People down here acting like $5 to keep 25,000 lbs in the air for 30 minutes is not a milestone worth announcing.
“Be perfect NOW” 🤣
Because they didn’t. And anyone that is capable of critical thought can easily take the few numbers they provide in the article and do some simple calculations.
They claim the motors pull more than 1mw of power. So using 1 mw for 30 minutes is 500kWh. That means they paid 1 cent per kWh. (Spoiler. They dont)
And nowhere, does it say the plane weighted 25000 pounds. It says it “can exceed” 25000 pounds. But by no means does that mean that’s what it weighted in this test.
The most likely scenario is that the plane was bare minimum rather than maximum. I doubt even passenger seats were installed.
This seemed intuitively wrong to me (like, way too low a cost), but: 25,000 pounds moving 100 mph is equal to 11,331,007 J of kinetic energy. Since 3.6 million J equals 1 kWh and 1 kWh on average costs $0.17, that means you could accelerate 25,000 pounds to reasonable bare minimum flying speed for about fifty cents (not considering efficiency of the machinery). My mind still can’t process this, but math is math.
On the other hand, looking at it from a potential energy perspective it’s a bit more expensive. 25,000 pounds at a cruising altitude of 10,000 ft. (still quite low from an airliner perspective) is about 339 million J, 94 kWh or about $16 – the cost of lunch at MacDonald’s.
Since a plane requires the most thrust at takeoff, you could use ground-based catapults to get the plane to takeoff speed (or faster even) and then you could carry smaller batteries and propelling machinery. For extra fun, you could have landing planes snag a wire and use their momentum to accelerate a plane taking off.
To save even more weight, since you’re going airport-to-airport you could leave off the landing gear and just have the planes come down on a bouncy trampoline-like surface. If you think that’s batshit crazy, the British actually experimented with this idea for their aircraft carriers in the 1950s.
Edit: to make these numbers more realistic I’m going to assume something like a 737, which can weigh something like 150,000 pounds fully loaded (this includes fuel but you’d need batteries instead for an electric plane). Getting this to a 150 mph takeoff speed would take about 100 million J (getting it then to a cruising speed of 500 mph would be another 233 million J, but that’s pretty minor compared to the other costs). Climbing this plane to 30,000 ft would take 6.1 billion J. Resisting a drag force of 5000 pounds (about what a 737 experiences at cruising speed at 30,000 ft) for 500 miles (the distance from Cleveland to New York City) would need 17.6 billion J. Assuming landing is free (fuck TANSTAAFL) that means a typical trip needs 23.8 billion J or 6618 kWh or $1125. Assuming a real-world efficiency of 25% means the actual cost would be $4500 (which is in the ballpark of what jet fuel costs). Assuming 200 passengers, that’s $22.50 per person. Not exactly “$5 of electricity” but surprisingly small.
Feel free to check my math, my brain hurts.
One important caveat to this. It costs less than 17 cents to generate 1 kwh. Closer to 3 cents really. But that’s the cost of making the electricity, getting that electricity to a house or charger or what have you costs more. Since energy is a for profit industry they tack all the logistics costs to the client buying the electricity.
So your math is spot on but I fear the amount of markup on the electricity will be massive especially since it’s for a business let alone an airline.
National average it’s 55¢ to run 3kw on 3phase electricity for an hour. Offshore areas like Hawaii and Alaska see higher costs like 1.60$/hr per 3kw on 3phase electricity but Alaska has a higher natural gas usage and Hawaii is further away from the CONUS electrical grid. National average per 24/hrs of charging is a little over 13$ with 3kw at 3phase.
And yet it still costs me 30 dollars to charge my car in Georgia and in a state like new York it’s 60 to 100 dollars.