Methanol also seems to be edging it over ammonia as what shipping companies are going for:

https://www.hydrogeninsight.com/transport/why-shipping-is-opting-for-green-hydrogen-based-methanol-over-ammonia-despite-much-higher-fuel-costs/2-1-1577939

"Methanol is more expensive to produce, but ammonia is more expensive to handle."

This is somewhat to my relief, as ammonia can be pretty nasty.

@SJC

Pretty much level pegging then between ammonia and methanol production in terms of their energy content.

dme 28.8 MJ/kg 19.3 MJ/litre

Making 1 ton of ammonia releases 1.6 tons of CO2
So when people say using NH3 ammonia releases no carbon that is not the case

Davemart -
on the offchance this may be news, the Standard Industry Practice for UK methanol production before the fossil gas era was via Native Coppice Forestry for charcoal retorts, whose hydrocarbon offgasses were reacted to methanol. In its day, very big business. Judging by a 1987 NREL report, it would now be very competitive with Olah Process methanol, with each tonne of wood yielding 570kg of methanol.

Three key points of significance:
- the production is highly exothermic and uses no imported energy, and all carbon emissions have to be recovered by the coppice to maintain feedstock supply;

- the charcoal co-product can be used as a Biochar soil amendment for raising crop yields while also sequestering carbon for the very long term;

- NREL put the yield at 57% by weight of feedstock - i.e. subtropical coppice yielding 10.0t Dry Wood /ha /yr should yield 5.7t methanol /ha /yr, while the 2012 joint study by WRI & WFN of suitable land available for afforestation (sans farmland, old forest and special ecologies) identified 1,600Mha.s globally. The potential scale of production is thus far above the foreseeable maximum demand for a renewable liquid hydrogen-carrier in the form of methanol.

Hi Lewis

I don't know much about biological routes to energy production, as at one time the imputs of water, land etc were to put it mildly challenging.

Some of the newer routes, algae etc may make it a different ball game, but they are just pathways I am not very informed on.

As I have pointed out before methanol as a transportation fuel cannot decarbonize this economic sector unless the CO2 is recycled (i.e. captured on board the transport vessel and returned to the methanol production site) or direct captured from the atmosphere. Economical direct capture from the atmosphere still seem like a remote possibility. I have recently read a proposal for capturing CO2 from solid oxide fuel cells (https://news.northwestern.edu/stories/2021/08/the-case-for-onboard-carbon-dioxide-capture-on-long-range-vehicles/) on board ocean going vessels.

To Roger -
While the CO2 released by the use of methanol in transport or stationary roles has to be captured for a carbon neutral outcome, it does not need to be captured at the point of use . I would agree that there is no sign of a Direct Air Capture of CO2 becoming a viable option.

However there is an extremely well proven traditional method of methanol production - that uses feedstock from Native Coppice Forestry whose regrowth has to recover every gram of carbon to provide subsequent harvests of equal size. An outline of this option was posted further up this thread, which may be of interest.

@Lewis

Ammonia is dodgy old stuff to handle, all right, but I am not sure that it should be characterised in the extreme terms you suggest.

We currently produce a couple of hundred millions tons or so a year of it, and although not without problems catastrophies seem relatively rare.

The main point is what is the true disaster area is things like diesel for shipping, which is not only a massive proven killer daily and yearly but tough indeed to decarbonise.

I would therefore argue that even using 100% ammonia from fossil fuels without renewables we would be doing way, way better than present practice.

But of course we don't need to, as ammonia production can be heavily decarbonised.

It looks in any case as though it is considerably cheaper, at least in the short term, to move shipping to methanol than ammonia, which is considerably less problematic.

Some LOHCs also look promising, but the important thing in my view is to get away from the current disastrous situation, and I would many times rather use ammonia, should that prove necessary, than what we do at the moment.

It is rather analogous in my view to the debate about nuclear, due to, again in my view, a completely disproportionate focus on risks.

I find it difficult to see how it can sensibly be currently argued that not having a massive world wide drive to nuclear along the lines of the French, until renewables matured, would not only have saved huge numbers of lives in mining and pollution but would have taken the edge off of climate change.

My view would be that getting too mono-focussed on the risks of one technology leads to poor and unbalanced decision making.

So we can likely largely to better, but ammonia is so incredibly much better than what we are up to at the moment, that undue obstacles should not be put in its way.