Any option involving batteries requires either massive or phenomenal improvements in battery technology. This will not happen within 20 years, it might not happen in 100, it might not happen at all.
Conclusion: It's not happening in my lifetime, it's probably not happening in my [putative] children's lifetime. Perhaps there will be short haul (~100 nm) electric commercial flight just within my lifetime.
You also mentioned fuel cells. They have the same problem as batteries that they must carry both their fuel and oxidizer.
The only reasonable battery powered air travel I can think of is a zeppelin style as the buoyancy of the aircraft doesn't require fuel, the problem then is a long haul flight will take a week!
Conclusion: It's not happening in my lifetime, it's probably not happening in my [putative] children's lifetime. Perhaps there will be short haul (~100 nm) electric commercial flight just within my lifetime.I think Harbour Air is operating a modified Beaver on electric-only from Vancouver BC to Victoria, I'm not sure if it's truly commercial or for private use, it seems to me the FAA certs to do it carrying the public would be onerous to get.
I had a search for the flights in question and it looks like this is still at the trying to get approval stage. They've got a plane, they've run test flights and I can see lots of re-hashed press releases for that, but none for having got approval.
(IE, when there just are no fossil fuels available at all)
The majority of electricity serving the majority of the world's population came from burning fossil fuels, and the power plants have an efficiency of around 40%, while a jet engine has around 80% efficiency at cruising speed and altitude.
Electric plane, is thus not very eco friendly after all, unless it enables new paradigms like small group or personal hops between short locations where normally cars would have to burn a lot of fuel to wait in a traffic jam.
To me, this is go (very) small or go home.
There is a current trend in thinking one alternative to batteries would be to store energy as a "carbon-free" fuel like hydrogen. Except that producing hydrogen takes electricity (back to blueskull's point), and the process is not much efficient either. But even so, I'm not sure converting hydrogen to electricity via some kind of fuel cell and use electric engines would make much sense. Wouldn't using hydrogen directly to power engines be more efficient? So, that still wouldn't be electric flight.
But since for that to really happen and not be useless, we would need means of producing huge amounts of electricity in a clean way, and since we are still very far from that goal, I think that is what we should focus (and invest) on. Not on building electric planes that make no sense at the moment. Because THAT is, IMO, actually the easy part.
I'm not quite sure what you're trying to say here.
"Liquid Natural Gas" is a fossil fuel. The methane used to heat millions of homes is fossil fuel. A tiny proportion is biogas from fermenters. There is no technological process for turning CO2 + H2O + energy into methane without involving good old fashioned agriculture and rather a lot of waste along the way. We're running out of land for agriculture to feed people, we certainly can't afford the land to make enough methane to keep the world's planes in the air, homes heated and so on.
I'm not quite sure what you're trying to say here.
"Liquid Natural Gas" is a fossil fuel. The methane used to heat millions of homes is fossil fuel. A tiny proportion is biogas from fermenters. There is no technological process for turning CO2 + H2O + energy into methane without involving good old fashioned agriculture and rather a lot of waste along the way. We're running out of land for agriculture to feed people, we certainly can't afford the land to make enough methane to keep the world's planes in the air, homes heated and so on.
There has been since 1897 https://en.wikipedia.org/wiki/Sabatier_reaction
Also not keen on "over population, running out of land" outdated alarmism. Definitely aware of running out of historical energy resources and ever increasing energy demand + climate change but over population and food supply (apart from instability due to climate change) is not a current issue everywhere apart from Africa. Getting off topic though.
I'm not quite sure what you're trying to say here.
"Liquid Natural Gas" is a fossil fuel. The methane used to heat millions of homes is fossil fuel. A tiny proportion is biogas from fermenters. There is no technological process for turning CO2 + H2O + energy into methane without involving good old fashioned agriculture and rather a lot of waste along the way. We're running out of land for agriculture to feed people, we certainly can't afford the land to make enough methane to keep the world's planes in the air, homes heated and so on.Of course there is>
https://www.storeandgo.info/demonstration-sites/germany/
Name a commercial plant using it, producing gas for sale (or even on-site use) at a cost equivalent from buying it from normal sources and in commercial quantities. It has to be a practicable process, not merely possible, that operates economically at the scales of current and proposed world usage. One assumed that an intelligent person would take that as read in the circumstances under discussion. And where does one find a convenient source of concentrated CO2 that isn't a plant burning fossil fuel to produce energy, a cement works, a brewery or a similar primary user of either energy or biomass? One might like to examine the thermodynamics of the first listed to figure out why that isn't a runner for practical purposes.
There is no technological process for turning CO2 + H2O + energy into methane without involving good old fashioned agriculture and rather a lot of waste along the way.
The point was a counter to the claim:There is no technological process for turning CO2 + H2O + energy into methane without involving good old fashioned agriculture and rather a lot of waste along the way.
You might say you meant it differently but anyone reading it could take that to mean it just doesn't exist not it doesn't practically exist.
You can go start a new thread somewhere else if you really want to discuss population and land use.
Edit: I mostly saw that one point above that was patently false, I don't have much to comment on otherwise for the main subject.
We're going to need to make our electricity production systems renewable too, regardless of what we do for transportation, and this is a relatively 'solved' problem at this point, just requiring investment.
We're going to need to make our electricity production systems renewable too, regardless of what we do for transportation, and this is a relatively 'solved' problem at this point, just requiring investment.
Is it? Really?