My energy cost reduction plan, comments ?

[Lester]

Backstory.

We have been with AGL for approx 40 years, now 38 years at current home.

Since my quarterly AGL electricity bills of the usual $650 - $700 (occasionally near $1000) were subject to the recent ~45% increase, and due to soar to perhaps every bill $1000 +, we decided to go solar.

We also had a new colourbond iron roof fitted to facilitate this, and fix the 38 year old tiles before making the further investment.

The new roof and gutters, plus solar have really been quite a high investment, perhaps a part of my reasoning was a little 'spite' to the massive increases in tariffs.

The cost for the above (so far !) is probably 40 quarters / 10 years !

I suppose the property value has increased a decent amount too though . . . anyway . . .

Went with 27 x Trina 415w panels (for 11.2kw), SolarEdge optimisers, 2 x SolarEdge inverters (one Energy Hub, one Genesis) as we have 3 phase, and to date (1 month in) it's all working great.

It has become quickly evident that users in SA can only really reduce their bills substantially with a battery for non daylight hours, due to the exorbitant different in max peak rates applying during these times, when solar doesn't wipe out the day use.

For some folks' interest, in SA we pay peak 50.171c inc gst, and feed in is 6c, so almost impossible to produce enough power to negate the 8.36 x difference.

From what I can find, there are really no better options that are simple from any competition here in SA.

Basically solar is best used to reduce all day usage, night if possible, you save 50c or so !!

Feed in is that low, it's best used to store and use yourself at night.

Perhaps there are other states in the same position with rates as we are in SA, but I've seen very much cheaper rates and better feed in paid for places (coastal Nth Qld) with only one supplier (not AGL), go figure.

So, besides removal of a couple of big gums in the backyard that will greatly block winter sun when it lowers come March / early April, we've quickly come to the decision to invest MORE $ with a battery.

Not sure what brand / type / size just yet, but in the coming 3 - 4 weeks we have several battery places calling to arrange a site visit and to quote.

A little more info, we are on Night Saver EV tariff, where along the best plan rates also have the override of just 8c per kwh between midnight and 0600 for all power into the home, so plan on the worst days to charge the battery up during that time, the rest of the year I anticipate we'll be fine to cover day use and charge the battery, before feed in commences.

So have any in a similar tariff structure also come to this realisation ?

And any other ideas to reach the goal or a near $0 bill ?

Comments on your solar / battery and how it's working for you ?

I'm hoping with a decent battery and the solar we have we can generally bring usage down to nil for all but worst of winter period.

And maybe, just maybe, the excess sweetener tariff feed in (as low as it is) will bring down or possibly eliminate the supply charge for several quarters a year.

[David_AGL]

Hi @Lester - nearly 40 years! That's amazing, thanks for sticking with us for so long.

And thanks for the insightful post about your solar set up and plans. We've got quite a few knowledgeable solar users here including @Caban , @John-T and @NeilC who I know has had great success in getting his bill as low as possible with solar. Interested to get their thoughts on your plans here.

No surprise that the shift to batteries is an increasingly strong trend, and I'd be interested to hear @thunter 's take as IIRC they were planning to make that move soon as well.

[Lester]

Cheers David.

In the past we've stuck with 'the devil we know' having changed telcos once with promises and bad cost experience, that was enough to steer us to keep with the best plans we could with the main players in each industry.

To be honest, I looked around pretty well when the recent 45% increase hit us, and we decided to go solar at last.

SA has lousy 'competition' though, all seem around the same rates for various plan types, with peak about 50c / kwh.

What gets me, my brother in Nth Qld, he's only got one supplier to his town / region, the usage charge is about 30% less, and his feed in on solar 110% more than we get here !!

And have read a few posts on here, mentions of some day use (WA) getting 8c/kwh ??

Comments gleaned regarding other states seem to be far less than SA too in some cases ?

It really is very disheartening to see where power coys are going with pricing.

People are coming under attack on their budgets from almost all facets of day to day necessities.

Anyway, the battery quotes and advice are filtering through, and we might not even need one, we seem to be in credit daily apart from some initial hiccups in settling in.

Though it would be handy to totally eliminate our power bill, and be sure to cover winter with far reduced solar, also in the event of power cuts / load shedding as and when they happen very rarely. 

[Caban]

@Lester 

I have posted this elsewhere, but will repeat here.

I was lining overseas for a few years and returned to NSW just as the 60c FiT was ending. If I had really rushed I could possibly have got it but I do not like making rushed decisions. I did decide to install a Solar System after looking at the options back then. A few friends did rush in and ended up getting systems which were not the best quality, just to get the big FiT. It did work out but they were looking to update a few years later.

Back then, more than the cost of power, I wanted to address the reliability of my supply. I did consider installing just a battery, charging it from Off Peak and not bothering with Solar.  Eventually I did get a Solar/Battery system installed in 2013. The Inverter was a Netherlands based system (NeDap) and I had a bank of Lead Acid Batteries. It was nice to be the only house in the street with power when everyone else was in darkness.

One day in 2017 I got a call at work that the Inverter was on fire and shooting sparks. I rushed home and disconnected it. The system was still under the 5 year warranty, but the local agents had closed. So i had to claim directly to the Netherlands. They requested a report on the damage and photo's, which I supplied.They agreed it was a write off but would not honour the claim as the inverter was installed outside the house, but sheltered from weather. The unit was IP65 rated but they said it needed to be installed inside to get warranty. If I had done that I would have lost my house due to the fire. The unit was installed by their agents where they suggested. Still too hard to pursue consumer rights internationally. Instead I claimed on my Home Insurance. Ended up with an Australian made Selectronics unit and some additional Panels. About a year later my Lead Acid batteries failed. It was probably due to them not being cycled during the breakdown and claim. They were then 7 years old and beyond their  5 year warranty. I was hoping for 10-12 years but they had paid for themselves (just).

Looking for new batteries I wanted something that was better with new technology. Most offerings were Lithium Ion. The other option was Nickel Iron. I did not like either option. The Nickel Iron are long lasting but they are quite high impedance, especially when cold. They can balk high current loads. The Lithium Iron are low impedance but there can be thermal runaway issues and their lifespan is not much better than the old Lead Acid (about 12 years) While they are great for transport as they are very energy dense that is not a vital spec for a static installation.

What I bought were a set of LTO (Lithium Titanate) which are not as energy dense, but are very stable without the thermal runaway risk and have a very long life expectancy. They were about the same price as Li-Ion at the time but I have a new for old warranty for 20 years and a life expectancy of 50+ years.

The system is working well and I rarely use any grid power. I have a spreadsheet to evaluate the best power package for my uses. The defining parameters are not the actual rates, but the FiT and the daily charge. At present I have gone from about $50 a quarter to getting a credit each quarter.

While most sales people will push the Li-Ion products assess them on their payback period and use of resources. If they payback the investment in 10 years and need to be replaced in 12 years it's not a great deal, unless you are the Musk Stick. Extend the lifespan and it makes better financial sense and uses less resources from the planet.

[Lester]

hello @Caban thanks for the reply.

"I did consider installing just a battery, charging it from Off Peak"

That's something many don't think about, and something we will do in winter and shoulder seasons, when solar efficiency will be well under our average now.

With the 6 early morning hours of 8c usage tariff, we could easily top off a battery at a very good rate, and could have done this even without solar. 

But, you have to consider how easy it is for suppliers to drop / or significantly change plans, reduce or even eliminate solar FITs as their whim, THEN a battery would be a lifeline to powerproof your home and bills.

The battery chemistry is interesting.

So are batteries installed to the grid available in such a wide range you can have quite the range to choose from ?

Do these batteries need to be approved for grid connection, and are all batteries like your original lead acid ok to fit ?

I take it they have quite low tech battery management abilities, or are there aftermarket modules that can be used ?

These would have to cater for splitting power generated as desired to home use, a battery, or charging an EV, and finally the grid.

I read that Tesla used a different chemistry in their original powerwall (nickel-manganese-cobalt), and then changed to lithium-ion where the cathodes are made from a compound of Lithium, Cobalt, Nickel and Manganese.

The powerwall 3 is using Lithium Manganese Cobalt in it's make up.

Most now are using lithium ferro phosphate, not sure how that is in general, perhaps a compromise is being made here with cost / efficiency, and consideration to other factors.

Have a bit longer to determine IF we need a battery.

It'd be handy, reasonably sure we'd never get a power bill again, even with something lower in capacity to the usual 10+kw sizes.

Priority now is get the HWS on a dumb timer for cheap heating 0000 - 0600, get 2 large gums trimmed way back to allow for decent winter and shoulder light (less leaves too !), get 2nd HWS on kitchen side of house to save long trip across roof space, hook up to same timer, then we might just about negate our bill to a point where a battery is simply not a good investment $ wise.

We have reduced a full quarter estimated usage pre solar of about $10 to $11 plus a day, to the last bill 50/50 quarter pre solar and solar of about $5.40 a day, and now for first 19 days of pure solar / grid, and even with son home for a good week using 30 - 50kw a night charging (cheaply), it's down to $1.97 a day so far.

This is with supply charge and gst.

Each day it's going down 5c to 10c avg with just me and the wife in the home.

So, while blackout protection would be nice to have too, recouping a battery install cost of up to just under $15k is starting to seem hard to justify at this point, especially if the few little system mods for HWS(s) can bring down usage that bit more.

Again though, if certain plans are dropped / changed, or FITs eliminated, a battery would virtually be a necessity to anyone with solar, otherwise you are giving away your often generous kwh over home needs for nothing, and not covering what's used at the more exorbitant peak rates outside daylight hours.

I can see that coming in the near future, as the grid simply doesn't need so much feed in from home / commercial solar during the day, as it gets taken up more and more.

Thanks again for the input @Caban I will come back for a read once we decide to look at the battery scenario again this year.

[Caban]

@Lester 

So are batteries installed to the grid available in such a wide range you can have quite the range to choose from ?

I am not sure what you are asking here. There is a variety of battery chemistry available. When I first fitted batteries the only affordable batteries were the, so called, Deep Discharge Lead Acid batteries. They really do not like being discharged below 60% of capacity. The other issue is that you cannot swap out one unit of a set. One dies they are all gone. At the time Li-Ion were available for small devices but for larger capacity installations they were prohibitively expensive. If I had paid the ransom at the time then they would be approaching end of life very soon.

Do these batteries need to be approved for grid connection, and are all batteries like your original lead acid ok to fit ?

I don't think any approval for the grid is needed, but they have to be compatible with the Inverter and Power Management System. This needs to be well isolated from the grid. That way your installation can remain operating when the grid is down. This is why when most houses with solar still have a power failure even though their panels are producing ample power. they have to shut down if they are not well enough isolated to ensure the system cannot feed power back into the grid and make the lines unsafe for anyone working on it or cause a fire.

I take it they have quite low tech battery management abilities, or are there aftermarket modules that can be used ?

The management system has to be Battery Capable. So If you add batteries you will also need to get a new Inverter and Power management system.

[Lester]

Ah, yes pretty much what I was asking, older systems and pure off grid can run on just about any battery tech, though of course there are many variations in benefits, and older batteries like deep cycle / AGM are not as good in performance in this era.

"I don't think any approval for the grid is needed, but they have to be compatible with the Inverter and Power Management System. This needs to be well isolated from the grid. That way your installation can remain operating when the grid is down. This is why when most houses with solar still have a power failure even though their panels are producing ample power. they have to shut down if they are not well enough isolated to ensure the system cannot feed power back into the grid and make the lines unsafe for anyone working on it or cause a fire."

Yes, what you are having there is more of an off grid system back in the day ?

Did that system export to the grid too ?

I guess these BMSs could work similarly as the integrated batteries available now for home solar / grid use.

. . . and it could be switched manually or automatically via a BMS to run the home essentials.

Now this is ALL incorporated into these very expensive modern home batteries.

Better ? I suppose it's all relative to the system involved, but I would have thought that now the network managers would only allow connections to approved home batteries like Tesla, BYD, Solar Edge, and so on.

While these can be used as stand alone batteries, they are more designed for home / grid integration and performance.

Will be interesting as we work through the seasons and see where we will end up with getting one or not.

[Caban]

@Lester 

My original system was an early Grid Connected Battery System. It ran like a UPS (Uninterrupted Power Supply) but there was a small delay in the case of a switch over.

The earlier Off-Grid systems were not approved for grid connection (AFAIK)

My controller is made by Selectronics. It does not cater for on demand supply. To get that option you need to buy the set ups they approve. Instead I selected the system which suited my needs the best.