In his signature #humblebrag tone, Musk ticked off the Class 8 truck’s impressive capabilities: It can tow 80,000 pounds, the most allowed on US highways, for a range of 500 miles. It has aerodynamics better than a Bugatti Chiron, a unique central seating position, and comes standard with enhanced AutoPilot, meaning it should never jackknife. Also: it's guaranteed not to break down for one million miles; it has a shatterproof windshield; and it implements a kinetic-energy-recovery system (KERS) in such a way that it will never need brake pads. Plus, with a motor on each of the four rear wheels, it can rocket from 0-60 mph in five seconds flat—one-third the time of the average diesel semi. Even fully loaded, that number increases to a scant 20 seconds, or a full minute faster than its smog-belching contemporaries. When towing up a five-percent grade, the Tesla can reach speeds of 65 mph, which is 20 mph faster than a diesel.

Taken in aggregate, these features and numbers would greatly benefit a trucker’s route in both speed and cost savings. They are eye-popping metrics; almost unbelievable. Which is perhaps why some are having a hard time believing them.

More important than what Musk said during his November announcement was what he didn’t say. For instance, there was no mention at all about the battery pack that will power the Tesla Semi to these magical thresholds. There was no mention of total weight or cost, which are arguably the two most important variables for long-haul shippers.

In terms of charging these unknown batteries, Musk promised a 400-mile recharge in the course of about 30 minutes. Based on recent estimates in Bloomberg New Energy Finance, hitting those numbers would require a charging system ten times more powerful than Tesla’s own Superchargers—currently the fastest consumer charging network in the world. The cost building stations that could hit those figures would be profound, as would be the potential stress on the electrical system from multiple trucks charging simultaneously.

Bloomberg estimated that in order to fulfill Musk’s promises the truck would require a battery capacity between 600 and 1,000 kilowatt-hours. Assuming a down-the-middle number of 800 kWh, that would necessitate a battery of more than 10,000 pounds, with a likely price tag north of $100,000. Musk also claims the Semi will be 20 percent less expensive than a diesel truck per mile—but that is with customers only paying $0.07/kWh. Experts estimate that Tesla will have to pay, on average, a minimum of $0.40/kWh* for "green" electricity—meaning the company would have to heavily subsidize charging costs for fleets of trucks sucking down terawatts of electricity.

So, in order to hit Musk’s stated targets, Tesla will require batteries that don’t, as far as anyone knows, exist; charging capability faster than anything on the planet; and rates far below current market value.

“I don’t understand how that works,” electric vehicle analyst Salim Morsy told Bloomberg. “I really don’t.” Investor’s Business Daily dubbed Musk's claims “monuments of envelope pushing.”

“The biggest concern that I have is that this is a typical Elon Musk ‘shiny object’ announcement to prop up Tesla’s stock price and distract from all of the issues he is having with Model 3 production,” an engineer associated with the hydrogen industry, who asked to remain anonymous, told us, referencing recent production delays and Tesla's loss of over $1.3 billion year-to-date.

“I don’t mean to be negative; I do believe in battery technology and its merits, and I also believe that we will continue to see significant improvements in battery cost and performance during the coming decades. But as a scientist and engineer I have always found Elon Musk’s lack of scientific accuracy and ability to overstate and exaggerate truth, and get away with it, very annoying and disingenuous.”

Tesla did not respond to requests to clarify these apparent discrepancies for this article.

The Truth About EV Trucks

Musk is not alone in the world of heavy-duty battery-electric trucks. VW recently announced a $1.7 billion investment towards developing electric powertrains for trucks and buses. Daimler, the world’s largest truck maker, unveiled an all-electric heavy-duty concept dubbed the E-FUSO Vision ONE at the Tokyo Motor Show, in late October. Daimler’s Class 8 truck promises a significantly more modest 220-mile range, with a payload 1.8 tons less than its diesel counterpart, and utilizing a 300 kWh battery pack. On paper, these figures make the E-FUSO Vision ONE more plausible than the Tesla Semi.

Of course Musk, a man who has promised to colonize Mars and builds spaceships to commute to the International Space Station, has never been known for making anything less than bold announcements. But shorter-range BEV trucks do have a place in the transportation ecosystem. This is known as “last mile" and "short haul,” where deliveries are made inter-city, or within 100 miles. In such a capacity, the Tesla Semi could be greatly successful. The semi truck business is a $30-billion-per-year industry in the United States alone, so there’s plenty of money to go around. But the Semi’s utility in true long-haul applications remains questionable.

Project Portal, a Real-World Zero-Emission Semi

Toyota has logged more than 4,000 development miles in a zero-emission Class 8 truck pulling drayage-rated cargo. This proof-of-concept semi, dubbed Project Portal, boasts 670 horsepower, 1,325 lb-ft of torque, and a 200-mile range. Rather than being powered strictly by battery pack—in this case, a comparatively small, 12kWh unit—Project Portal also utilizes twin fuel cell stacks plumbed from the Toyota Mirai consumer vehicle

Project Portal has been moving goods around the Port of Los Angeles since April, and on October 23 expanded its routes to distribution warehouses and nearby rail yards. The idea is to collect data while the truck performs real-world drayage duties, its itineraries increasing as the study progresses.

Like the Tesla Semi, Project Portal also boasts impressive acceleration versus a traditional diesel truck: 8.9 seconds to travel 1/8th of a mile versus 14.6 seconds. Unlike the Tesla Semi, however, it’s already at work in the real world, even moving supplies and auto parts for Toyota throughout Southern California. Its numbers are verifiable.