TESLA's 7 kWh Powerwall battery is mainly for solar. It makes great economic sense & is being continued...
Only their 10 kWh 'backup' batteries have been discontinued.
The issue here is battery chemistry & cycles, and hence price per kWh delivered.
costs $3000 & is good for 5000 cycles so cost per kWh delivered ~ $3000/(5000x7kWh) ~ 8.6c / kWh
That is spectacularly good for solar applications - probably a game-changer for off-grid applications...
The other battery was intended for a different use - power back-up
used to cost $3500 & was only good for 500
cycles so cost per kWh delivered ~ $3500/(500x10kWh) ~ 70c / kWh
That's not so attractive against lead-acid storage & traditional back-up generators, so TESLA dropped it. No big deal.
http://arstechnica.com/business/2016/03 ... y-for-now/
Tesla won’t be making 10kWh Powerwalls—it’s 7kWh batteries only, for now
Demand for 5,000-cycle batteries leads Tesla to tweak its business model.
by Megan Geuss - Mar 24, 2016 2:20am NZDT
Tesla has decided that it won’t be making the 10kWh stationary storage batteries it unveiled last April, instead focusing exclusively on the 7kWh version.
The 10kWh version of Tesla’s Powerwall was made to be used as backup storage only—its nickel-cobalt chemistry limited the user to cycling the battery 500 times, so daily use was out of the question. The 7kWh battery, on the other hand, is made to integrate with solar panels, and due to its nickel-manganese chemistry, Tesla said it could be cycled 5,000 times.
After Tesla quietly removed the option for a 10kWh battery on its website, the company confirmed in an e-mail to Greentech Media that the larger version had been discontinued. "The Daily Powerwall supports daily use applications like solar self-consumption plus backup power applications, and can offer backup simply by modifying the way it is installed in a home," the e-mail read. "Due to the interest, we have decided to focus entirely on building and deploying the 7kWh Daily Powerwall at this time."
The $3,500 10kWh Powerwall was the flagship consumer-focused product when Tesla unveiled its stationary storage plans last year. In fact, the company seemed to think the $3,000 7kWh battery wouldn’t sell very well in most states in the US, especially where solar panel owners can sell their energy back to utilities. In an earnings call last year, Tesla CEO Elon Musk said "the daily cycling one, it is true, in the US they are more expensive than being on the grid.”
“This doesn't mean that people won't buy it [in the US],” Musk added at the time. "Some people want to go off-grid on principle.”
Still, the company said expected to sell daily cycling units primarily to customers in Australia and Germany, where the economics work out a bit better for people with solar panels.
It seems from Tesla’s statement that the company isn't giving up on storage-only customers; it’s just producing one type of battery instead of two and will modify the smaller battery for storage use-cases.
Tesla has already started shipping Powerwall units to pilot customers and early adopters in Australia. Musk has said that Tesla will announce a second version of the Powerwall sometime later this year. The UK's first Powerwall unit was installed in Wales last month.
Personal view is TESLA will be using almost all its batteries for its cars - as many as it can make - but these storage batteries are a compelling insurance policy if that turned out not to be the case.