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Question of the Day: How do you normally pay for purchases in stores?
Solar cost per kWh
- Thread starter AchmatK
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AchmatK
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Speedster
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Yeah. One month in and I'm on R139.66. Hoping to be under R2.50 by end of year 5.
Mike Hoxbig
Honorary Master
After 5 months I'm down to R61.80...
richjdavies
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You guys are so weird... Funny but weird
... I think you'll make some people think solar is really pricey!
I'm going to start saying how much my house cost per night slept in, or car per mile driven or bed per minute slept in.
It's all a bit silly isn't it? The panels and everything are worth something after (edit: after the period you're counting the kWh over!!), not zero like you're implying. The only true way to understand the cost is long term production over the life of the system, taking away any scrap value at end of life... I.e. it would be fair to looking at your depreciation over the kWh produced so far...
... I think you'll make some people think solar is really pricey!
I'm going to start saying how much my house cost per night slept in, or car per mile driven or bed per minute slept in.
It's all a bit silly isn't it? The panels and everything are worth something after (edit: after the period you're counting the kWh over!!), not zero like you're implying. The only true way to understand the cost is long term production over the life of the system, taking away any scrap value at end of life... I.e. it would be fair to looking at your depreciation over the kWh produced so far...
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Speedster
Honorary Master
In comparing buying a car vs Uber I think R/km is a valid comparison. Yes, asset value at the end of period plays a role, but surely so do costs.
In solar the alternative is buying municipal power per kWh, so surely a calculated kWh cost is a valid metric.
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Lupus
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Don't forget not facing outages anymore
richjdavies
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If that's what they were doing yes... But your dividing the total cost of the whole system that lasts 20 years by the kWh produced so far in a month or two.
So new car R1m. Driven 10 km, so R100,000 per km. Schucks, should have stuck to Uber?
Speedster
Honorary Master
If you end after 10 miles, then yes. But if you follow the thread costs are coming down every month as we produce more kWh. Eventually, hopefully sooner rather than later, self production cost will be lower than having bought municipal power.
richjdavies
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Not quite right. You're ignoring cost of capital and assuming all that power would have been bought... E.g. when you have excess and "dump" into a geyser / waste power converting/inverting.
So it can be more complicated
Speedster
Honorary Master
No one said it is perfect, but it does give a good indication. Unless you perhaps have a better metric we should rather use?
Let's not derail the intention of the thread... context is key.
OP was simply asking where everyone is in their life cycle of cost per kwh. It was not intended to be an accurate forecast of what we think we can recover for bought hardware, factoring USD/ZAR long term trends for adding batteries in 4 years, continental drift moving CPT 1.3cm further south each year, reducing yield by an extra 0.0147% over the normal annual panel efficiency losses, etc. Nor was it a philosophical debate about the alternative and intangible benefits of solar.
Anyway, I'm sitting at R17.97 after 17 months of production. But funny enough, I'm actually cash-flow positive from month 1. Essentially, I took R160k out of my homeloan to pay for the system. The amount of money saved in CoJ bills is R150-R250 p.m. more than the additional cost of interest that I pay to service my homeloan as a result of the bigger loan value. So huge smiles over here
OP was simply asking where everyone is in their life cycle of cost per kwh. It was not intended to be an accurate forecast of what we think we can recover for bought hardware, factoring USD/ZAR long term trends for adding batteries in 4 years, continental drift moving CPT 1.3cm further south each year, reducing yield by an extra 0.0147% over the normal annual panel efficiency losses, etc. Nor was it a philosophical debate about the alternative and intangible benefits of solar.
Anyway, I'm sitting at R17.97 after 17 months of production. But funny enough, I'm actually cash-flow positive from month 1. Essentially, I took R160k out of my homeloan to pay for the system. The amount of money saved in CoJ bills is R150-R250 p.m. more than the additional cost of interest that I pay to service my homeloan as a result of the bigger loan value. So huge smiles over here
Mike Hoxbig
Honorary Master
Would expect your saving to be a bit more than that? I'm saving around R1,500 on a similar capital outlay...Anyway, I'm sitting at R17.97 after 17 months of production. But funny enough, I'm actually cash-flow positive from month 1. Essentially, I took R160k out of my homeloan to pay for the system. The amount of money saved in CoJ bills is R150-R250 p.m. more than the additional cost of interest that I pay to service my homeloan as a result of the bigger loan value. So huge smiles over here
SauRoNZA
Honorary Master
Let's not derail the intention of the thread... context is key.
OP was simply asking where everyone is in their life cycle of cost per kwh. It was not intended to be an accurate forecast of what we think we can recover for bought hardware, factoring USD/ZAR long term trends for adding batteries in 4 years, continental drift moving CPT 1.3cm further south each year, reducing yield by an extra 0.0147% over the normal annual panel efficiency losses, etc. Nor was it a philosophical debate about the alternative and intangible benefits of solar.
Anyway, I'm sitting at R17.97 after 17 months of production. But funny enough, I'm actually cash-flow positive from month 1. Essentially, I took R160k out of my homeloan to pay for the system. The amount of money saved in CoJ bills is R150-R250 p.m. more than the additional cost of interest that I pay to service my homeloan as a result of the bigger loan value. So huge smiles over here
Looking only at my two full winter months so far I’m R500 in the positive every month from pure generation of what I would have been paying Eskom without even compensating for price increases anyway.
Yes I funded it up front, but I’m also putting that money back into my home loan every month with the difference I’m not paying Eskom.
So my budget is unaffected, in fact it’s locked in place and I no longer have load shedding as a sideline benefit.
This is the thing that gets me. I literally couldn’t give two shits what my ROI is. I have power when Eskom has a wobble and I have power when city power has a wobble.
Good enough for me. I don’t need to get RNd value. I have comfort and convenience values maxed out.
Same goes for the gas geyser install I did a few weeks ago. I no longer need to hope for clear sky’s or to have grid power to have hot water. As long as my bottles have gas - I have hot water. Don’t care about ROI.
But hey if you do; cool. You do you. I think it’s a bit silly to work it out and focus on it in our environment.
TedLasso
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I wholeheartedly agree with your methodology and thinking.
I have also noticed that I am spending an inordinate amount of time checking/following up on things since I got my solar installed. While this is ok for my first month as I learn and optimise loads as best as I can, I need to think about my 'resource cost' and the ROI spent behind this. My time should be spent on other things. So my plan is that by Aug 13 this month (it will be 1 full month of installation) - i have everything in place and then the only time I will look at system is if loadshedding hits and I need to adapt system settings to ensure the battery is sufficiently charged to keep the house running during the outage periods.
But still a shoutout to all of you on this forum that have helped increase my knowledge and understanding. I can't thank you enough. If there is ever a MyBB get together, I owe you all a round of beers or poison of your choice!
Yeah.. good luck with that. I spent more time than I care to admit, tweaking and looking at my system each day. Maybe it's due to all the various automations that I have in place or whatever.
Even today, I still look at the system each day to see what it's doing; but I spend significantly less time looking at it. Like you, I wanted to get it to a place where I can just forget it is there and carry on with life.
But I learnt that with solar it is never that easy. It is just the nature of the beast to see how it is preforming and to always try optimise. Wait until summer hits, your setup will behave differently and you'll probably try more optimisations lol
Anyway, point is, don't care about ROI - just try get the most out of the system and you'll only need to look at one figure to see if it is working - your utility bill, each month.
Congrats btw on the install, welcome!
Koosvanwyk
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Sounds like you are describing your significant other after a few years