LNA, an aviation industry newsletter, recently came to a very different conclusion [1]. The biggest difference to Wendover Productions's numbers is a hugely higher estimate in the cost of replacing the battery every 5-10 years due to battery degradation.
That sounds like a ridiculous assumption. Airplanes are basically guaranteed to not discharge the batteries lower than 20% for safety reasons. I’m guessing they’ll also not charge to fully 100%, like some BEVs. On fixed routes they could charge only what they need to get to where they’re supposed to go plus the required buffer for emergencies. The batteries will probably also be cooled. So it could be an ideal scenario for battery degradation. There are 10yo Nissan Leafs on the road right now that was pretty much the worst case for battery degradation.
You can also imagine that planes will start operating longer routes and then move to shorter routes as the battery degrades. Since the batteries are large they could get a decent amount of money for them when they’re too degraded for airplanes. They should still be useful for energy storage.
I also think it’s likely that when airplanes go mainstream, they’ll use a different chemistry than the standard Li-ion chemistries we have today. Maybe solid state lithium (Quantumscape?) or sodium ion. So it’s very hard to say how big the degradation problem will actually be.
The cost of replacing a battery is about the same cost as a turboprop engine overhaul, and depending on the battery type and other details, it may occur less often.
Turboprop engines like the PT6 have a Time Between Overhauls of about 3000 hours, maybe longer. At 240 knots, that's 720,000 nautical miles between overhauls. If your electric aircraft has a range of 500 nautical miles and a 1500 cycle life, that's the same time. For an electric aircraft with a 900kWh battery like the Eviation Alice, and a cost per kWh of $170-$300/kWh, that's $150,000-300,000, the same as a turboprop engine overhaul.
Cycle lifes well beyond that are feasible, though, and battery costs are reducing over time.
So, by that article, a fully-loaded turboprop (let's say 19 100 kg passengers, 4900 kg airframe, 320 kg fuel, 308 kg reserve fuel) flying 200 nm weighs ~ 7500 kg and consumes just under 4 MWh of fuel, of which 1 MWh is useful work.
The battery model will weigh at least twice that for the same useful work, so how the hell does it fly as far? Could it actually fly the mandated 100 nm + 30 min contigency*
ridiculous quote of $/kWh of batteries, poor analysis of degradation which is way more complicated than they assume, also you should understand that soon carbon will have a price, airlines won't have a freeride forever
Anyone get a weird feeling about Wendover? I used to think he was a decent authority until I watched his channel Half As Interesting.
Maybe he hires a writer, but his sarcastic joking nature comes off as extremely sincere and authoritative. This makes me question how solid his Wendover points are. He has a commanding voice and we believe him.
I suspect it was in jest, but the reason why is that he is obviously immensely passionated about aviation and logistics. He makes really, really good videos about both, I'd recommend his channel to anyone.
PS, I had to vouch for your comment to reply, as it was dead. Had a look through your profile… I think there's often a lot of value in asking simple questions, but a lot of your comment history is just extremely low value (eg. correcting people's spelling). If you don't have anything meaningful to add to a discussion, maybe consider not replying at all.
saddlerustle|4 years ago
[1] https://leehamnews.com/2021/07/01/the-true-cost-of-electric-...
audunw|4 years ago
You can also imagine that planes will start operating longer routes and then move to shorter routes as the battery degrades. Since the batteries are large they could get a decent amount of money for them when they’re too degraded for airplanes. They should still be useful for energy storage.
I also think it’s likely that when airplanes go mainstream, they’ll use a different chemistry than the standard Li-ion chemistries we have today. Maybe solid state lithium (Quantumscape?) or sodium ion. So it’s very hard to say how big the degradation problem will actually be.
Robotbeat|4 years ago
Turboprop engines like the PT6 have a Time Between Overhauls of about 3000 hours, maybe longer. At 240 knots, that's 720,000 nautical miles between overhauls. If your electric aircraft has a range of 500 nautical miles and a 1500 cycle life, that's the same time. For an electric aircraft with a 900kWh battery like the Eviation Alice, and a cost per kWh of $170-$300/kWh, that's $150,000-300,000, the same as a turboprop engine overhaul.
Cycle lifes well beyond that are feasible, though, and battery costs are reducing over time.
yodelshady|4 years ago
The battery model will weigh at least twice that for the same useful work, so how the hell does it fly as far? Could it actually fly the mandated 100 nm + 30 min contigency*
gok|4 years ago
By 2025 batteries are not going to cost 3x more than they cost today.
thunderrabbit|4 years ago
Even if batteries have to be replaced that often now, the technology will continue to improve, becoming both cheaper and more reliable.
Computers used to be the size of rooms and break due to literal insects in them.
hokkos|4 years ago
thunderrabbit|4 years ago
deregulateMed|4 years ago
Maybe he hires a writer, but his sarcastic joking nature comes off as extremely sincere and authoritative. This makes me question how solid his Wendover points are. He has a commanding voice and we believe him.
citrusybread|4 years ago
doesn't help that it feels like clickbait, at least for HAI, and most of them can be summed up with a tweet.
canadianfella|4 years ago
scrollaway|4 years ago
PS, I had to vouch for your comment to reply, as it was dead. Had a look through your profile… I think there's often a lot of value in asking simple questions, but a lot of your comment history is just extremely low value (eg. correcting people's spelling). If you don't have anything meaningful to add to a discussion, maybe consider not replying at all.