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.

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