Even still looking at the current rates I am still better off using and storing my solar myself then pushing it to the grid.
enova solar premium rates
peak - 39.6c/kwh
shoulder - 24.2c/kwh
off peak - 19.8c / kwh
daily supply charge - 109.8c a day
my current plan with origin (recently increased. I think I was paying 18c / kwh before the previous renewal) there is a better plan but I don't want direct debit. I could probably get a better deal but I can change at any time I want as the plan is not locked in.
daily supply charge of 76.58 cents a day
7c / kwh solar feed in.
The 5kv solar array, battery and the smart inverter help me use the solar electricity instead of feeding it in to the grid. This saves me so much money on electricity bills it isn't funny. Batteries are not that expensive any more and it is becoming more and more viable to use batteries then to use the grid.
Glad we are now aligned on off-peak.
My annual bill in CQ before going Expat in 2010 was $1100-1200 pa and included the ambulance levy. We had no solar anything and installed AC 1-2 years before. No pool, but being an acreage, all water was pumped from tanks to header tank. Retailer was Ergon Energy, the regional (govt) power supplier for Qld.
The AC didn't increase our power costs as we were on a take or pay contract from previous owner as part of installation deal. So often our bill was less than contracted minimum price so what the hell we got AC and then it and the ambulance levy was removed, the price was roughly the same.
I had plans to install solar water heating when the eater heater gave up the ghost, but it was less than 10 years old and on tank water, so likely still running and on off-peak cost around $20-30/Qtr in power. In CQ with tank water you don't use hot water for 4mth of the year. Most of the cost was keeping it hot, not use.
PV was also on the agenda, but price was too high then to justify and I'm not talking economic break even as I didn't care about that.
Today, going by a few guides, the power cost would now be around $1500pa. With solar PV which I would have definitely got by now as I want it, about half the power cost will be eliminated and mostly fed into the grid as wife and I both work, leaving a few hundred bucks a year in grid connection fees and evening usage. We would have had a pool by now so solar PV would certainly fund the pool pump usage. I'm not sure a battery would be justified.
My brother in law with his 6.6kW system near Brisbane also on a acreage is ready to pounce as soon as the battery option gives him break even in less than 8 years. So far it hasn't and using the same energy model this morning provided by a supplier it still doesn't but getting close. The data I've seen on his system is that his house PV system has an net energy deficit about 5 days a year. Summer, hot humid weather with heavy cloud (classic SEQ weather).
The problem (and it depends on local factors) is often the grid connection fees. If you are paying for the grid, you may as well use it and forget the battery (for now). But things are changing and I suspect its not far from equal and if you say it works for you then great but even the green /RE friendly websites still rarely support it on economic grounds.
Having said that, our plan is to return to Oz in 2022 and buy an acreage or small farm, no grid connection with a 10kW system. Grid connection I'd only consider when the regulation changes on selling power into the grid. If I'm selling power into the evening peak, I want part of the pie of the peak rates. The technology is there to do it, so do it. Likewise during the day, the feed in tariff should reflect the grid price of the half hour its fed into.
Hence back to the train, on the current service, forget the battery. Just charge the train or grid when the train is not there and come the end of the day, what charge the train is lacking, off-peak to 90-95%, the rest you can get in the early AM.