Tesla CEO Elon Musk kicks off deliveries of the company's heavy-duty truck, the Semi, at the Gigafactory in Sparks, Nevada.Tesla CEO Elon Musk kicks off deliveries of the company’s heavy-duty truck, the Semi, at the Gigafactory in Sparks, Nevada.

On Thursday, Musk spoke on stage at the company's factory in Nevada with Dan Priestly, the company's senior manager for semi truck engineering.

CNBC previously reported thatTesla started production of the Semi outside of Reno this year, where it mostly makes the battery cells, drive units, and battery packs that power its cars. Musk andTesla didn't say how many Semis they are delivering.

In December of last year, the Semi design was shown byTesla. There were issues with the battery cell supply and production was delayed.

Musk joked that he was sorry for the delay during the delivery kick-off event.

He gave the mic to the people from Frito Lay, which is the first customer to receive and use production Semi trucks.

The steering wheel and driver's seat are different between Class 8 and other heavy-duty trucks. Instead of using the left side in Europe, the Semi was designed with a steering wheel in the center of the cab and two screens on the driver's side.

We went inside Tesla's first Gigafactory

There were other electric heavy-duty trucks in the market.

Daimler and Volvo have both produced and delivered electric heavy-duty trucks to customers beforeTesla.

A new fast-charging system is one of the high-tech features not available elsewhere. The DC fast-charging system uses a water-based cooling system to make sure it is safe to deliver up to 1MW. The Semi can travel 500 miles on a single charge, according to the company.

Musk said that the new fast-charging tech will be installed at SuperCharging stations and used to power up Cybertrucks. The heavy pickup will be produced at the company's new factory.

Fans worried about his commitment to the electric vehicle business might be reassured by the event.

Musk has recently taken on new responsibilities as owner and CEO of the social media giant. He sold some of his stock to help finance the deal. He has been involved in a lot of conflicts since he took over.

Musk spoke about the company's environmental mission and vehicle tech.

Tesla's chief designer on Elon Musk, the Cybertruck and the future of auto design

There are 15 million passenger vehicles and 200,000 heavy duty trucks in the United States. The semi trucks represent a large portion of harmful vehicle emissions due to their size, weight, and the fact they are driven around the clock.

Those emissions can cause health problems for people who live near warehouses, ports, and other roads with lots of truck traffic.

Medium- and heavy-duty vehicles made up about six percent of the on-road fleet in the U.S. as of 2020. Ozone and particle-forming nitrogen oxide emissions are two of the pollutants generated by these vehicles.

Musk said that the Semi would help combat climate change and improve the health of people living near freeways.

Diesel trucks can be replaced by electric trucks.

At the Semi deliveries event, Musk and other executives did not talk about their systems. When Musk introduced the Semi, he talked about a future of self-driving trucks.

They didn't talk about how many trucks they plan to produce in the next year or how they will get the additional battery cells and raw materials to make them.

The shares of Musk's auto business did not move in after-hours trading.

You can watch the event here.