Tesla's energy storage business grew in the third quarter, but not by as much as Wall Street expected.
The quarter
Tesla deployed 13.7 GWh of energy storage products in Q3 2026, according to its Oct. 2 filing with the SEC. That is up 9.6% from 12.5 GWh a year earlier and up slightly from 13.5 GWh in Q2, Electrek calculated. It fell short of Tesla's quarterly record of 14.2 GWh, set in Q4 2025, and well below the 15.9 GWh analysts had expected.
A note on conflicting reports: some posts circulating this week described a "record 15.9 GWh" quarter. That figure matches the analysts' forecast, not Tesla's filing. Tesla's official number is 13.7 GWh.
Deployments are not revenue or profit. Energy has been one of Tesla's better-margin businesses, so investors will look for its gross profit when Q3 results come out on Oct. 21.
Megapacks at work: France's largest battery
One example of where those Megapacks end up: TagEnergy has inaugurated a 240 MW / 480 MWh battery at Cernay-lès-Reims in northeastern France, now the country's largest operating battery storage project, pv magazine reported. The site uses 140 Tesla Megapack units on just over 3 hectares and connects to grid operator RTE's 225 kV network.
The project was inaugurated on Oct. 1 after four months of operation. In that time it fed 70.5 GWh back into the grid and completed 145 full charge-discharge cycles over 125 days, according to the company. It is qualified to provide frequency containment reserve, automatic frequency restoration reserve and voltage regulation, the fast-acting services that keep a grid stable as more solar and wind come online. TagEnergy co-owns the site with Banque des Territoires, which holds 49%.
For homeowners: your car can now back up your Powerwall
On the residential side, software update 2026.33.5 added Vehicle-to-Home with Powerwall. When it is enabled (Charging > Powershare), a parked car plugged into a compatible Wall Connector can supplement a home's energy supply during an outage, extending backup time. It requires a Powerwall and only draws the car down to the discharge limit you set. Tesla's notes don't list which vehicles support it, so check the Powershare menu on your car.
What it means: Storage is still growing, but Q3 shows deployments can be lumpy quarter to quarter. Utility-scale projects like the French site show the demand Tesla is chasing, while Powershare gives owners with Powerwalls a reason to see the car as part of the home's backup system.
