[dahfizz]

This sparked my curiosity...

Currently gasoline has about 50x more energy per unit weight than a tesla battery pack.

Battery energy densities have tripled in the past 10 years. Keeping on that pace, it would take over 30 years for batteries to be competitive with gas.

When you account for the astoundingly bad efficiency of ICE, though, the gap in usable energy decreases. This is why a tesla can go 300+ miles with a battery that can only store the same energy as 2.4 gallons of gas.

[Hypx_]

You're likely to hit a hard limit to what battery energy density can reach. The next step will be fuel cells which don't have the efficiency limits of traditional internal combustion.

[rsj_hn]

The Tesla can go 300 miles by making it light, aerodynamic, brakes that recharge the battery, not turning on the heater, etc. Yes, it's a significant engineering accomplishment, but in the heavy long haul world when analyzing break-even points what matters is range improvements due to an increasing energy/weight ratio, not range improvements due to reducing air resistance and inertia. This is because the form factors of the boxcar are basically set by shipping container needs and the weight is going to be determined by the load you are carrying. Munro is advocating for hydrogen powered trucks and planes as hydrogen has similar power/weight characteristics to gas -- electrification of these is going to be a challenge.

[outworlder]

> by making it light

If there's one thing that EVs are not, is "light". Model S ranges from 4,561 to 4,941 lbs. A model 3, 3,648 to 4,250 lbs. A Nissan Leaf - 3,538 to 3,946 lbs.

In comparison, a Honda Civic weights 2,771 to 3,012 lbs.

Regenerative breaking is nice but it's very dependent on the particular drive and terrain. Heaters are power hungry as there is very little waste heat that can be used (again, due to the high efficiency), unless they are heat pumps.

The main reason they can go so far with so little energy is the efficiency of electric motors.

> as hydrogen has similar power/weight characteristics to gas

No it doesn't! It has horrible energy density per volume, compared to any gas or liquid fuels. You can improve this by using high pressures (energy loss) or cryogenics (even more energy loss). But it's pretty bad to begin with. Turns out that the best way to store hydrogen is by adding some carbon atoms to it.

[rsj_hn]

> If there's one thing that EVs are not, is "light". sigh

Obviously we are not comparing about the weight of an EV compared to an apple or vehicle that doesn't require a battery. We are talking about extreme measures taken to make the car lighter so it can improve range. Replacing cheaper steel with more expensive aluminum, reducing even surface area of plastics, reducing wires. Truly amazing steps were taken to reduce weight.

> No it doesn't! It has horrible energy density per volume,

volume? Seriously? "The energy in 2.2 pounds (1 kilogram) of hydrogen gas is about the same as the energy in 1 gallon (6.2 pounds, 2.8 kilograms) of gasoline." https://afdc.energy.gov/fuels/hydrogen_basics.html

[twicetwice]

You're comparing mass to volume in that last paragraph there. Based on a quick google search, that 1 kilogram of hydrogen is going to take up 3.4 gallons as a cryogenic liquid—so even more as a compressed gas.

Source: http://www.uigi.com/h2_conv.html

[dahfizz]

> Obviously we are not comparing about the weight of an EV compared to an apple or vehicle that doesn't require a battery.

Well, yeah that was my original intention. Teslas get comparable range to ICE vehicles while using less than 3 gallons of gas. That comparison to ICE vehicles demonstrates the efficiency of electric vehicles.