exchemist

Well, what can one say but "Oh Christ!"😁

Who's the guy with the charlatanic sideburns? 😆

So she went into the garden to cut a cabbage leaf, to make an apple pie; and at the same time a great she-bear coming up the street, pops its head into the shop. 'What! no soap?' So he died, and she very imprudently married the barber; and there were present the Picninnies, and the Joblillies, and the Garyulies, and the grand Panjandrum himself, with the little round button at top; and they all fell to playing the game of catch as catch can, till the gunpowder ran out at the heels of their boots.

The only Travis Trenton I can find is some kind of marketing manager with T-Mobile: https://www.linkedin.com/in/trentontravis?original_referer=https%3A%2F%2Fduckduckgo.com%2F Is that who you mean?

According to this source there are both magnetic and non-magnetic grades of stainless steel and the magnetic grades have poorer corrosion resistance: https://www.eclipsemagnetics.com/resources/are-all-stainless-steels-magnetic/

There could easily be a huge market for it. Hydrogen would be close to a drop-in replacement for methane in domestic heating (you can put up to 25% into the supply today without even changing burners). Also I believe hydrogen is thought to be a good candidate for heavy duty truck transport, for which batteries would be very large and heavy. We already have hydrogen buses in some places. It needs something to kick-start it though - probably government. I don't think, myself, that trying to totally decarbonise shipping is a top priority. Switch to lower carbon liquid fuels in the medium term while you go for other sectors with more impact on total emissions.

IR radiation is of the right order of frequency to set up vibration in molecules which have a dipole (partial charge separation), giving up its energy to the molecule in the process. So this is what makes a molecule absorb in the IR. What you are seeing is absorption due to different modes of vibration of the molecule. CO2 can stretch or it can bend. I rather think the left hand band is the stretch and the right hand one is the bend. So it's not several different species. It's all CO2. In general, the IR spectrum of a given molecule has a number of absorption regions, not just one.

Neither.

No. Woo (or woo-woo), is pseudoscience believed by gullible and ignorant people: quackery. Woo-hoo is the sound emitted by people of a sensitive disposition that have read too many of your silly posts. 😁

I think it would be stored as a cryogenic liquid, much as is done on LNG carriers, but I agree there are hazards, e.g. if there is a total loss of power. This is probably why ammonia is being considered - though even that is pretty nasty if there is a leak.

....and, er, here endeth the rant?😁

I don't understand this at all, I'm afraid.

Why are you now talking about aviation fuel?

Why are you doing this? It sounds bonkers.

Specific energy is energy per unit mass, whereas energy density is energy per unit volume: https://en.wikipedia.org/wiki/Specific_energy I'm assuming they are comparing RFO with cryogenic liquid hydrogen.

I really don't think you can do that calculation. We do not know what the cost of hydrogen produced on this scale will be. That depends on such variables as the cost of electricity, which is notoriously variable and will change as the economy decarbonises, the efficiency of the technologies for hydrogen production, of which there are at least two: green hydrogen from electrolysis, and blue hydrogen from steam reforming of methane plus CCS, and the demand for hydrogen from the various applications that could potentially use it, some of which I listed in my previous post. So neither manufacturing cost nor supply and demand balance can be readily estimated - though I feel sure people investing in the business, like Shell, will have some models. As for the ships themselves, a lot may depend on whether they would burn hydrogen in a heat engine as today or whether a move to fuel cells proves feasible. None of the likely costs of these changes is yet known.

Like @studiot, I'm having some trouble following what you are saying. You can't "negotiate" with electrochemistry or physics. Do you mean "optimising", by reducing losses or something? Also there is nothing fundamental about any of the formulae in this thread so far. All we have covered is the arithmetic to work out a % efficiency, given certain measured inputs and outputs. I think you need to be a bit careful what is meant by efficiency in the context of charging and discharging a battery. I see that @studiot has used it to mean the efficiency with which a given electricity supply, as input to a charging system, results in actual charge entering the battery. So that's the efficiency of the charging process. However the figure of 80-90% I was quoting is the efficiency with which the battery itself stores charge, i.e. the amount of charge you get back out for the amount you put in. This is the charge/discharge efficiency. What is the formula you are referring to?

Just to clarify your point (1), where CO2 appears in a ranking by concentration in the atmosphere is irrelevant. What is relevant is the degree to which a gas absorbs IR radiation. The principal gases in the atmosphere (N2, O2, Ar,) do not absorb at all in the IR. They are transparent to it. Neither N2 nor O2 has a dipole in the molecule for the IR radiation to couple to, which is what one needs to get a molecule to absorb and vibrate. Ar is a monatomic gas, so there is nothing to vibrate and so it can't absorb at all in the IR region. The first gas on a list, in descending order of concentration, that has a dipole and can absorb in the IR is H2O, followed by CO2. So forget about CO2 being "near the bottom" of the list, at "only" 0.04% of the atmosphere. That tells you nothing of relevance in this context.

You flatter yourself.

I don't think that is right. The NASA link I provided seems clear that water in the atmosphere has a warming effect overall. The way I read the extract you supplied is that clouds mitigate the greenhouse warming due water vapour - and maybe prevent it running away. How do you come to the conclusion that water in the atmosphere - in all forms, vapour and clouds - has a net cooling effect?

I'm not sure what all these numbers tell us. The energy content is the same regardless of the fuel used. There is a certain efficiency limitation for the production of hydrogen, depending on how it is produced. Those numbers together tell us how much energy would be needed to fuel all these ships. The amount of hydrogen that one part of one company currently says it can produce is not really very relevant. So much depends on how much money the energy industry feels it can make out of supplying it and a lot of that will depend on what other (higher intrinsic value) applications there may also be for the fuel. In the case of hydrogen there are potential applications in domestic heating and as truck fuel. But in any case, I'm not sure that hydrogen is the right fuel to focus on, at least in the medium term. Hydrogen is currently not the most favoured future option for marine bunker fuel. Here is an article about the options from Bureau Veritas: https://marine-offshore.bureauveritas.com/insight/future-marine-fuels-pathways-decarbonization Decarbonisation will be a process, taking decades and most likely involving a number of intermediate steps. You will see that less carbon-rich hydrocarbons, and/or liquid biofuels, are likely to come into use first. Longer term, hydrogen is one possibility certainly, though not on any scale by 2030, while ammonia may well be preferred to hydrogen, due to the easier storage on board (you can liquefy it). Though to make the ammonia you presumably need the hydrogen anyway, so eventually a lot of it will no doubt be needed, one way or another. (You can make "blue" hydrogen from natural gas, if you capture and store the CO2 generated as a byproduct.) If you are really interested in this subject, there is information available on the internet from organisations such as the IMO and CIMAC (a forum for marine engine designers and builders that I used to attend, when I was still working for Shell).

You are for some reason not getting my point. Clouds are water in the atmosphere, but not all the water in the atmosphere is in the form of clouds. There is also water vapour.

This extract does not say that atmospheric water has a net cooling effect on the earth. What it says is clouds have a net cooling effect. As I understand it atmospheric water has a net warming effect, being a blend of IR absorption by vapour and the cooling effect of clouds. In fact, the extract you posted says without clouds the water vapour might lead to a runaway +ve feedback loop. The net effect of water in the atmosphere is described here: https://climate.nasa.gov/ask-nasa-climate/3143/steamy-relationships-how-atmospheric-water-vapor-supercharges-earths-greenhouse-effect/

Yes, as Ken Fabian and I have been saying, if you put more water vapour into the atmosphere, you don't change anything. To put this another way, the water in the atmosphere is, overall, in equilibrium with the vast excess of liquid water that is in the oceans. Evaporation and condensation and precipitation are occurring all the time. So the net effect of adding water vapour by burning a fuel containing hydrogen is that a tiny bit more rain falls at some point, thus correcting the imbalance that the extra water vapour introduces. HOWEVER, the equilibrium position is temperature dependent. So if a permanent, or long term, greenhouse gas increases the mean temperature a bit, then the equilibrium position shifts, in favour of more water vapour in the atmosphere, which warms it up more than the effect of just the greenhouse gas alone. In this way water vapour amplifies the effects of the permanent or long term greenhouse gases. At least, that's the way I understand the process (I'm not an atmospheric chemist).

No, because water vapour doesn't accumulate. It precipitates as rain. This is what is meant in @Ken Fabian's post above, which says water vapour does not itself cause a warming trend, although it amplifies any warming trend there may be due to persistent greenhouse gases.