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Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

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Re: Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

#131

Post by floxy »

Why do lithium battery prices keep going down? Because the Chinese are subsidizing everything for us? Or that battery production is getting more efficient over time? I guess my spidey sense gets a little tingly when sourcing data from papers published in 2021 and 2022. A.) Covid, B.) 4 year old papers are based on data that is even older, and it seems like things are changing fast with respect to batteries. Not to say that battery-electric planes are coming anytime soon.

https://www.visualcapitalist.com/charted-lithium-ion-batteri...

Re: Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

#132

Post by throw-qqqqq »

kumarski wrote: post #105
Workaccount2 wrote: post #73

Your being a bit disingenuous by not comparing the relative efficiencies of electric vs gas propulsion. Electric motors are ~3x as efficient. They also can recharge by capturing energy during use. In a car for example, you need about 9 gallons of gas in a 33mpg car to get 300 miles. This is equivalent to a 75kWh EV. On paper though, with the conveniently leaving out details math this guy is using (or maybe it's too p…

The energy required to extract, process and manufacture lithium batteries (70% of total lifecycle energy occurs before the vehicle moves) Grid transmission losses (5-8% average, up to 15% in extreme conditions) Battery charging/discharging efficiency losses The dramatic efficiency reductions in adverse conditions (33% range loss in cold weather) For aircraft and marine applications specifically (which was my focus),…

I agree that planes are not likely to be electrified in the near future with current tech. Not sure about marine though.

Ships benefit from the square/cube law: square the hull area -> the volume is cubed.

E.g. if you double the size of a ship, the drag increases 4x but it can carry 8x the weight.

So larger ships are more efficient than smaller ones (at carrying containers/bulk/etc at scale).

Here in northern Europe, we already have electrified car carrying ferries etc.

Ocean going vessels will take longer though.

Re: Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

#133

Post by metalman »

lolc wrote: post #99
sokoloff wrote: post #12

Earlier quoted context omitted.

Aircraft getting lighter as they burn off fuel is a feature. Lithium energy storage doesn’t get lighter as it discharges, meaning the aircraft doesn’t get more efficient as stored energy decreases and the landing weights/speeds are higher than a comparable fossil fueled aircraft. I’m more hopeful that synthetic jet fuel will be a practical solution than batteries for long-range flight.

> meaning the aircraft doesn’t get more efficient as stored energy decreases While I read that, I imagined booster packs detaching from airplanes when they reach cruise height. In my mind they look like heavy quadcopters stuck to the wings. They would cycle back to the airport for charging before assisting the next climb.

the thing with all of that obvious engineering detail, is that it is old, very old, and liquid fueled heat engines have very little room for improvement, while, electricity storage mediums, have vast potential for improvement. Solid state batteries are already bieng investigated for use as structural components, and super capacitors have the potential to weigh very little, and are only waiting for a technology that allows for higher and higher internal surface area, something that many other technologys can make use of, and is bieng sought after by many research teams. Jet A will remain Jet A, and hot section components in jet engines are more or less stuck where they are ,and the best theoretical improvements, are not large. So there is a certain inevitability about how this plays out.

Re: Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

#134

Post by BLKNSLVR »

testing22321 wrote: post #29

“Gasoline’s dirty secret: it’s toxic, expensive and using it kills the planet.” This type of framing is utterly pointless, and tries to make out like electric propulsion shouldn’t be used for anything because it’s not ideal for everything. Even if we never get to everyday electric planes (debatable), that has zero bearing on the fact electric cars are already excellent for many uses.

It took my wife and I actually buying an electric car and running it for a few months to actually convince family members that electric cars are a worthwhile technology.

They were fervently against us buying one, so much so that we had to avoid conversation about it and outright lie to them about our intentions.

"You can't take it on a driving holiday."

Yeah, we'll manage with one of our other two existing cars for that, like we have when we've taken one of our previous once every couple of years driving holidays.

"You can't tow with it."

Thank fuck, I hate towing and I can't remember towing anything in the last 15 years.

The electric car, a Nissan Leaf, is perfect for 99% of our use cases. The whole family love it. It's our "first in best dressed" car.

Even smart people are fucking stupid about plenty of things.

Re: Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

#135

Post by seb1204 »

retrocryptid wrote: post #59
buckle8017 wrote: post #20

Earlier quoted context omitted.

Economics. The solar panels would be more expensive than bunker fuel. Sails would be cheaper.

it might be fun to try to make a modern wooden sailing ship cargo fleet. maybe with an emergency diesel engine in the back.

It's been done, however the scale of modern Panamax containerships is baffling and most people underestimate their size.

https://www.newscientist.com/article/2445620-worlds-largest-...

Re: Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

#136

Post by Retric »

svnt wrote: post #117
Retric wrote: post #79

Earlier quoted context omitted.

Solar power being useful doesn’t require 100% of propulsion to come from solar panels. You see solar panels added to a wide range of boats because even bunker fuel isn’t free and panels are light for the power they provide over even a few days. A current 399.9 * 61.3m container ship doesn’t need panels everywhere to benefit, but the potential savings is significant if they do.

This is unfortunately not true because of the dynamics of diesel engines: there is by design surplus energy relative to requirements from running them at efficient operating points. Otherwise the ship is not a good ship.

You can always scale design to fit reduced demand. Also, loss of efficiency is more than made up for with vastly lower energy demand.

“Lowering speed reduces fuel consumption because the force of drag imparted by a fluid increases quadratically with increase in speed. Thus traveling twice as fast requires four times as much energy and therefore fuel for a given distance.”

https://en.wikipedia.org/wiki/Slow_steaming

“Container ship Emma Mærsk in Aarhus, 5 September 2006 Mærsk Line's E-class container ships such as the Emma Mærsk can save 4 metric kilotons of fuel oil on a Europe-Singapore voyage by slow steaming.[5] At typical fuel prices of US$600-700 per tonne,[4] this works out to a saving of US$2.4-2.8 million on a typical one-way voyage. Maersk's Triple E-class container ships were designed for slow steaming and have less powerful engines than their predecessors.[5]”

Re: Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

#137

Post by ikkun »

kumarski wrote: post #105
Workaccount2 wrote: post #73

Your being a bit disingenuous by not comparing the relative efficiencies of electric vs gas propulsion. Electric motors are ~3x as efficient. They also can recharge by capturing energy during use. In a car for example, you need about 9 gallons of gas in a 33mpg car to get 300 miles. This is equivalent to a 75kWh EV. On paper though, with the conveniently leaving out details math this guy is using (or maybe it's too p…

The energy required to extract, process and manufacture lithium batteries (70% of total lifecycle energy occurs before the vehicle moves) Grid transmission losses (5-8% average, up to 15% in extreme conditions) Battery charging/discharging efficiency losses The dramatic efficiency reductions in adverse conditions (33% range loss in cold weather) For aircraft and marine applications specifically (which was my focus),…

70% of total lifecycle energy occurs before the vehicle moves

that's partially because the operating costs are very low, which is a good thing.

Grid transmission losses

what about the cost of shipping gasoline?

The tires on an electric vehicle[...]

this is part of what leads me to think your entire article is just anti-EV sentiment wrapped in a facade of being about planes, so you can point to the planes when people criticize it. most people here are not arguing that it makes sense to put batteries in planes, they're pointing out the very obvious inaccuracies in basic calculations like the $5/KWh the article leads with. and I also take issue with the un-cited sources (a link to a home page is not a cited source).

Re: Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

#138

Post by Panzer04 »

Pretty classic arguing a point no one makes.

Sea and air electric travel is and has always been the final frontier of transport electrification, and no one expects it to come easily. As tech currently exists I don't see a path for battery technology to supercede existing fossil-fueld solutions. That could change though if newer, more advanced battery tech comes out but for now it's just not really commercially feasible.

I wouldn't trust a thing this guy says about it though, because he appears to know essentially nothing about the topic he is talking about. I'm glad he includes that tweet at the start because it demonstrates his own lack of knowledge instantly. It's hilarious that he actually is off by a factor of ten :D

Re: Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

#139

Post by lawrenceduk »

pfdietz wrote: post #118
wkat4242 wrote: post #82

The profitability will come when we factor in the environmental damage in the prices. However the elephant in the room at least for aviation is that the energy per kg is about 50 higher for kerosene than for lithium batteries. A very large part of an airliner is fuel already. 50 as much? Not gonna happen. This will remain a really short range thing unless a really amazing breakthrough happens.

One possible path is the hybrid aircraft, where combustion turbines or fuel cells produce electric power that drives small ducted fans via electric motors. The enabling technology here is superconductors. Airbus is working on superconducting motors and generators for such hydrogen-powered aircraft. One can imagine regenerative braking in the fans, for example to recover energy as aircraft descend, and also with batte…

Pilot here, I don’t think this is right.

Aircraft typically operate at 80-100% power output. It’s not the average 20% power output of your car.

Weight is pretty much everything, the savings from regenerative braking in an aircraft are almost 0% but the cost of enabling it is some tons.

This tech makes loads of sense in a car but I’ve never flown an aeroplane in stop-start traffic because that’s not how the sky works.

Re: Electric Propulsion's Dirty Secret: Why Lithium Can't Fly (Or Float) Profitably

#140

Post by dontlikeyoueith »

sitharus wrote: post #89
toast0 wrote: post #38

I suspect that there's niches where battery electric boats and maybe planes do make sense. My state's ferry system is investing in electrifying, because they project it reduce operating costs. The 'easy' part is moving towards hybrid systems that can move with diesel or battery; this is projected to save fuel even without shore charging. The hard part will be making shore charging work. Our grid is mostly hydro, so s…

Where I live companies are moving to electric ferries because they’re cheaper to operate, require less maintenance, and are much quieter for the passengers. Plus they don’t emit any exhaust fumes while idling at the dock. The port also has an electric tug boat, which their reports say is very handy because it changes power output much faster than diesel tugs. Charging times are not a factor according to their reports…

> the minerals in batteries don’t disappear after use.

For all practical purposes they might, depending on how the batteries are disposed of.

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