If you read this article the implication is the savings were made all because of the Tesla Powerwall. A massive 90% saving. However dig a little deeper and if I'm reading the information provided by the person through their own site and other news sites, a different story starts to appear.
Yes the person has made savings. Whilst I don't know how many kWh per day the $660 bill was for, the bill was for 91 days and a rough estimate would indicate around 24-25kWh per day. The person has now reduced their usage through knowledge to 13.7209kWh per day. That's roughly a 43% reduction.
Reducing electricity usage isn't a saving that can be attributed to the Tesla Powerwall. The same or better can be achieved using a $25 power meter device and reading the energy ratings on devices. Power companies now provide sites providing information down to the hour on your usage. Knowledge that doesn't need any outlay.
This is all very rough, but I think you get the picture. If we reduce the electricity usage by 43% (first removing the daily service charge) the equivalent bill for the same usage would be roughly $326 compared to the post Powerwall bill of $50.39. Yes an excellent saving, but not quite as much. That's a saving of roughly $92 per month, and if we assume usage is the same every month, a yearly saving of roughly $1,100.
The set-up cost for the person for their system was $15,990. The payback period is thus around 14.5 years.
The person also mentioned they could have put the money into their mortgage for an interest saving of $750, which people often forget is also tax free. Put the same money into the mortgage over 14.5 years and the benefit would be around $31,000 tax free.
The problem here is not unusual. People only think about reducing usage after they've made a large investment. I nearly did the same. Instead I worked on reducing my usage first. My normal electricity usage was around 13-14kWh per day. It's now 5-6kWh per day. No solar. No large outlay. With discounts, once you're using the level of electricity grid connected solar no longer makes financial sense.
If you have mortgage or other debt, it really may be worth considering paying down the debt before making purchases like this that have payback periods that are near or longer than the life expectancy of the equipment. With electricity usage, first reduce your usage as best you can and only then look at the payback on investing.
The article in the newspaper really made me interested again in the Tesla Powerwall, but once I go through the numbers and research further, what's being said simply doesn't add up. Good unbiased knowledge can only help you make better and more informed decisions.
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