Tesla is pushing the launch of its electric Semi truck program to 2022 due to supply chain challenges and the limited availability of battery cells, the company said in its second-quarter earnings report Monday.

Tesla CEO Elon Musk has warned about battery supply constraints before and the effect it might have on the Tesla Semi, which was first unveiled as a prototype in November 2017. Back in January, Musk said the engineering work on the Tesla Semi had been completed and deliveries were expected to begin this year. He did add the caveat, at the time, that the availability of battery cells could limit the company’s ability to produce the Semi.

That warning was apparently warranted. From the shareholders’ letter posted today after the market closed:

We believe we remain on track to build our first Model Y vehicles in Berlin and Austin in 2021. The pace of the respective production ramps will be influenced by the successful introduction of many new product and manufacturing technologies, ongoing supply-chain-related challenges and regional permitting.

To better focus on these factories, and due to the limited availability of battery cells and global supply chain challenges, we have shifted the launch of the Semi truck program to 2022. We are also making progress on the industrialization of Cybertruck, which is currently planned for Austin production subsequent to Model Y.

While not mentioned on the call or in its earnings report, the delay follows the departure of Jerome Guillen, a critical executive at Tesla who was working on the development and eventual production of the Tesla Semi. Guillen’s resignation in June came just three months after he was moved from the president of automotive position, which included oversight of the Tesla Semi, to a role with less responsibility as head of heavy-duty trucking. Guillen had led Tesla’s entire automotive business from September 2018 until March 2021.

Meanwhile, Tesla’s Cybertruck, which is supposed to go into production in late 2021, looks like it might be pushed into next year as well. Musk didn’t answer questions, but comments from Musk as well as Tesla VP of engineering Lars Moravy during the earnings call suggest that it could shift to 2022.

Cybertruck is currently in its alpha stages of prototyping, with the basic engineering and architecture of the vehicle completed. While the Model Y takes priority, the company is moving into a beta phase of the Cybertruck later this year, Moravy said.

“We’ll be looking to ramp that in production in Texas after Model Y is up and going,” he added.

Musk leaned in on how difficult the Cybertruck would be, perhaps as a way to cushion expectations for its arrival in 2021.

“Cybertruck ramp will be difficult because it is such a new architecture,” Musk said. “It’s going to be a great product; it might be our best product ever, but it does have a lot of fundamentally new design ideas.”

He went on to make the point that he has used as other vehicles have gone from prototype to volume production: Manufacturing is hard.

“At the risk of being repetitive, it’s actually easy to make prototypes or a handful of small-volume production, but anything produced at a high volume, which is really what’s relevant here, is it’s going to move as fast as the slowest of the rough order of magnitude of 10,000 unique parts and processes.”

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