Elon Musk wants to transition the world onto renewable energy sources, but to do so, the world’s going to need a lot more energy storage. The CEO outlined a new battery production goal during Tesla’s second-quarter earnings call on Wednesday, hinting that the company could eventually produce multiple terawatt-hours of storage per year.

“In order to really make a fundamental shift in the world’s energy usage and really transform things to a sustainable energy future, if you’re not in the terawatt-hour range, it’s like, it’s a nice news story but it is not fundamentally changing the energy equation,” Musk told investors during the afternoon conference call.

It’s the sort of move that could spark a bigger jump to renewables. Batteries are vital for renewable energy because they ensure a steady stream of power throughout the day.

After all, when the sun isn’t shining and the wind isn’t blowing, solar and wind generators aren’t going to keep the lights on.

The Tesla-built Hornsdale battery in Australia, completed in November 2017, uses 129 megawatt-hours to store wind energy from nearby turbines and provide enough power for 30,000 homes. The Arsenal Football Club in London has a large enough battery to power the stadium for an entire 90-minute match, and GivePower is using batteries and solar to run a desalination plant 24 hours a day.

GivePower in Kiyunga. GivePower

In the wake of booming demand and a need for more capacity, battery production is soaring. Benchmark Minerals states that annual global production jumped from 19 gigawatt-hours in 2010 to 160 gigawatt-hours in 2019.

A staggering 68 plants could add a further 1.45 terawatt-hours to the mix by 2028.

There is still a long way to go: The IEA estimates that global electricity demand reached 23,000 terawatt-hours last year. Renewables accounted for around 24 percent of electricity in 2017, a figure that could reach 30 percent by 2023.

Of course, it’s not necessary to produce enough batteries to hold all of the world’s energy at once. Musk previously stated that 100 of his company’s Gigafactories could produce enough storage to transition the world onto sustainable energy. With Musk planning to send Tesla’s production skyrocketing, it could bring this goal within squinting distance.

The Tesla battery in South Australia. Tesla

Elon Musk’s Terawatt-Hour Plan: How It Currently Stacks Up

Tesla’s Gigafactory behemoth in the Nevada desert reached an annual production rate of 20 gigawatt-hours in August 2018. That in and of itself was an achievement, as it made the firm the largest producer of battery power in the world, and it meant that Tesla produces more capacity than all other automakers combined.

The Gigafactory now produces around 28 gigawatt-hours of battery capacity per year, Musk explained Wednesday. Including factories in Japan that further supplement the electric car lineup, the firm reaches between 30 to 35 gigawatt-hours.

Work on the Gigafactory is not complete. The company is aiming to reach an annual production rate of 150 gigawatt-hours of battery pack production per year. This would be a rate that Musk has previously described as “faster than bullets leaving a machine gun.”

Musk has stated that 100 such factories would be enough to transition the world onto sustainable energy.

But none of this is enough for Musk, who now wants to see the company reach “multiple terawatt-hours per year.”

More information about this goal could come soon. Musk suggested that a battery day, similar to the autonomous driving day, could offer “a comprehensive review of cell chemistry, module and pack, architecture, and a manufacturing plan that has a clear roadmap to a terawatt-hour per year.” That could arrive sometime between February and March 2020.

Tesla is planning to launch new vehicles next year, like the second-generation Roadster, Model Y SUV, and Semi truck.

But beyond these new vehicles, Tesla’s batteries could be used to help shift the markets to ditch dirty energy sources once and for all.