Tesla semis and the laws of physics

23 11 2017


ANOTHER excellent and well researched article from Alice Friedemann. This pretty well confirms everything I told our mate Eclipse who believes in all this techno crap, because that’s all it is. I find it baffling how people get taken in by such rubbish.  Even if these trucks were going to be built, it would be a HUGE waste of Lithium batteries, because they are needed elsewhere, in things that we need to carry around for doing useful things…….

Loads of interesting links in the references at the bottom



Tesla Truck

Preface: Most people think that electric truck makers need to tell us the specs — the battery kWh, price, performance, and so on — before we can possibly know anything about their truck.

But that’s simply not true.  We know what lithium-ion batteries are capable of. And we know the kWh, size, and weight of the battery needed to move a truck of given weight a certain number of miles.  That makes it possible for scientists to work backwards and figure out how many kWh the battery would need to be to go 300 to 500 miles, what it would weigh, and the likely price for the battery needed for a truck at the maximum road limit of 80,000 pounds. [in Australia it’s 40 tonnes – our trucks have more wheels! We also have B doubles, some with 9 axles that can haul 64.5 tonnes https://www.nhvr.gov.au/files/201707-0577-common-heavy-freight-vehicles-combinations.pdf ]

S. Sripad and V. Viswanathan (2017) at Carnegie Mellon have done just that.  They published a paper in the peer-reviewed American Chemical Society Letters at the following link: Performance metrics required of next-generation batteries to make a practical electric semi truck.  Below is my review of their paper along with some additional cited observations of my own.

 — Alice Friedemann   www.energyskeptic.com  author of “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Derrick JensenPractical PreppingKunstlerCast 253KunstlerCast278Peak Prosperity , XX2 report

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Authors S. Sripad and V. Viswanathan felt compelled to write their paper because there are so many guesstimates of the likely cost and performance of an electric class 8 semi-truck in the media. But these hasty calculations don’t take into account critical factors like the specific energy density of the battery pack, vehicle weight, drag, rolling resistance, battery kwH to go a given distance, and weight of the batteries given current Li-ion battery technology.

The definition of class 8 trucks is their weight of 33,000 pounds or more.  We can assume electric class 8 trucks would have the same basic truck weight, because building them with light-weight aluminum or carbon fiber is too expensive. And unlike cars, where the average income of an electric car buyer is $148,158 (NRC 2015), and the amount of aluminum needed to light-weight the car is a small fraction of what a truck would require, the trucking industry is a cut throat business with razor thin profits.  Light-weighting them is out of the question.

The maximum weight of a truck allowed on the road is 80,000 pounds, so if the body weight of the truck is the minimum 33,000 pounds, then the maximum amount of cargo that can be carried is 47,000 pounds.

The authors found that a 900 mile range [to arrive at kms, just multiply by 1.6] is simply not possible with today’s batteries, because the weight of the battery pack required is 54,000 pounds plus 33,000 pounds truck weight, which is 87,000 pounds, well over the maximum road weight limit of 80,000 pounds. And this truck that can not haul cargo will set you back $500,000 to $650,000 dollars for the battery alone.

A 600 mile range isn’t commercial either. For starters, the battery pack would cost $320,000 to $420,000 dollars, and on top of that you’ll need add another $100,000 for the body of the truck. To move a truck 600 miles requires a 36,000 pound battery + 33,000 pound truck weight and the truck can only carry 11,000 pounds, which is 36,000 pounds less than a diesel truck can carry.

Musk claims the range of the truck can be as much as 500 miles.  Based on the figures in Table 1, that means the battery would cost $267,000 to $350,000 (also add on $100,000 for the truck body), and the battery will weigh 30,000 pounds + 33,000 pound truck weight and be able to carry only 17,000 pounds of cargo, which is 30,000 fewer pounds than a diesel truck.

Even if the range is on the low end of 300 miles, the battery will still be very heavy, 18,000 pounds + 33,000 pounds truck weight and and only be able to carry 29,000 pounds of cargo, which is 18,000 pounds less than a diesel truck.

The bottom line according to the authors, is that a 600 to 900 mile range truck will use most or all of their battery power to move the battery itself, not the cargo. The cost of the battery is $160,000 to $210,000 plus $100,000 for the truck body, so overall $260,000 to $310,000, which is $140,00 to $190,000 more than a new $120,000 diesel truck — considerably more than used diesel class 8 truck, which can cost as little as $3,000.

If anyone in the trucking industry is reading this, I’d like to know if a 300 mile range with just 18,000 pounds of cargo is acceptable.  I suspect the answer is no, because the Port of Los Angeles explored the concept of using an all-electric battery drayage (short-haul) truck to transfer freight between the port and warehouses, but rejected these trucks because the 350 kWh battery weighed 7,700 pounds and reduced cargo payload too much. Nor was the 12 hours or more to recharge the battery acceptable. Ultra-fast 30 min recharging was considered too risky since this might reduce battery lifespan, and bearing the cost of replacing these expensive batteries was out of the question (Calstart 2013).

Even if a way has been found to charge a truck in half an hour without reducing battery life, the amount of power needed to do that is huge, so new transmission, voltage lines, upgrading many substations with more powerful transformers, and new natural gas generating power plants will need to be constructed.  Across the nation that’s many billion dollars.  Who will pay for that?

It shouldn’t be surprising that a truck battery would weigh so much.  Car batteries simply don’t scale up — they make trucks too heavy.  The authors calculated that a 900 mile electric class 8 truck would require a battery pack 31 times the size and weight of a 100 kWh Tesla Model S car not only because of weight, but all the other factors mentioned above (aerodynamics, rolling resistance, etc).

If the Tesla Semi or any other truck maker’s prototype performs better than this, there are additional questions to ask.  For example, new diesel trucks today get 7 miles per gallon. But the U.S. Super Truck program has built trucks that get an amazing 12 mpg. But those trucks are not being made commercially.  I don’t know why, but it could be because this achievement was done by making the prototype truck with very light weight expensive materials like carbon fiber or aluminum, costly tires with less rolling resistance, and other expensive improvements that were too expensive to be commercial.

Performance can also be gamed – a diesel truck going downhill or on level ground, with less than the maximum cargo weight, going less than 45 miles per hour with an expert driver who seldom brakes, can probably get 12 mpg even though they’re not driving a Super Truck.

Who’s going to buy the Tesla Semi, Cummins EOS, Daimler E-FUSO, or BYD all-electric semi-trucks?

Most trucking companies are very small and can’t afford to buy expensive trucks: 97% of the 1.3 million trucking companies in the U.S. own 20 trucks or less, 91% have six or fewer. They simply aren’t going to buy an electric truck that costs roughly 2.5 times more than a diesel truck, carries half the weight, just 300 miles (diesel trucks can go 1,800 miles before refueling).

Nor will larger, wealthier trucking companies be willing to invest in electric trucks until the  government pays for and builds the necessary charging stations. This is highly unlikely given there’s no infrastructure plan (Jenkins 2017), nor likely the money to execute one, given the current reverse Robin Hood “tax reform” plan. With less money to spend on infrastructure, charging stations might not even be on the list.

The big companies that have bought (hybrid) electric class 4 to 6 trucks so far only did so because local, state, and federal subsidies made up the difference between the cost of a diesel and (hybrid) electric truck.  The same will likely be true of any company that makes class 8 long-haul trucks.

I constructed Table 1 to summarize the averages of figure 2 in this paper, which has the estimated ranges of required battery pack sizes, weights, cost, and payload capacities of a 300, 600, or 900 mile truck.

Range (miles) Battery kWh required Battery Pack Cost at $160-$210 per kWh Battery Weight kg / tons Max Payload
300 1,000 $160 – 210,000   8,200 /   9 8.5
600 2,000 $320 – 420,000 16,000 / 18 5.5
900 3,100 $500 – 650,000 24,500 / 27 0

Table 1. All electric truck data from figure 2 of Sripad (2017).   A diesel truck Max payload is 23.5 tons.  The max payload (cargo weight) is derived from the max truck road weight of 40 tons, minus battery weight, minus weight of the truck (17.5 tons).

As to whether the Tesla Semi will perform as well as Elon Musk says, it is not certain he will still be in business in 2019, because Musk and other electric car makers are competing for very few potential electric car buyers and with each other as well. There will never be enough electric car buyers because of the distribution of wealth. Sixty-nine percent of the United States population has less than $1,000 in savings (McCarthy 2016). At best the top 10% can afford an electric car, but many of them don’t want an electric car, don’t have a garage, prefer Lyft or mass transit, are saving to buy a house or survive the next financial crash.  And if states or the Trump administration end subsidies that will further dent sales.

Nor will there ever be completely automated cars or trucks, because unlike airplanes, where pilots have 8 minutes of grace before the crash to go back to manual controls, there is only a second for a car or truck driver to notice that an accident is about to occur and override the system.  The better the system is automated, the less likely the driver is to even be paying attention.  So the idea that the poor bottom 90% can order an automated electric car to their doorstep isn’t going to happen.  Nor can it happen with a driver – there is simply too little time to notice and react.

Just imagine if an automatic truck were hacked or malfunctioned, it would be like an attack missile with that much weight and momentum behind it.

Even if the Tesla semis are built in 2019, we won’t know until 2024 if charging in just half an hour, cold weather, and thousands of miles driven reduces driving range and battery life, if the battery can withstand the rough ride of roads, and be certain that lithium is still cheap and easily available.

The only thing going for the Tesla Semi is that electricity is cheap, for now.  But at some point finite natural gas will begin to decline and become very expensive, even potentially unaffordable for the bottom 90%.  As gas decline exponentially continues, all the solar and wind power in the world does no good because the electric grid requires natural gas to balance their intermittent power. There is no other kind of energy storage in sight.  Utility-scale batteries are far from commercial.  Although compressed air energy storage and pumped hydro storage dams are commercial, there are so few places to put these expensive alternatives that they can make little, if any meaningful contribution, ever.

Meanwhile, this hoopla may drive Musk’s stock up and distract from his lack of meeting the Model 3 goals, but investors have limited patience, and Musk has over $5 billion in debt to pay back.  It may be that Elon Musk is banking on government subsidies, like the $9 million State of California award to the BYD company for 27 electric trucks — $333,000 per truck (ARB 2016), and the Ports of Los Angeles and San Pedro who will subsidize a zero emission truck that can go at least 200 miles.


ARB. 2016. State to award $9 million for zero-emission trucks at two rail yards, one freight transfer yard in Southern California. California Air Resources Board.

Calstart. 2013. I-710 project zero-emission truck commercialization study. Calstart for Los Angeles County Metropolitan Transportation Authority. 4.7

Jenkins, A. 2017. Will anybody actually use Tesla’s electric semi truck? Fortune.

McCarthy, N. September 23, 2016. Survey: 69% Of Americans Have Less Than $1,000 In Savings. Forbes.

NRC. 2015. Overcoming barriers to deployment of plug-in electric vehicles. Washington, DC: National Academies Press.

Sripad, S.; Viswanathan, V. 2017. Performance metrics required of next-generation batteries to make a practical electric semi truck.  ACS Energy Letters 2: 1669-1673.

Vartabedian, M. 2017. Exclusive: Tesla’s long-haul electric truck aims for 200 to 300 miles on a charge. Reuters.

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