Tesla Announces Semi Event For September 24. Here's What Investors Need to Know

When Tesla (NASDAQ:TSLA) unveiled its all-electric Semi truck in 2017, analysts were largely bullish on potential demand.

"We believe this could set off competition for intelligent trucks in the industry," an analyst for Morgan Stanley predicted in 2017. "If the order books fill up quickly, any carrier that holds back placing its order could potentially have to wait several years to get its hands on a Tesla truck -- years during which its competitors could be running with up to a ~70% cost advantage."

Morgan Stanley stressed to investors that the Semi could be "the biggest catalyst in trucking in decades."

Other analysts were similarly optimistic. Analysts at Bernstein, for example, predicted Tesla would capture 3% of the semi market within five years. Piper Jaffray's research team believed that the Tesla Semi could revolutionize the company's revenue base. At the time, Tesla was generating just $11 billion in annual revenue. For comparison, Piper Jaffray estimated the market opportunity for Tesla's Semi truck to be more than $100 billion per year.

It has been nearly a decade since these predictions were made, and the results are clear: the Tesla Semi has been a major disappointment.

This time last year, only a few hundred Semis had been sold cumulatively. But things are starting to heat up. Einride AB just put in an order for 500 Semis, effectively tripling Tesla's lifetime sales for the truck.

Now, Tesla is planning a major Semi event on Sept. 24. According to reports, "The invite-only event will celebrate the opening of the new Semi factory and give attendees access to factory tours and ride-alongs in the updated Tesla Semi. The event comes several months after Tesla began building Semis on its new high-volume production line."

With production ready to scale alongside rising demand, is Tesla's Semi truck finally ready to make a meaningful impact to the company's bottom line? The answer is clearly yes, but there's one catch that investors should be wary of.

Tesla investors should understand this caveat to Semi sales growth

When the Tesla Semi was launched, big assumptions were made regarding the vehicle's ability to generate fuel savings and minimize ongoing operating costs. But higher upfront costs put a damper on demand.

Right now, the Tesla Semi is expected to cost around $350,000 when including the charger. A new diesel truck, meanwhile, runs closer to $165,000. Operating cost savings can be hard to predict. Diesel prices fluctuate, repair costs and lead times for the Semi aren't as forecastable as a conventional diesel truck, and local electricity prices vary widely. Plus, drivers simply aren't adapted to running an electric fleet.

Higher fuel prices may help spur demand, but many of those adoption barriers -- chief of which is operator inexperience driving and maintaining an electric vehicle -- remain. That's what makes the advent of autonomous trucking so attractive for the Semi's sales potential.

McKinsey & Co. sees autonomous trucking taking off in the U.S. by 2032 -- just five years away. Tesla has invested heavily in its self-driving technology. With an ability to mass produce Semis with long-term cost savings and minimal labor needs, I expect Tesla to benefit immensely long term. But the sales ramp won't just follow theoretical cost savings -- it will also hinge on how quickly autonomous driving technology is developed and approved by regulators.

So while Semi sales should ramp in the coming years, I'm not expecting a major inflection point until autonomous trucking becomes a reality.

Ryan Vanzo has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Tesla. The Motley Fool has a disclosure policy.