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Solar PV and Battery storage - who has it?

Discussion in 'The Pub' started by robsalvv, May 10, 2016.

  1. So I have Solar PV at home. When I installed the panels, I was told there'd be 10+years of a bonus feed in tarrif for all exported power. However only a few years later, the Vic Gov are dropping feed in tarrifs to 5c / kWh. That's a pittance.

    My credit union is offering cheap "green" loans, so I'm looking at tacking on battery storage to the Solar set up, so that for the most part I will be living off my own power.

    I still have to crunch the numbers to see whether its worth it financially... as an engineer, breaking out the spreadsheet isn't really a big ask. lol

    The Tesla power wall seems to be all the rage at the moment and getting all the media but it's not the only option.

    In the meantime, I'd be interested to hear if anyone else has a storage set up and their thoughts/learnings/rough costs/etc.
  2. I haven't, but have looked at these myself. I am interested in any replies.
  3. I'd be interested to hear about battery options. We don't have solar because the feed in tariffs dropped so much I though "meh, wtf" and haven't bothered. But a storage system would be good, so will watch this thread develop....
  4. I have a good mate who lives in the Hunter Valley and I know he's got some pretty serious batteries, as well as solar arrays. I'll ask him for some info......
    • Like Like x 1
  5. The redflow one is a much better deal than the tesla. Better lifetime, more storage. Plus Simon Hackett is pure win.
    Battery system 10kWh approx 10 grand, total cost installed with inverter charger around 18 grand. Easily expandable thereafter. Note that's 10kWHr useable.

    Redflow's home batteries to start shipping in June
    • Agree Agree x 1
  6. If you have an active power consuming household during the day, Solar PV still has some serious advantages. With a decent system you will be seriously backing out consumption from the grid and that means pure savings. A dollar saved is a dollar earned. If you don't have an active home, then solar PV is hardly worth it.

    Thanks for the hot tip.
  7. I have two Solar setups, One on my Yacht and one on my RV,
    The panels are 14 years old and were used full time on the yacht in Fiji by the PO, On the hook, so no grid power at all,
    He ran a Architectural business off the Boat, He did have a generator but sold it as the solar and wind was putting out enough power,
    He had two Acid Batterys, 400 Amphours, 21 days at sea with every thing running 24/7, Nav Lights, Internal lights, Nav gear, electronics, Microwave, Self steering, GPS, Etc, I never even looked like running out of power,
    I have the 280 watt solar panels now on my RV, I have changed one battery to an AGM, the other one, I dont know how old it was died,
    Possibly 25 years old,
    AGM's are cheaper than a power wall, 200 amphour AGM's are around $500-00 each, No maintenance required like the lead acid ones, , you can stack them sideways, They do weigh 72 Kg's,
    You need a generator if you want to run A/C units off them, Diesel Generator with 240, 12 and 415 Volts are $1200-00 Brand new,
    For a house you would need at least four Batterys, That will give you at least a week with out sun,
    They do charge on overcast days,
    I will be buying 2 X 250 Watt panels for my Boat instead of the four I had, They take up less room and are very cheap now, 250 Watts is $210-00 in Melbourne,
    My 5000 Watt invertor was $500-00 delivered from China, Its the same company that makes Zantrax invertors for the American market,
    • Informative Informative x 1
  8. This ↑

    Whilst you will only get a couple of pennies for the export to the grid these days, every KW you produce yourself is saving you the full amount the power companies are charging for that KW. The trick is to get a system balanced to your needs/usage.

    As for batteries, even with the new players (Tesla and co) the price of battery systems is still not economical for most users. However, the good thing about the Tesla's IMHO is that their sales will hopefully force other manufacturers into the market, and that will drop the price.
  9. Have to agree with barry_mckibarry_mcki, IMHO battery technology isn't at an economical stage yet. If you are looking at something in even the near future make sure you get something that is very universal and batteries are easily replaced. Also consider siting, gas emissions etc. Battery life is not what you read in a warranty and there are many types all with their pro's and con's.

    There is also a bit of talk within the industry at the moment about some states considering additional rebates to help kickstart the sales for systems as well as using the systems to help reduce peak load (allowing network to take strain off infrastructure).

    Hybrid systems will become more affordable with volume, you just need to get one as the price drops just as PV did as efficiency improves in technology and manufacture.

    Choose wisely and do not get sucked in by the hype and clever advertising, payback period for batteries at present is almost infinite if you include all factors, only plus is the warm, green feeling you get.
  10. We are completely off the grid (wind and solar) and bought our batteries second hand from Telstra (4 x 100Ah AGM). They are just starting to run out of puff - 7 years down the track.
    Might be worth checking if Telstra are about to offload some batteries as a cheap alternative.
  11. 7 years out of 2nd hand batteries is pretty good, figures I've seen say 10 year from new if they have been looked after correctly with the discharge/charge cycles. Another source of batteries used to be from electric forklifts.
  12. Dunno if it's true, but I've seen it written more than once that it is now cheaper to use PV to heat water than a solar hot water system. Using a bog standard electric storage water heater saves on the additional plumbing required for a solar water heater (especially if you live in an area that freezes).
  13. With the cheap price of systems these days the cost of setting up a PV system to power the standard resistive original style hot water system is cheaper than plumbing up a whole new SHW system. The footprint to power the average hot water tank is somewhere between 6 to 8 panels, this would be a relatively large portion of the average (north facing) roof space, compared to the two panels used by SHW for the same size tank (because of the much better efficiencies heating the water directly from the sun). Also most hot water systems run on a cheaper tariff to that of the rest of the home power load.

    So the equation comes down to is there more savings having the roof space used for powering the more expensive household electrical load or the hot water ?

    One of the problems here in Tassie is the number of power outages. The design of our PV system (which is how most systems are set up) is it needs the grid 240v to be available to give the solar inverter a stable reference. If the mains goes down, even if there is full sun, the rooftop PV system is also off line. Our longest outage went for over a week, so even with a roof full of panels, it was our little 2.4kva generator that kept things going.
  14. Yeah, we have been pretty obsessive about looking after them. The wind generator spends a lot of time switched off to avoid over charging the batteries (and you get a lot of wind in NW Tas).

    What part of the island you in?
  15. We're right on the Tamar River at Hillwood, that's halfway between Launceston and George Town. Hope the recent fires didn't cause you too much trouble.
  16. Have to agree with Wokwon the Redflow Zinc Bromide flow batteries are an interesting technology. Higher install costs but better Cost of ownership/life. A number of technical advantages that would appeal to your engineering soul, no self discharge, higher efficiencies, discharge to zero capability. As you say though get your spreadsheets duelling. :)

    Redflow Energy Storage Solutions
    • Informative Informative x 1
  17. #17 robsalvv, May 11, 2016
    Last edited: May 11, 2016
    This point is not understood by most owners of solar PV systems. Power outages aren't so much an issue in metropolitan Melbourne so it's not really a drama for solar PV users.

    In addition to a decent PV array, commercially available battery systems sufficient to take a moderately efficient suburban house off the grid are in the order of $20k-ish with a 19.6kWh lead based battery banks. Plus a generator for back up so looking in the order of $21k at least.

    A decent 5kW PV system is about $10k, so that's in the order of $30k of commercially available system dollars to get off the grid and power a home. That amount of money buys A LOT of power bills.

    I'm not interested in going off the grid, but I'd like to back out the evening's peak priced power consumption and overnight off peak consumption if I can. That would essentially reduce my power bill to the daily connection charge which amounts to $400ish / yr currently. I can work out from there whether this has a decent DCF compared to the soon to be status quo of pumping out solar generation at 5c / kWh

    So far, quotes for Tesla powerwall based systems have varied between $10k - $15k installed. Lead battery hybrid based systems in the $11k - $21k depending on size. This isn't looking like a cheap project. I'm yet to hear from reflow... but am interested. If their 10kWh to zero % battery technology isn't too pricey to install, that could tip the balance as I'm pretty certain I'm not using 10kWh of an evening, so it would most likely back out all grid consumption when the sun isn't shining.

    Best I confirm my average evening and overnight consumption - been a while since I checked.
  18. #18 cjvfr, May 11, 2016
    Last edited: May 11, 2016
    If you have a smart meter, which you should by now you can get a Zigbee dongle and pair to your meter. That allows you to log your usage in real time. If you don't want to go that far most electricity providers have a web portal you can get logs and graphs of your usage albeit a day or so behind.

    Added Later:

    There is also the small scale energy arbitrage market that is starting to open. In this case your partner company contracts to but power back from you at a high rate and they will use all their customer base to act as a method of supplying short term Grid support. Because this type of power in the open market is the highest cost they can afford to pay you a high return.
  19. If your up this way Rob, Drop in and I will show you my RV system, Its exactly the same as a house system but on a smaller scale,
    If I plug it into the grid, I run both my A/C units off it,
    I took the 6.7 KVA generator out of it as I didnt need it, Im not keen on A/C,
    • Informative Informative x 1
  20. Finally getting around to crunching numbers...

    Found a lead based high capacitance battery system allowing 13.6kWh useable power consumption (70% discharge), in the order of $16k. (Not as future proof as the lithium bromides from Redflow - but apparently cutting edge lead technology at present).

    In summer, that sized storage will well and truly back out all typical power consumption from 6pm - 9am [evening (meals/family time/TV/Computering), over night fridge/standby power and morning/breakfast] in my current household after any decent shiny day. So effectively free loading off the sun. I can bank on that for at least 5 months of the year.

    It's not going to do that during winter though.

    If the batteries can be charged over night using off peak power and they remain topped up from the solar panels over the little winter sunshine that there is, that should mean that the household morning and evening peak (family/cooking/heating) consumptions would be effectively covered by batteries charged from off peak power. Any additional household consumption will be at off peak rates as the batteries switch off depleted in the evening... That should amount to about a 50% $ saving compared to a typical winter... if I go all LED's it should help too.

    Sounds good right?! That overnight recharge is a big iff apparently. It would be an essential feature to help the economics though, to get anywhere near a 10% return on the capital in the form of $savings, i.e., can it back out $1600 of consumption?? Money saved is money earned.

    The impact of inexorably rising power prices should make the economics look better too...

    Will have to break out the spreadsheet...
    • Like Like x 1