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
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
I found this article quite interesting as it picked up a point I didn't realise. The 10 kWh unit is for backup and have a limit of 50 charging cycles per year so one per week. That's a major limitation that needs to be factored into any decisions.
ReplyDeleteThe 7.5 kWh unit does not appear to have this limitation, however keep in mind it will only have around the same number of recharge cycles which is given as 500. Based on other articles I've read that's a good figure to use as a guide.
http://www.theregister.co.uk/2015/05/07/bloomberg_tesla_powerwall_more_wall_than_power/
A couple interesting point which came out of the article are:
ReplyDeleteIt appears the price may be a wholesale price. The price installers pay to purchase the units from Tesla. That may mean there's a near to factor in a higher purchase price and thus the return on the investment based on a higher price may be required.
The second point is the articles states only the lower 7.5 kWh Powerwall can be considered since it doesn't have the 50 recharge cycles per year limitation. However there is no mention of any limitation for the 7.5 kWh Powerwall and that doesn't make sense. It is still a rechargeable lithium-ion battery and the same limitation of recharge cycles would apply. In order to provide a 10 year warranty there may be a different limiting approach. If you discharged and recharged the 7.5 kWh unit every day and there is a notional limit of 500 recharge cycles, that means only a few years of use. There's still information that has not been made clear.