Member Info for Fahrenheit451

Thanks for that Jeff - interesting.

In that report Airbus's commitment to devope a commercial hydrogen aircraft by 2035 is talked about as a great positive. I note that recently Airbus has 'paused' that program delaying deployment by up to 10 years - Oops, reality bites?

A quote from the publication Flight Plan on this topic says "In the meantime Airbus is also focusing on more immediate solutions to mitigate the environmental impact of aviation. SAF has emerged as a key priority..... ." And remember, if the fuel is made using green hydrogen combined with carbon from direct air capture (DAC), which is a possible route, then its going to need a lot of electrolyser capacity. That's where ITM comes in hopefully.

Jeff

You and others make many points in response to my comments, too many for me to answer unless I spend all afternoon on this but just to pick up on one point you make, which is "Are you aware that hydrogen has around 33,000 Wh/kg, while lithium-ion batteries typically sit around 200–250 Wh/kg when you account for the full system (not just the cell)? Jet fuel is about 12,000 Wh/kg for comparison." All true but what's one needs to also consider is Volumetric Energy Density which is the energy that can be stored in a given volume. Although H2 has and energy density by mass of approx 3 times that of jet fuel, its enery density per unit volume (if it's in its densist form which is as a liquid) is only abou 1/3 that of jet fuel. That means fuel tanks 3 times the size will be needed for a given flight range compared to hydrocarbon fuel. Planes need to be aerodynamic as well as light and larger tanks means a larger airframe and so more drag whch means they will use more fue so even larger tanks! You see the problem? You assume I advocate batteries in all situations - I don't. Batteries for long haul flights are a non starter and, despite their very rapid development, will probably remain so for a long time.

I belive the solution for decarbonising long haul flying, apart from not doing it, is to use SAF of non biological origin. I won't be as cheap as fossil fuel but if produced at scale in parts of the world with large renewable energy reasources it won't be much more expensive. It has the great advantage of been a drop-in replacment for current fuels with no need for new distribution, storage and fueling systems and no need for new aircraft designs and engines.

There is a huge need for low carbon hydrogen and ITM is in the forefront. Having said that the article (FCEVs verses BEVs) is full of misleading comprisons such as a H vehicle charged directly from windfarm has a lower C footprint than a BEV charged on a fossil fuel heavy grid. Well that's not supring! How about a like for like comparison. Before someone says 'so why is 100s millions being invested in H transport then' the answer is politics.

Pushed in 45k just after the open. Looks like it helped to stop the fall. More of that to come if necessary!

Jeff

"The entire push for hydrogen is a scam...". I didn't say that either. 100 million tons of H2 is currently used by industry. Almost all of it is produced from natural gas using SMR and the resultant CO2 is dumped into the atmosphere. This needs to be urgently replaced by zero emission hydrogen and green would best. BTW there is a lot of politics around the hydrogen economy. Just look at the government's support for CCS.

Troublesome

You miss my point. I didn't say hydrogen can't be stored or even that it can't be stored at scale. The problem is achieving the high energy density at reasonable weight and cost needed for vehicles and aircraft or for transportation. Talking of pipe lines - far better to transport the energy in the form of electricity and then generate hydrogen by electrolysis at the point of use for most situations.

Jeff

"the challenges are being solved" but can it be done economically. Cooling to -252C (as is needed for liquid hydrogen) is energy intensive and needs expensive gear. I didn't say it wasn't possible. The fundamental physical differences between hydrocarbon fuels and pure H2 cannot be "solved".

Assumptions.

Jeff

I have a plastic can of petrol in my shed. Please describe the containment system if I were to store the same amount of energy in the form of H2, and it's estimated cost. My petrol can cost £6.

Bilbo

No. It's physics.

Sure it's possible but it's energy intensive and the necessary equipment is expensive, that is compared to fuels that are liquid at atmospheric pressure and at typical outdoor temperatures.

Bilboburglar

I'm new here, 1st post so I don't expect I'll last long! But regarding H2 ease of use: Yes sure it's easy to use until you either have to stuff enough of it into a vehicle or aircraft to get reasonable range (cryogenic or extreme pressure) or transport large amounts over long distances (pipes or tankers). These are serious issues with H2 as an energy carrier.