Want a Tesla Solar Roof? You may need to shell out for a Powerwall first

At Tesla, the company's stock price apparently isn't the only thing that's climbing lately.

Powerwall sales are also poised to rise, now that the automaker's big batteries are reportedly a prerequisite for Solar Roof installations.

The requirement is new as of September, and it comes as Tesla ramps up Powerwall production at its Nevada factory, per Electrek. Tesla did not respond to a request for comment on the report. The change seemingly reflects the inroads the firm has made on its hefty backlog of Powerwall orders. Tesla pinned the pileup on the global chip shortage last year.

Tesla markets its Powerwall batteries as a way for homeowners to rely less on the grid by storing solar energy "for use when the sun isn’t shining." Under Elon Musk, the company has repeatedly hiked the price of the battery system, which will now set you back at least $11,500. Tesla said it crossed its 200,000th Powerwall installation back in May, 2021.

Tesla's solar division recently recorded its best quarter in four years. However, its progress on this front appears to hinge on conventional solar panels sales. Tesla mysteriously put most new Solar Roof installations on ice earlier this year, but according to Electrek, the automaker is "restarting scheduling for the fourth quarter."

Requiring Powerwall batteries may help Tesla as it attempts to scale its own virtual power plant, which it piloted last year. Tesla described the program as a way for Powerwall owners to "dispatch" their batteries "when the grid is in critical need of additional power" — and boy oh boy does the grid need more renewable energy, particularly in California.