Panasonic Tests Solar Battery Storage System In Australia

It may not be as pretty as the Powerwall, but it does the same job. It’s currently undergoing trials, so the full details are not yet available, but we crunched the numbers based on what we know so far.

While it all seems a little reactionary to Tesla's recent Powerwall announcement, the Panasonic system has been a few years in the making.

Panasonic is also partnered with Tesla in the building of the Gigafactory, so the two are not exactly in competition.

Interested in the Powerwall? Check out our number crunch and decide for yourself if it's cost effective.

Houses in Canberra will be part of the Panasonic test, where the 8 kWh batteries will be installed in homes that have suitable solar arrays. There isn't yet an actual price to buy the unit, or even confirmation it will be for sale in the same fashion as Powerwall.

The battery isn't as sleek as the Powerwall, but is about the same size. The cabinet measures 138 cm tall 97 cm wide and 28cm deep. It can provide up to 2 kW of power and charges at the same rate.

Panasonic estimate that the system could increase the self consumption rate of solar (instead of feeding it back into the grid) from 30% up to 60%.

So far Panasonic has teamed up with ActewAGL, Red Energy and Ergon Energy for testing.

The advantage of such a system is that it delivers the power at the perfect time -- right when everyone gets home from work, turns on the air-conditioning or heater and starts cooking dinner. Buffering these peak loads is in the best interest of the power companies, and gives a more robust and redundant grid with lower peak loads.

Even better, some of the potential infrastructure and power savings could be passed on to consumers in the form of cheaper electricity prices.

It hasn't been announced, but the systems could be sold individually, or installed by the power companies for a reduced price. It's pretty likely to include the latter, since Panasonic talks a lot about building smart solar energy grids.

Want to know more about Panasonic's technology? Check out the video below or skip on for our number crunch.

The Number Crunch

Since the partnership is aimed at homes with solar already installed, no mention was made about charging via off-peak power. It’s a safe bet that the system will be restricted to solar only, as this has the biggest benefit to the power companies. Of course, it’s also pretty handy for the end consumer.

We can’t crunch the numbers based on cost, so we took the reverse approach. What is the most you should pay for the system, assuming a 10 year payback time?

In Australia we have a huge range of electricity costs in different states and cities. A rough average puts it at around 30 cents a kWh. Mine personally is a little less, yours might be a little more.

We assumed a 10 year payback, as the battery unit is rated for a 10 year lifespan. It should keep running just fine for a long time after that, but may slightly reduce in capacity over time.

It’s pretty hard to know if electricity prices will go up or down in the future, so we have assumed they will stay the same. Technologies such as this (as well as solar) could actually reduce power prices.

If you aren't charging your battery, your solar power will be sold back to the grid. Unless you still have an older higher tariff, you will be lucky to get 8 cents a kWh.

Panasonic don’t give an efficiency, but an useful estimate (similar to the Powerwall) would be that we get 7.5 kWh out for every 8.5 kWh we put into the 8 kWh battery, after all losses (including in the inverter).

We have assumed that the battery is charged during the day by solar, then helps run your home during peak periods at night. We also figure that many people have a large solar array and can fully charge the battery even when it is cloudy.

Lost Solar Tariff Per Day -- $0.68 (8.5 kWh x 8 cents a kWh)

Saved Peak Power -- $2.25 (7.5 kWh x 30 cents a kWh)

Total Saved Per Day -- $1.57 (Saved power minus lost solar tariff)

Total Saved 10 Years -- $5730.5 ($1.57 x 365 x 10)

So if the total installed cost if less than $5730, then it will pay for itself in under 10 years. These numbers will vary of course depending on your power cost. Higher rates means it can cost more and break even, while if you pay less, then the unit also needs to be cheaper for the numbers to stack up.

Of course it may not be offered as a pay to install system. Power companies may simple give you a discount on your power to have the unit installed, which makes total sense from day one.

What do you think about home energy storage? What sort of payback time frame would you consider worthwhile? Tell us in the comments.



    My Melbourne home has a 4.15kW array in a great position. Over the year my daily average feed in is 10kWh so I should be able to take full advantage of the calculations as they appear above. But they are deceptive. From May to August (a third of the year) my total excess solar fed back to the grid drops below 6 kWh daily and averages around 4 kWh a day. That's not enough to charge the battery each day and will significantly blow out payback time frames. I would need a much bigger home (and roof space) to accommodate a solar array large enough to reach the charge targets above, and even then, they do not factor in low charge days (dark cloudy days) of which there are a good 15 each year where practically nothing goes back to the grid.
    With these corrections factored in, this unit would need to be installed for under $4000 inclusive of the required inverter. Like the offering from Tesla, I think Australians can expect to pay double that, making it a option for wealthy environmentalists only.

    Last edited 03/06/15 5:22 pm

      If your existing roof occupies the property area then you have a problem, but if its possible to increase roof area, then a patio roof over the pool and barbecue area are an option.

        No matter which way I do the maths, adding another $8000 to the setup price, in the form of another solar array, is not going to shorten the repayment time frames. At an estimated $8000 for the battery install it would likely be 20 years before we're in front and the battery will need replacing by then.

      mraedge with your 4.15Kw system you should be producing around 14kw on an average all year round day. If you feed in 10Kwh that means you must be using 4Kwh.
      I live on the outskirts of Melbourne and have a 5Kw system installed. It is only up for about 5 weeks now but i work on an average of 18Kwh production per day. So far i'm coming close and i will refine it as i go along as I am aware that we are going into longer days.
      I also saw an adapter on the market for not battery inverters so that you don't have to change your inverter so you don't incur the extra cost.
      Some of the assumptions made in the above article aren't quite right
      Feel free to contact me

        I'm not really sure what your point is, or if there is a question in there.

    It's a safe bet that the Aussie tax will make it unfeasible for us to own one but no doubt the power companies will rent them to you. Gotta keep the money flowing into their coffers.

    I have a similar size system to yours, 4.4Kwh, and average 15Kwh per day into the grid over the year. Lowest readings of 10.3 & 10.1 in May and June, but we are in Queensland and have not had an electric bill for the five years we've had the system and the system is fully paid for.
    I've been reading that to get the 20 year life cycle this style of battery must be fully discharged each night and charged again the next day. If this is true it will present it's own set of problems for just about any owner?

      Pieter - where are you reading this information? My research tells me that Lithium Ion batteries have no memory as such and therefore definitely don't need to be fully discharged and fully charged every day. The best lifespan is suppose to be with a DOD around 80/20 (80% discharge) and a 20/80 (80% recharge) they don't like to be fully charged for long periods or left discharged. Of course the device will no doubt have it's own builtin monitoring/charging system with algorithms to prolong their lifespan.

      I don't like what Panasonic is doing and incorporating the utility companies into the design of the storage product so that they can remotely access the batteries and tap into "our power". I hope Tesla stays well clear of this concept! What we need as consumers is a "standalone battery system with aggressive pricing". That is the only way we can disconnect from the grid and stick the daily supply charges up them! If Tesla's 10kWh batteries will be around $4K AUD each I will immediately install 2 of these, because combined with my 5kW PV system and 20kWh lithium storage my 4 bedroom family home in QLD becomes self-sufficient.

    This could be exciting! If these energy storage batteries work, we could really be making a real dent in our usage of non-sustainable sources of energy and the conversion to more green methods will only be a matter of time!

    Seriously!!! How about a frank disclosure that 2kw is totally dependent upon the power load of household, so..... argument or case for it is false!

    Next , direct quote "7.5 kWh out for every 8.5 kWh we put into the 8 kWh battery" 1stly you cant put 8.5 of anything into something that only holds 8.0, just a maths correction. But what LiFe battery on what planet delivers 7.5kWh from 8.5kWh and is cost effective for the common consumer? Wowsers you jurno's read 5 seconds of "blurb" and become industry experts and instead of helping the consumer you destroy their faith. So, there are a number of LiFe or Lithium Iron batteries around but they are false economy unless you live in a cold climate or use them in an air conditioned environment as they derate/turn off at around 30C. NOW LiFePo4 or Lithium Iron Phosphate batteries ARE the way to go, they will operate at upto 80C and do not explode like the others nor "break" if they get knocked. OH, did someone forget to mention the safety factor in their story?

    But seriously folks, do your research based on where you live, what works in Melbourne or Hobart will most likely fail if you take it to Brissy and beyond. I'd look at some of Aussie companies who have spent years researching and integrating technology that works in OZ!

    Just a passing comment from a sparky!

    It would be a more efficient setup if the number of green energy providers made available in the market is increased. Since both of them are not competitors, then there is no reason not to allow Panasonic to jump into the bandwagon and shortens the production process of the battery storage system.

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