Tesla Semi: 500-Mile Range, Cheaper Than Diesel, Quick to Charge

HAWTHORNE, Calif. — The Tesla Semi launched Thursday night to a host of superlatives. It’s faster, safer, and cheaper to run than anyone expected. Most of all, it will run 500 miles on a single charge, according to Tesla. The battery might have as much as 1 megawatt-hour of energy, we believe. And with a newer, super-faster Tesla Megacharger system, a trucker can add 400 miles of range in 30 minutes. The Tesla Semi will go into production in 2019, Tesla claims. No price was cited, but Musk hammered on the point that no matter what a Tesla Semi costs to buy, it’ll clobber diesel trucks on cost per mile to operate.

The Tesla Semi was unveiled at a Hollywood-worthy bash in a private aviation facility next to SpaceX HQ outside Los Angeles. In a Steve Jobs-ian “one more thing” kind of move, CEO Elon Musk made a semi-surprise announcement: Tesla will bring back a new version of its first vehicle, the Tesla Roadster. It will be, of course, the world’s fastest car, Musk says, with a 0-60 time of less than 2 seconds.

The Tesla Semi cabin is tall enough for standing. The driver seat is in the center, with a jump seat behind and to the side.

Super-Curvy Design, Driver in the Middle

Tesla put the driver’s seat right in the middle of the cab, with big touch screens flanking the steering wheel. Together with integrated telematics, they provide navigation, blind spot monitoring, data logging, routing, scheduling, and remote monitoring, replacing third-party devices required in traditional 18-wheelers. Entry/exit stairs are larger and easier to navigate. There is a second jump-seat for a co-driver or passenger. Inside, the cab is tall enough for the driver to stand up and move around. The Tesla Semi prototype is not a sleeper cab design, but it’s likely to be added.

There will be surround cameras for object detection, autonomous driving, and for forward and backward views to help the center-mounted driver see both sides of the truck. Enhanced Autopilot for the Tesla Semi would include lane departure warning and lane keep assist, automatic emergency braking, adaptive cruise control, and event recording. In the future, Tesla Semis can travel in a convoy, where one or more follow the lead truck with a driver. If the convoy snugs up close, they’ll also get better economy.

Tesla projects range at 500 miles. Our rough calculations say it will need a 750-kWh battery, possibly 1,000-kWh — that is, 1 megawatt-hour.

Tesla Semi Has More Range Than Expected

Before the unveiling, analyst and media discussion centered on whether a Tesla-electrified Class 8 tractor — “tractor” is the tractor-trailer term for the thing up front with the engine and driver — would get 300, perhaps 400 miles of range because it’s hauling 80,000 pounds, versus the 4,500 to 5,500 pounds that a Model S or Model X weighs. So it was a shocker when Musk said the Tesla Semi would have a 500-mile range.

By coincidence, Tesla notes the vast majority of freight is moved no more than 250 miles, meaning that a driver can go out 250 miles, drop the load, and come back without having to recharge. (If that 500-mile projection is solid.) Tesla says:

The biggest immediate cost-advantage comes from savings in energy costs: Fully loaded, the Tesla Semi consumes less than two kilowatt-hours of energy per mile and is capable of 500 miles of range at GVW [gross vehicle weight, about 80,000 pounds] and highway speed, accommodating a wide range of shipping applications given that nearly 80 percent of freight in the U.S. is moved less than 250 miles. Coupled with the low and stable nature of electricity prices [Tesla says – ed.] – which average $ 0.12/kWh in the U.S. and can be significantly less for commercial and industrial users, falling to almost nothing when combined with local solar generation and storage – owners can expect to gain $ 200,000 or more in savings over a million miles based on fuel costs alone.

The Tesla Semi is also quick. Musk ran off these superlatives: The Tesla Semi will accelerate from 0-60 mph in five seconds, by itself, with no trailer. With the trailer and a full 80,000 pound load, it’s 20 seconds to hit 60 mph versus almost a minute for a diesel truck. It will climb a 5 percent grade (steeper than it sounds) at 65 mph versus 45 mph for a diesel truck. Overall, Tesla says, “The Semi is more responsive, covers more miles than a diesel truck in the same amount of time, and more safely integrates with passenger car traffic.”

Regenerative braking  restores 98 percent of kinetic (moving) energy to the battery pack and provides “basically infinite brake life.” The Tesla Semi with its swoopy cab and flat undercarriage has a 0.36 drag coefficient, less than the $ 3 million Bugatti Chiron. But note that a drag coefficient doesn’t take in account an object’s size, so the Tesla Semi’s total drag will be significantly more.

The Tesla Semi battery pack is mounted low for a superior center of gravity. We estimate it weighs 11,000-15,000 pounds, provides roughly 750 kWh to 1 megawatt-hour of energy.

Battery (of Unknown Capacity) Gives Low Center of Gravity

Here’s what we know about the battery system: It’s big, it’s heavy, and it’s mounted down low for an exceptionally low center of gravity. As for battery capacity, Tesla gave us a hint: Tesla says the Semi uses “less than 2 kilowatt-hours” of energy per mile. Based on vehicle battery packs in use now, we know lithium-ion battery packs of at least 50 kWh weigh about 15 pounds per 1 kilowatt-hour of stored energy. So if the Tesla Semi uses 1.5 kWh per mile and travels 500 miles, that means the battery is 750 kWh and weighs 11,250 pounds. If consumption is closer to 2.0 kWh per mile, the battery at is as much as 1,000 kWh — 1 megawatt-hour — and 15,000 pounds.

Maybe Tesla will find some economies of scale, but the weight of the Tesla Semi is going to include at least five tons of lithium-ion batteries. In comparison, a 6 mpg diesel tractor-trailer would use about 600 pounds of fuel on a 500-mile trip. Long-haul tractors carry enough fuel to go at least 1,000 miles, or two-plus days of driving, with 250-gallon fuel tanks (1,700 pounds).

By mounting the batteries low, the solid mass of the battery pack(s) help make the truck even more crush-proof in an accident.

For the Tesla Semi, there will be a new charging device called the Megacharger that should be more powerful than the current Superchargers. The Tesla Semi will have 5X to 10X the battery capacity of a Tesla automobile.

The centrally located driver’s seat is flanked by a pair of LCD screens from the Tesla Model 3.

Total Cost of Ownership Should Be Lower

For the truck owner, cost of ownership is paramount. Musk says diesel trucks will cost 20 percent more to operate, $ 1.51 per mile vs. $ 1.26 per mile for the Semi. (The IRS calculates a passenger car costs 54 cents per mile to operate.) Tesla didn’t break out the underlying math so we don’t know how much of the claimed advantage is because of low commercial electricity rates and/or solar that would have electricity costs “falling to almost nothing.”

Tesla also points out there a fewer moving parts: four Tesla Model 3-derived motors driving the tractor’s four rear wheel-sets but no engine, transmission, differential or diesel-exhaust after-treatment system to maintain.

Tesla says the battery pack is designed to support 1 million miles of charging cycles – 2,000 cycles if you charge every 500 miles, 5,000 cycles if you charge every 200 miles – and the drive motors are also designed to run 1 million miles.

As with the Model 3, fans of the Tesla Semi can place a deposit – $ 5,000 down – against a purchase price that Tesla didn’t announce and a delivery date said to be in 2019. There are about 4 million big Class 8 tractors on the market now, with a quarter-million new tractors sold each year. 98 percent are diesel and most of the rest run on compressed natural gas.

Tesla Semis with Autopilot could travel in a convoy, with a driver only in the first truck. If they run close together, wind resistance drops and the cost, Elon Musk says, might be around 85 cents per mile, competitive with train freight.

Reality Check: What Others Are Saying

Early feedback from analysts and commentators was: Nice idea, but an electric truck is probably best for local deliveries. Then range is no issue, and Tesla wins points for emitting zero emissions in major cities that have air pollution problems. The Port of Long Beach, California, for example, wants to phase out diesel trucks on site in favor of compressed natural gas trucks and eventually EVs.

The Diesel Technology Form quickly chimed in. Executive director Allen Schaeffer said in a statement:

Aspirations and predictions for new fuels and technologies are high, but must be evaluated in the context of reality. Diesel is the most energy efficient internal combustion engine. It has achieved dominance as the technology of choice in the trucking industry over many decades and challenges from many other fuel types. … diesel offers a unique combination of unmatched features: proven fuel efficiency, economical operation, power, reliability, durability, availability, easy access to fueling and service facilities, and now near-zero emissions performance.

“Diesel technology is not standing still …. From coupling with hybrid-electric technology and battery storage systems, to pushing thermal efficiency boundaries, to utilizing 100 percent non-petroleum bio-based diesel fuels, the new generation of clean diesel power is part of a sustainable future.

We all benefit from a more efficient freight system. Fuel and powertrain choices are one part of that. The greatest opportunity for efficiency gains, fuel savings, lower greenhouse gas emissions and cleaner air – now – is to get more truckers into the newest generation of more fuel efficient and near-zero emissions clean diesel technology, as rapidly as possible.

Trucking and stock market analysts say Musk is the most likely person to shift the trucking industry in the direction of electric vehicles. But the rollout couldn’t have come at a worse time for Tesla, with Model 3 production lagging, labor feuds in the factory, and financial concerns. There’s also no place to build the Tesla Semi, since the Fremont factory is pretty much at capacity.

Equally challenging, Tesla has to build out a new megacharger grid, each charger using several times as much electricity as a Supercharger, which delivers 145 kW split between two vehicles, with a maximum of 120 kW per car. Could each megacharger want 500 kW to share among two trucks?

Anton Wahlman, an analyst with Seeking Alpha (who is shorting Tesla stock), wrote, “If you are going to charge such a truck to 80 percent in 30 minutes, God help the electricity grid. It will be like plugging in a minor city to the grid at that particular interstate rest-stop. Can you spell brownouts? — no, make that blackouts.” Wahlman also said prospective buyers want to know in advance about Tesla Semi durability so, between no clear factory location and the need to test, 2021 is more likely as a delivery date than 2019.

Tesla is not alone in the electric truck space. Others involved with lower-profiles, include Daimler and Volkswagen, diesel engine maker Cummins, and a Einride of Sweden prototyping a driverless electric truck.

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