My Solar Powered Home - 4 Years On

A Tribal Fi reader asked me to give an update on my experience of taking my home off-grid-ish

Only too happy to oblige

Wow, can't believe its 4 years since we installed solar. We originally had it fitted as a step toward our early retirement (which is also close to 4 years). I figured it was one less bill to worry about and it was quite a big bill. I'm also a bit of an eco-warrior on the quiet and would like to leave this planet as I found it or hopefully a little bit better.

If you live in South Africa you also have an incentive arguably more important than saving money and from a selfish point of view, more important than my desire to preserve the planet.....simply having electricity!

Having spent the first 37 years of my life in Britain, I honestly can't remember a day where there was no electricity unless it was an issue in our house that was more likely down to my questionable approach to wiring plugs or a faulty fuse.

In contrast, in the last 10 years of living in South Africa, I would estimate that probably 10% of that time had no grid power. Load-shedding is a word that most non-South Africans wouldn't really recognise but if you're a SAfrican or have spent any time here, it is a word that gets used very regularly, usually connected to an expletive:

For the love of Pete, We're f**king load-shedding again!

For f**k's sake, they've upped load-shedding to Stage 5!

The f**king President told us load-shedding was finished, so why are we sitting in the p***ing dark?

You get the idea.

For the uninitiated, a simple explanation of load-shedding is that your power is off at scheduled times throughout the day and night. At stage 1 or 2 you might only be off for 2 hours once a day. At stage 3/4 you might be off for 2 hours 3 times per day. At stage 5/6 you might be off for 4 hours a time for up to 12 hours per day. At stage 7/8 you are on rolling 4 hour blackouts with 2 hours of power in between.

I won't get into the why's and wherefores of how a country doesn't have enough electricity in 2024 but as you can imagine, the case for solar power is an easy one. I don't know the exact stat but I think in 2023 we had over 300 days of load-shedding.

The System

So that's the background and in January 2020 I took R300,000 / $20,000 / £15,000 of our life savings and had an inverter, battery and panels installed. For the tech geeks among you, the system is sized as follows:

• 20 x 330 w solar panels providing 6.6kw of output

• 1 x 10 kw inverter (3-Phase)

• 4 x 2.56 kwh Batteries providing usable capacity of 10.3 kwh

• 1 x Bi-directional meter to enable grid feed-in

Was it worth it?

Without a shadow of doubt. I have a small amount of monitoring to do to make sure we have enough battery for load-shedding but use the battery as much as possible to save money, but that's all done through an app and takes me a minute or two in the morning when I check the schedule or when the government change the level of severity which they now seem to do about 5 times a day. Other than that, I don't need to interact with it and we don't really notice load-shedding most of the time.

I say most of the time because my 10kw inverter is not big enough to power the entire house and would be maxed out. As such, non-essential high consumption items like the air conditioning, water boilers/geysers and my workshop (with lots of hungry power tools) don't function during load-shedding as they're not connected to the inverter.

How much have you saved?

Nothing yet, other than my sanity.

There are two ways to look at the number due to the massive yearly electricity price hikes over the last 4 years and the fact that the City of Cape Town have a two-tiered pricing model where the first 600kw per month is much cheaper than everything after it.

So if I simply look at the total consumption and deduct the solar portion, I've recouped R120,000 / $8,000 / £6,000 of my investment and had no load-shedding.

If I factor in, that without solar, I would use a large portion of my electricity at the higher tariff, it's more like R180,000 / $12,000 / £9,000.

If I take the average of the two, I'm right around 50% paid back and because of the ongoing price hikes, should break even around year 7 or in 3 years time.

Obviously, I would have invested the money had we not spent it on solar so if I factor that in as an opportunity cost, I reckon I'll break even in real terms by year 9.

Long term benefits?

So if we assume I'm paid back by year 9 and the solar panels, batteries and inverter make it to 20 years, I calculate i'll get around a 3x payback so somewhere in the region of R900,000 / $60,000 / £45,000

That is a big if....

By year 10, everything except the panels will be out of warranty so any major break down to the inverter or batteries will almost certainly result in a replacement as I'm pretty sure we don't have the skills here to repair that level of electronics.

The good news is that the cost of the system has approximately halved over the same 4 years so if that continues, it won't be a massive expense to replace any faulty components and renew the warranty without too much damage to the payback plan.

What would I do differently if I was doing it today?

This is an easy one, I would absolutely max out the amount of panels I have and cover every spare inch. Solar panels are the cheapest part of the system but they are also the "Fuel" that drives it. Most of us have some kind of home automation like WiFi plugs in our house. These make it super easy to put things on timers. e.g. turn the washing machine on only between 10am and 4pm when the sun is shining. If you have enough solar panels, you can power all of your power hungry appliances and charge your batteries at the same time. this means all the power in your batteries is available at night when there's no sun meaning you barely use any grid power. Also, more panels means your "window" of charging is longer because you generate more power earlier and later in the day when the sun is rising and setting.

Secondly, I would oversize my inverter and batteries so that every appliance can go on the inverter and the batteries are big enough to last 24 hours of normal electricity consumption. This would mean you're effectively off-grid and the grid supply is just there for backup charging of the batteries during bad weather etc. That was too expensive for me 4 years ago but now, my friend just had a system almost exactly double the size of mine for the same price I paid 4 years ago and now doesn't use any grid at all.

Finally, I wouldn't buy an "all in one" system. My batteries and inverter are all together which looks very nice but it means I'm tied to the same manufacturer if I want more batteries or if the inverter fails, the batteries are also a bit useless. That's something I didn't think about but it could be a real problem if that manufacturer goes out of business or discontinues my model. You should treat the Inverter, panels and batteries as separate purchases, not as a bundle then you can change and upgrade them in isolation and keep using the other components.

What about feeding into the grid?

Regardless of what spin the government or city put on it, feed in tariffs in South Africa are a rip-off and just shows how little the government actually cares about climate change or ending load shedding.

I paid right around R16,000 / $1,000 / £800 to have a bi-directional meter fitted, and it was a waste of money. I feed in to the grid more electricity than I take from it and still receive a bill from the city. They charge me approximately R3 per kwh I take out and pay me R1 per kwh I put in. That seems pretty rubbish but it's still 33% discount right?

Wrong!

Last month I took out 300 kwh and fed in 320 kwh. This how the bill went:

Electricity used: +R808

Electricity given back: -R295

Sub Total: +R513

Service Charge: +R220

Meter reading charge: +R5

Bill Amount: +R738

Amount "saved": R70

R70 saving per month divided by the R16,000 that it cost me for the meter means I'll break even in 19 years! And don't forget, I didn't use any electricity, I borrowed some and then paid it back with interest.

Ripoff!

So would you recommend installing solar?

Wholeheartedly, in fact if you haven't got solar and you could (if you had to) afford it, you're crazy not to.

I spent most of my career in the global energy industry and I can promise you that double digit annual increases on the cost of power are here to stay and as there's less customers to pay for it, it will only get worse.

Load-shedding will still be around in 5 years almost definitely and based on the track record of the SA government, probably still in 10 or even 20. Solar is already the cheapest form of power and the technology is still improving. If you can, you should. If you can't, at least save up for a small battery and a couple of panels that will keep the TV, Wifi and a light on during load-shedding or you and your family will have to spend a lot of time actually talking to each other and nobody wants that, haha!

I hope this is useful, if anyone has any specific questions, have at it in the comments, and I'll do my best to give you the info you need.

Until next time, keep living.