I must admit when I see technology like the Tesla Powerwall it grabbed my attention as I'm sure it did others. A battery that could power a home, I'd like to see that.
However as I start checking the information I start to think perhaps this isn't the big advancement in battery technology I was hoping for. But before I explain, check out the size of the batter compared to the car. It's huge measuring 130 cm x 86 cm x 18 cm.
First let's look at price. The 10 kWh battery is $3,500 USD so if we factor in exchange rate, plus GST plus we generally pay more in Australia, I suspect it isn't going to be far short of $6,000, if it does reach Australia.
The Powerwall is guaranteed for 10 years but that does make me think, it's a lithium battery and lithium batteries have a certain number of recharge cycles. We all have notebooks with lithium batteries that reached end of life. This
article may be useful in helping to estimate the expected life of the battery based on the depth of discharge.
To make use of the battery you'll also need an inverter and the services of an electrician, both of which will add to the cost.
The bottom line however is make sure you work out if the payback is there for your particular application. It may be, perhaps don't assume it will be.
For me the best approach has been to reduce our energy usage. We now use around 5 kWh per day which is around $500 per year of electricity usage charges. We can't avoid the additional cost of the daily service to the home and I'd be fairly sure the Powerwall wouldn't remove this need for most people. I'd have to save this amount and more for the Powerwall to pay for itself, so for me it's most likely not a good buy. However, as I said, each person needs to work out the payback for their particular situation.
Kelvin Eldridge
www.JustLocal.com.au