care, but he has to, else the *real* power producer says, no worries, we make like VK5/South Australia and put in a *BIG* Lithium battery to smooth out all this nonsense and charge everyone an extra monthly surcharge and poof goes the dream of making money whilst feeding into the grid.

I have two mates, with whom I have discussed the feed in issue extensively, Rob from New Zealand and Ian from Australia and its not all sunshine and roses, sure the consumption curve isn't a constant either, but if half the neighbourhood on one transformer wants to feed in intermittently, the tension issues become huge, huge enough that you won't be able to feed in... and of course, you're likely to want to feed in, when demand is on the low end, so now what? *BIG* Battery?

I went digging for more info and did some maths when they announced it.

Quick summary of changes and unknowns for anyone interested:

• CoCT will pay R1.04/kWh
• Net-consumer rule is apparently being dropped
• They are busy testing a different prepaid meter, if it passes all the tests then it will reduce the cost from R12k+ to around R5k (near the end of the interview: https://omny.fm/shows/the-john-maytham-show/cash-for-power-cape-town-gets-treasury-exemption-t)

What's unknown:

• Is there still a monthly fee to be allowed to feed in?  i.e. the R160 mentioned in this thread (I found a R200/month mention in another thread).
• Is there still a limit on size of residential system to be allowed to export (i.e if I understand correctly, most residential houses are limited to 3.6kW of solar panels if they want to export?)

 

Doing some napkins maths, based on 2kW of spare solar power to export:

If the monthly fixed fee is dropped:  You can recover the cost of the prepaid meter in just over a year.
If the monthly fixed fee is not dropped: It'll take 3-5+ years just to recover the cost of the prepaid meter. 

With the fixed monthly fee, in order to recover the cost of the prepaid meter in under 2 years, one needs to reliably export 14+ kWh per day (year round - so approx. 5,000kWh per year).  If there's also a limit of 3.6kW of solar panels allowed in order to export, then that means you need to be exporting 70%+ of your solar production.

Feed in is done on a large scale elsewhere and it does work. Most want to feed in to reduce their monthly bill and that's it. Anyone that wants to make money from feed in will come up against a hard limit depending on their supply rating..........There's no easy way to make reasonable money by feeding in so I don't think anyone will go that route. From the City's point of view it's more about reducing load shedding stages and the massive boost that gives to the economy.

If I was a ruthless city engineer, I'd allow feedback and at a decent rate...........then in five years I'd point to the small print and cut the rate to very little and I'd have gotten everyone to install substantial solar with enabled feed back and enjoy the ride. The thought has crossed my mind that the feed in tariff may fall once everyone was on board. I think this has happened in other countries.

 

Very good read which ties in with the topic of feed in generation - Electricity and load shedding - JP Landman