Energy Needed To Charge One Tesla Semi Could Power 3200 Homes For One Hour Say Researchers


John Feddersen is the director of Aurora Energy Research, an international market intelligence and research agency. He told the Financial Times recently that the power needed to recharge one Tesla Semi in 30 minutes, as touted by Elon Musk at the introduction of the electric Class 8 truck on November 16, would power up to 3,200 typical UK homes for one hour. His calculations are based on hauling a fully loaded cargo trailer for 500 miles — the real-world range of the Tesla Semi according to Musk.

Tesla Semi via Tesla

There may be some debate about the calculations. Figures lie and liars figure, after all. Tesla claims its Semi will use under 2 kWh of energy for every mile traveled with a full load. But that’s in steady speed operation on level ground no doubt. Climbing hills and accelerating up to speed would require a little more juice no doubt, even if some of it is recaptured under deceleration and braking.

The editors of Norwegian news site TV2 have done their own calculations. The typical Norwegian home uses much more energy than one in the UK — 20,000 kWh per year versus 4,000 kWh — but even at that higher rate, the energy needed to recharge a Tesla Semi would power 700 Norwegian homes for one hour.

Where is Tesla going to get all that power and how is it going to keep the cost to no more than 7 cents per kilowatt-hour, as advertised? The company talked about using solar panels (presumably, from its SolarCity division) and Tesla Powerpacks at Megachargers, but it’s unclear where those will be available in initial years. We know that the Semi has an 8 pin connector, leading to speculation that the more powerful truck chargers will have about 4 times the power of the Superchargers Tesla uses to recharge its passenger cars, but that’s just ~500 kW, far less than a megawatt.

Certainly, a large storage battery or two of significant size will be required to zap the Semis with solar energy when they roll into a truck stop at the edge of the superslab. What the cost of those will be and how they will be covered is still somewhat of a mystery.

We are left to await further details about the charging systems that will keep Tesla’s electric trucks powered up and working. But one thing we know for sure is — these are some powerful beasts.

Hat Tip: Leif Hansen

Update: This article has been updated to correct some mistakes and clarify the work of Feddersen.

About the Author

Closely following the transition from internal combustion to electricity. Whether it’s cars, trucks, ships, or airplanes, sustainability is the key. Please follow me on Google + and Twitter.

  • BigWu

    Firstly, 2 kWh per mile is about 16 mpg which is spectacular for a tractor trailer (they typically clock in a 6 mpg).

    Secondly, the Megacharger is simply a scaling up of the existing Supercharger. Tesla has stated that they’ll charge 400 miles of range in 30 minutes. That implies 1.6 MW of power (800 miles of charge per hour times 2 kW per mile).

    Superchargers currently pump a max of 145 kW so the Megacharger is a 10x scaling. That may sound like a lot, but it’s only 1.6% of the output of the newly live Tesla power system installed in Australia. IOW, it’s well within their proven capabilities.

    • Tadeusz Piskozub

      Trains in Europe routinely draw a continuous 4-10MW and nobody seems to have a problem with that.

      My take is that the problem with charging is inflated – Musk already said a few years ago that the chargers are modular and can be easily scaled up.

  • Joseph Brown

    It seems pretty likely that Tesla MegaChargers will have several PowerPacks on site. The electricity to charge the trucks will be drawn from these batteries — very likely as DC.

    In the beginning, it is easy to envision the PowerPacks charging (at very inexpensive commercial and off-peak rates) overnight, and discharging into trucks throughout the day. Solar seems like it will start as a supplement to this.

  • WebUserAtLarge

    How much coal/oil would it take to power 3200 Homes For One Hour?

    • Tadeusz Piskozub

      Around 400-500kg of coal and roughly the same number in liters of gasoline/diesel. Not much, but that’s 1t and 1,5t of CO2 for coal and oil respectively.

  • kvleeuwen

    Big numbers are big. The Tesla Semi is still three times more efficient than any ICE truck.
    Behind the huge grille of a semi is the radiator that dissipates most of that efficiency difference. That waste heat alone could heat quite a few homes…

  • Matjaž Ciglar

    Is there a problem with it? Electric load is declining across a board, so utilities will be happy to sell more juice. Beside this is cheaper to beef up interconnections than roads. Not to mentioned about 70% savings on energy compared to gasoline and on top of that, cleaner air and less noise pollutions are free gains.

  • Eco Logical

    Solar and Power Packs … Elon said it in his presentation!