Electric Airplanes

[ncbill]

Don't expect electric planes, it's not the technology for clean flight. Think something more like hydrogen power.

In electrical terms, the energy density of hydrogen is equal to 33.6 kWh of usable energy per kg, versus diesel which only holds about 12–14 kWh per kg. What this really means is that 1 kg of hydrogen, used in a fuel cell to power an electric motor, contains approximately the same energy as a gallon of diesel.

Hydrogen blasted the space shuttle into orbit!

The problem is that to make a hydrogen-burning, fuel-cell vehicle (FCV) with roughly the same range as a gasoline fueled vehicle (~400 miles) requires a special, high-pressure (~10,000 psi) carbon-fiber-reinforced tank that last I checked by itself costs nearly as much as a compact car.

You can use a cheaper metal tank at much lower pressure, but then the range drops to the point that you might as well just put a compressed natural gas (CNG) cylinder (~2,500 psi) in the trunk of an ICE-powered vehicle as the fuel instead of gasoline.

 

[NW-Bound]

^^^ The problem with storing hydrogen has not been solved, even though there was talk about hydrogen-powered cars back during the oil embargo of the 70s.

So, even when we can get dirt-cheap RE from solar or wind energy from which to make hydrogen, the problem has always been how to store it. Hydrogen is not that good a storage medium, because it is not easily liquefied.

There's talk about generating hydrogen by electrolysis, and then to use hydrogen to make hydrocarbons to store as liquid fuels. Chemists already know how to do this. It's just the matter of getting cheap energy, because the problem is only economic and not technical.

Oh, wait. Did they say hydrocarbons? Carbon? Then, you will have the CO2 which is now a cursed word. Hah!

 

[Koolau]

^^^ The problem with storing hydrogen has not been solved, even though there was talk about hydrogen-powered cars back during the oil embargo of the 70s.

So, even when we can get dirt-cheap RE from solar or wind energy from which to make hydrogen, the problem has always been how to store it. Hydrogen is not that good a storage medium, because it is not easily liquefied.

There's talk about generating hydrogen by electrolysis, and then to use hydrogen to make hydrocarbons to store as liquid fuels. Chemists already know how to do this. It's just the matter of getting cheap energy, because the problem is only economic and not technical.

Oh, wait. Did they say hydrocarbons? Carbon? Then, you will have the CO2 which is now a cursed word. Hah!

At some point in our bid to stop using hydrocarbons, we will have to make some tough choices - most of which boil down to cost. It's true that H2 has a lot of advantages as a fuel - especially when it comes to producing CO2 - because it doesn't produce CO2 (at least not during the combing of O2 with 2H2. The process of PRODUCING H2 might indeed involve producing CO2.)

But, back to Hydrocarbons for a moment. Pretty much the "ideal" hydrocarbon is methane (the main ingredient in Natural Gas). Because it is 4 atoms of H and one atom of C, burning it produces the least amount of CO2 of any of the Hydrocarbons per BTU. In fact, burning methane instead of coal reduces CO2 emissions by almost half over coal per BTU produced. Vs Kerosene, Gasoline, Fuel Oil and the like, Methane reduces CO2 by roughly 25 to 30% per BTU.

It's not too difficult to imagine using methane (or natural gas) as a transportation fuel - we do it already in many applications. It might even be cheaper than using gas/diesel when it all shakes out (both in fuel cost AND in producing cars with the appropriate tanks, delivery systems, injection or carburation, etc.) Maybe a baby step (Methane) would be better than waiting for the baby to grow up to be a runner (H2). Oh, and though there would be some engineering issues, Methane absolutely COULD propel airliners - it might reduce their range due to weight of storage tanks, but it's likely we could engineer around a lot of the issues. Just a thought as YMMV.

 

[NW-Bound]

At some point in our bid to stop using hydrocarbons, we will have to make some tough choices - most of which boil down to cost. It's true that H2 has a lot of advantages as a fuel - especially when it comes to producing CO2 - because it doesn't produce CO2 (at least not during the combing of O2 with 2H2. The process of PRODUCING H2 might indeed involve producing CO2.)

But, back to Hydrocarbons for a moment. Pretty much the "ideal" hydrocarbon is methane (the main ingredient in Natural Gas). Because it is 4 atoms of H and one atom of C, burning it produces the least amount of CO2 of any of the Hydrocarbons per BTU. In fact, burning methane instead of coal reduces CO2 emissions by almost half over coal per BTU produced. Vs Kerosene, Gasoline, Fuel Oil and the like, Methane reduces CO2 by roughly 25 to 30% per BTU.

It's not too difficult to imagine using methane (or natural gas) as a transportation fuel - we do it already in many applications. It might even be cheaper than using gas/diesel when it all shakes out (both in fuel cost AND in producing cars with the appropriate tanks, delivery systems, injection or carburation, etc.) Maybe a baby step (Methane) would be better than waiting for the baby to grow up to be a runner (H2). Oh, and though there would be some engineering issues, Methane absolutely COULD propel airliners - it might reduce their range due to weight of storage tanks, but it's likely we could engineer around a lot of the issues. Just a thought as YMMV.

Methane is easier to liquified than hydrogen, but its boiling point is still quite cold at -259F (-162C). It is not easy to store like gasoline, or easily liquified like butane and propane.

But it occurred to me that perhaps methanol is a lot nicer to work with, and can be made from methane, by adding oxygen.

Methane: CH4
Methanol: CH3OH

Chemists know how to turn methane into methanol. I don't know how costly this process is. In theory, the problem is already solved.

PS. The drawback is methanol has less than 1/2 the energy density of methane. That extra oxygen atom is dead weight.

Methane: 55.5 MJ/kg
Methanol: 22 MJ/kg

 

[Koolau]

Methane is easier to liquified than hydrogen, but its boiling point is still quite cold at -259F (-162C). It is not easy to store like gasoline, or easily liquified like butane and propane.

But it occurred to me that perhaps methanol is a lot nicer to work with, and can be made from methane, by adding oxygen.

Methane: CH4
Methanol: CH3OH

Chemists know how to turn methane into methanol. I don't know how costly this process is. In theory, the problem is already solved.

PS. The drawback is methanol has less than 1/2 the energy density of methane. That extra oxygen atom is dead weight.

Methane: 55.5 MJ/kg
Methanol: 22 MJ/kg

Yes, methanol is a relatively poor transportation fuel. It's heavy for its lack-luster heat content. It is relatively corrosive as well. BUT, it's a dramatically better fuel for aircraft than electricity stored in the batteries known or even theorized today. Sad when a "poor" fuel like methanol is much better than the elegant "batteries" that we hope for. As always, I guess there could be a "miracle" but I wouldn't count on it so YMMV.

 

[NW-Bound]

I just ran across this report on Northvolt/Cuberg, a startup that is developing a lithium metal battery. Better-known Quantumscape is also developing a lithium metal battery, but the two companies have different approaches, which are beyond me as a layman.

What makes me share this video here in this thread is that Cuberg said the market first targeted for its battery is short-haul aviation. It said aviation really needs a battery with a higher energy density than what is provided by the common lithium battery, and can afford the higher price. Eventually, the price will get lower where they can sell it for cars.

 

[tulak]

Read an article about Eviation, who is building a commuter EV plane. 9 passenger, 440nm range. That won’t get you very far, but can work well in dense areas (Europe/Asia/East US)? It looks like they are using existing tech.

https://www.eviation.co

Edit to add the article: https://www.geekwire.com/2021/real-...-eviation-set-fly-battery-powered-plane-year/

 

[stephenson]

Not sure current tech will meet that sort of aircraft and flight profile.

 

[CardsFan]

https://www.foxbusiness.com/lifestyle/united-airlines-purchase-electric-planes-heart-aerospace

United Airlines is placing a new bet on electric air travel as part of its goal to reduce its greenhouse gas emissions 100% by 2050.

The company's investment arm, United Airlines Ventures (UAV), as well as its partners Breakthrough Energy Ventures (BEV) and Mesa Airlines, have announced a new investment in Gothenburg, Sweden–based electric aircraft startup Heart Aerospace, which will fast track the development of its ES-19 electric aircraft to begin commercial service by 2026.

Looks like UA is making a commitment to go electric.

 

[NW-Bound]

Not sure current tech will meet that sort of aircraft and flight profile.

It appears to me many startup companies are revving up to do a design and build a prototype, with the expectation that the technology will deliver the new battery that they need. That allows them to get a head start on competition, but if the battery technology does not deliver, there will be a lot of hurting.

https://www.foxbusiness.com/lifestyle/united-airlines-purchase-electric-planes-heart-aerospace

Looks like UA is making a commitment to go electric.

An excerpt from the link:

Once operational, the battery-powered aircraft is expected to transport customers from up to 60 miles away, and at speeds of up to 150 miles per hour.

That's a mightily short flight!

 

[CardsFan]

It appears to me many startup companies are revving up to do a design and build a prototype, with the expectation that the technology will deliver the new battery that they need. That allows them to get a head start on competition, but if the battery technology does not deliver, there will be a lot of hurting.

An excerpt from the link:

That's a mightily short flight![/QUOTE]

OH, I agree. I think it is more PR than anything real. Kind of like the pledge to reduce greenhouse gasses by 100% by 2050.

Corporate big shots promise something 30 years in the future, but they only plan on hanging around another ten years.

 

[stephenson]

Yeah - not much of a bet if it doesn’t affect their real business - just PR and marketing.

 

[Koolau]

Yeah - not much of a bet if it doesn’t affect their real business - just PR and marketing.

Yes, any "plan" with a 30 year time-frame can pretty much be discounted as PR. No one who makes such a plan will be around in 30 years to be criticized for not meeting said plan. It's all smoke and mirrors - especially if you understand the basics of battery technology. YMMV

 

[jeffmete]

Koolau, got that right!

 

[Sunset]

I'm surprised nobody has suggested battery operated space flight.
Elon already has a headstart

 

[Chuckanut]

I'm surprised nobody has suggested battery operated space flight.
Elon already has a headstart

Does the Electron rocket count?

I can't help but think that in 30 years there maybe another source of electric (or otherwise) power for planes and other vehicles.

10 years ago the idea of landing a booster rocket and reusing it was considered nonsense by most experts in the field.

30 years ago who thought we would have powerful pocket computers that cost only a few days pay to buy.

OTOH, we still can't cure the common cold.

Predicting the future is tough.

 

[NW-Bound]

I'm surprised nobody has suggested battery operated space flight.
Elon already has a headstart

Out in space, the only way to have propulsion is via Newton's Third Law of Motion. You have to carry something with a mass, then eject it backwards to get a force to push you forward.

I guess you can carry a lot of batteries, then eject them out the rear to move forward. However, it would be cheaper to carry slugs of lead to shoot out the rear, as they are cheaper than batteries. Won't work as well as burning and expelling propellants though.

Does the Electron rocket count?

I wonder how Rocket Lab gives its rocket that name. What's so "Electron" about that design?

I can't help but think that in 30 years there maybe another source of electric (or otherwise) power for planes and other vehicles.

10 years ago the idea of landing a booster rocket and reusing it was considered nonsense by most experts in the field.

30 years ago who thought we would have powerful pocket computers that cost only a few days pay to buy.

OTOH, we still can't cure the common cold.

Predicting the future is tough.

McDonnell Douglas worked on the DC-X, a prototype of a reusable single-stage-to-orbit launch vehicle in the 90s. They had successful landings too. Don't know how this project was canceled by NASA.

The 1/3-scaled prototype was built for a measly $60 million. A photo of the 1st landing is linked below.

Progress of CPUs and semiconductor chips is made via gradual improvements of existing processes. They had a roadmap laid out years in advance, I think.

Making a drastically better battery requires some astounding fundamental discoveries. I think that's why it's harder. But what do I know?

 

[Chuckanut]

McDonnell Douglas worked on the DC-X, a prototype of a reusable single-stage-to-orbit launch vehicle in the 90s. They had successful landings too. Don't know how this project was canceled by NASA.

The 1/3-scaled prototype was built for a measly $60 million. A photo of the 1st landing is linked below.

The Everyday Astronaut has a video on why single stage to orbit is not very practical.

In order to drill this point in we’ll teach you all about the tyranny of the rocket equation and help you understand why every orbital rocket, well, ever is multistage.

 

[ejman]

Out in space, the only way to have propulsion is via Newton's Third Law of Motion. You have to carry something with a mass, then eject it backwards to get a force to push you forward.

I guess you can carry a lot of batteries, then eject them out the rear to move forward. However, it would be cheaper to carry slugs of lead to shoot out the rear, as they are cheaper than batteries. Won't work as well as burning and expelling propellants though.

Well, I've seen a few videos of unidentified aerial gizmos that seemingly don't quite follow Newton's third law. Obviously as it was famously said in another context we don't know what we don't know about the universe we live in. It seems we (along with every civilization before ours) think we have it all figured out. Maybe not.

 

[NW-Bound]

Well, I've seen a few videos of unidentified aerial gizmos that seemingly don't quite follow Newton's third law. Obviously as it was famously said in another context we don't know what we don't know about the universe we live in. It seems we (along with every civilization before ours) think we have it all figured out. Maybe not.

Whatever humankind knows to build, it has to conform to the laws of physics as we know them.

If some ETs know how to bypass these laws, we need to befriend them, so they will show us how.

 

[NW-Bound]

The Everyday Astronaut has a video on why single stage to orbit is not very practical.

The single-stage idea is impractical, but the ideas of reusable rockets and recovery by vertical landing were demonstrated by the DC-X.

 

[CardsFan]

Whatever humankind knows to build, it has to conform to the laws of physics as we know them.

If some ETs know how to bypass these laws, we need to befriend them, [-]so they will show us how[/-] before they take over the world.

FIFY

 

[NW-Bound]

^^^ Nah, they would have taken over already anytime if they wanted to, being so much more advanced than we are.

 

[CardsFan]

^^^ Nah, they would have taken over already anytime if they wanted to, being so much more advanced than we are.

And, of course, maybe they looked at us and said "Why would we want them? They can't even play nicely among themselves. But they are fun to watch, you know, like an ant farm".

Wasn't there a Twilight Zone episode something like that?

 

[NW-Bound]

And, of course, maybe they looked at us and said "Why would we want them? They can't even play nicely among themselves. But they are fun to watch, you know, like an ant farm".

Wasn't there a Twilight Zone episode something like that?

Not sure, but there was an episode where at the end it was revealed that the ETs were carnivorous and liked the taste of human flesh.