JLR Q2 Losses

[miketomcat]

I'm interested to see the Munro installation as it's basically defender underneath. So whatever they do could go into a defender with a few tweaks.

Mike

[Snagger]

21 hours ago, reb78 said:

I guess being able to use 4th a lot makes it easy on the gearbox.

I just think our vehicles in particular are going to be the easy ones to convert. There are places that batteries could be located without affecting any space inside the car at all and the engine bay lends itself to easy installation of a motor. If someone could invest in the R&D I would have thought there was a fairly large market in LR world (I mean old LR, not the new fangled disco/rr ranges...)?

Quite.  No existing electronics to interface with the retrofit kit, plenty of voids for batteries with adjacent structural attachment, and those voids being mostly rectangles and cubes that make packaging easy make Series vehicles and early Defenders ideal candidates, especially with the standard gearing of a Series being so appropriate for an electric motor, the lower diffs great for torque and the high motor RPM capability (as compared to the 4250/4500 limit for the four cyl LR engines) not needing overdriving gears (separate, like for LT76 or internal 5th like later units) or raised diffs, so top speed should be good on a standard transmission.
 

 If you don’t go for other mods like PAS, it keeps the electrical loads down too, though with all the battery weight, some sort of boosted brakes would be needed (the vacuum servo assisted SIII system should be OK, but you’d need an electrical vacuum pump).  But no EAS, PAS, ABS/ETC, electronic transmission or enormous cabin power loads would all help offset the aerodynamic inefficiency.  The Series vehicles are also lighter than the later stuff and have less drag on the transmission, having selectable 2wd rather than a centre diff which will sap a little power (especially if an LSD like the Borg Warner units or an ATB retrofit LT230).  It may even be worth Free-Wheeling Hubs (🤮).  Even the cab heaters of the Series models, usually being in a poor state, have trained their drivers not to use them much - EVs use seat heating in preference to air heating as it is much more efficient; it’s as if LR foresaw this in the 50s! 

[Superpants]

As I promised, I've finally written up my thoughts and observations on Hydrogen use as a fuel. Apologies it's taken ages to get round to this- Christmas kind of got in the way!

As an opening point, Fuel Cell Electric Vehicles (FCEV)s are Battery Electric Vehicles with additional components, and a reduced sized battery pack. The battery is necessary to start the fuel cell stack and to take account of the short duration variations in power needed by a vehicle- a finite time exists to ramp up power from the fuel cell stack as it's output is related to the gas flow in, both H2 and air.

In my opinion, Hydrogen is not a viable or sensible solution for personal transportation, or for many of the other areas where we currently use liquid fuels (petrol, diesel, fuel oils) or natural gas. There are use cases where it does make some sense, but I see these as only a very small proportion of the total. There is a good analogy of Hydrogen being touted as the 'Swiss Army Knife' of solutions. Much like the Swiss Army Knife it COULD be used as an energy carrier for lots of these tasks, but it probably SHOULDN'T for most of them as there is a better option available. See the link for an illustration;

https://www.linkedin.com/pulse/clean-hydrogen-ladder-v40-michael-liebreich/

There are a significant number of challenges which have to be overcome with Hydrogen;

Efficiency & Green Hydrogen

Many hydrogen proponents start the conversation with something along the lines of "IF we use excess electricity to hydrolyse water then the solution is green". Whilst this is true, the electrolysis of water is highly inefficient- Peak efficiency is around 50%, and due to the electrochemistry of the reaction can't get significantly better than this. The conversion efficiency in the fuel cell back to electricity is in the range of 40-60% if a Proton Exchange Membrane (PEM) cell is used (currently the only practical cell for automotive use).

If we ignore all the other losses in managing and distributing the gas, the best efficiency from electricity in to useful power at the wheel is around 25%. Once the distribution and any other losses are included, the efficiency will be less than 20%

If we compare this with an BEV- transmission and distribution losses will be less than 10% and the efficiency of charging batteries and then delivering power from battery, through inverter, motor and drivetrain to wheel will be around 90%, we will see an overall efficiency of around 80%. (Numbers are all approximate due to difficulty of pulling accurate figures together that compare directly- there are studies that attempt this though).

If we use green hydrogen, and the only factor in play is commercial, this efficiency difference alone would be enough to stop FCEVs in their tracks as they would be some 4-5x the cost to run per mile than a BEV! With the exception of very limited uses where paying a premium for increased range (and/or reduced fuelling/ charging) would be justifiable, for example some military vehicles or agricultural vehicles, this cost difference would be prohibitive.

Greenwashing

Whilst we could generate Hydrogen from green electricity, more than 95% of current production comes from 'reforming' of methane, and so as of today, FCEVs are not green. Worse still, there is a strong lobby from the oil companies to keep using petrochemicals as feedstocks for hydrogen. Understandably they want to keep using their reserves as we reduce our dependence on other liquid fuels. Until recently this lobbying has been at a low level, but since COP26 it is becoming more visible. I have seen Youtube ads, and recently the Sunday Times magazine carried a double page advert from Aramco advocating hydrogen related to this campaign:

https://www.aramco.com/en/campaigns/powered-by-how/blue-hydrogen

I can't see a solution where the green hydrogen would be economically viable against Hydrogen from the oil companies (due to the inefficiencies discussed above), and they have a second advantage- that they already own a distribution network that could be transitioned to supply of Hydrogen.

Thirdly there are unfair comparisons being made- if you compare Hydrogen against existing fuels (petrol/ diesel), as is commonly done, you get a very different picture to comparing against electricity

Up until now, I have illustrated the best case scenario for green Hydrogen- i.e. made with excess green electricity. Unfortunately we are not in a position of having significant excess green electricity supplies, we currently use it all in offsetting our generation by other fuels. It will be another 20 or more years before we truly do have excess green electricity that we could seriously consider using for Hydrogen production (generalisation!- We may see limited scale peak levelling schemes in a shorter timescale- that would be a whole other discussion)

https://gridwatch.co.uk/

There are also a number of technical challenges to also be addressed;

Storage and distribution

Storage of hydrogen and it's distribution is difficult. It can either be moved as a compressed gas, or as a liquid. Both have significant challenges. Hydrogen is a gas with a very low density, and so to compress it to usable levels requires a lot of energy, even when compressed heavily, it's density remains low. There are absorption methods that help increase the gas that can be stored in a cylinder, but even with implementing these we end up with sizeable storage tanks.

If we look at commercial cylinders, a 50 litre nominal cylinder only holds 1kg of gas!!!

https://specialty.airliquide.co.uk/product/hydrogen-5-0-501/?industry=oil-and-gas

Whilst a lot can be done to reduce this mass, it nevertheless remains a significant part of the vehicle mass, less than batteries but not insignificant like a petrol tank.

As a liquid, the fill density will be much higher, but then you have to maintain the temperature below -253C, put a lot of energy in to liquify, and live with constant losses with the gas boiling off (again detracting from efficiency). I'm not aware of any practical applications on vehicle using liquid fuel, so you would also have the complexity of converting from a liquid and back to gas at a fuelling station.

Technical Complexity

It's easy to think of just the fuel cell stack itself, which in reality is quite simple, but there is a lot of complexity around this;

Water management is needed to both stop the membranes fully drying out as they warm up, but also remove the generated excess water safely (without causing isolation issues when running at 100s volts).

Temperature needs control- freezing of the water would also be detrimental as would overheating.

Air is needed in large volumes, so powerful external blowers are needed. This comes with air management and filtration needed to avoid bringing in dust or particulate contamination.

A level of cell balancing and management is needed, similar to that used with Lithium ion cells.

Pipework and valves are needed for the H2 gas supply.

All of this needs careful control to balance the gas flow with the electrical load.

There are now well integrated solutions to much of this, but there is a level of complexity to these systems that is often not thought about.

Rare Metals

Whilst fuel cells do not use rare earth metals, the PEM type used in vehicles do however use platinum, another metal where supply is limited and expensive.

Life & poisoning

As fuel cells are reacting two chemicals together with aid of a catalyst, there are mechanisms for the catalyst to be 'poisoned'. The presence of a number of chemicals particularly Sulphur containing ones, such as Hydrogen Sulphide and Sulphur Dioxide as well as Carbon Monoxide and Sodium Chloride can reduce the effectiveness of the cell significantly, reducing it's life.

https://www.technology.matthey.com/article/57/4/259-271/

https://www.hydrogen.energy.gov/pdfs/progress05/vii_i_4_uribe.pdf

This means the hydrogen used must be very pure, but even with this in place there is a very real risk of atmospheric pollutants making their way into the cell mixed in with the feed air, and subsequently shortened lifetimes.

Other uses

In my opinion, the best uses for any hydrogen generated from electricity in schemes using excess electricity is in displacing fossil derived hydrogen as chemical feedstocks in industrial processes such as the manufacture of fertilisers. Whilst there would still be an efficiency hit in the electrolyser, we don't get the second hit when converted back to electricity. Secondly these processes need hydrogen, there is no other viable alternative, and so eliminating the use of methane would bring additional benefits- no carbon capture needed for example.

Much of what I have written has been summarised as a graphic known as the 'hydrogen ladder' which can be found at the first link above. This neatly ranks the uses of hydrogen from 'Unavoidable' there is a clear benefit (such as the chemical feedstocks above), down to where they are 'Uncompetitive'. Overall I think this is a well thought out and presented graphic, I'm sure there are some use that could change position a little, but I believe the overall ranking is sound.

[Superpants]

I've recently seen a couple of press releases that may be of interest. The first is a serious attempt at Lithium carbonate extraction in the UK, with a pilot plant running:

https://britishlithium.co.uk/first-lithium-carbonate-produced/

It's worth noting that the vast bulk of Lithium ion batteries don't use metallic Lithium, and compounds such as carbonates may be used directly.

 

Secondly Veolia, one of the biggest waste management/ recycling companies has announce the construction of a UK dismantling/ recycling plant:

https://www.veolia.co.uk/press-releases/veolia-announces-its-first-electric-vehicle-battery-recycling-plant-uk

[landroversforever]

Great post Superpants, good to have some more information on the subject for everyone. Jsut a couple of points from someone who uses Hydrogen on an almost daily basis (or at least we use the isotope Deuterium).

39 minutes ago, Superpants said:

Storage and distribution

Storage of hydrogen and it's distribution is difficult. It can either be moved as a compressed gas, or as a liquid. Both have significant challenges. Hydrogen is a gas with a very low density, and so to compress it to usable levels requires a lot of energy, even when compressed heavily, it's density remains low. There are absorption methods that help increase the gas that can be stored in a cylinder, but even with implementing these we end up with sizeable storage tanks.

If we look at commercial cylinders, a 50 litre nominal cylinder only holds 1kg of gas!!! Hydrogen is the lightest gas molecule so rather than it 'only' being 1kg of gas it should be the energy density that is compared. For example the MAST-U Spherical Tokamak fusion machine we run only drops one of those cylinders by ~5bar for a full day of operations.

https://specialty.airliquide.co.uk/product/hydrogen-5-0-501/?industry=oil-and-gas

Whilst a lot can be done to reduce this mass, it nevertheless remains a significant part of the vehicle mass, less than batteries but not insignificant like a petrol tank.

As a liquid, the fill density will be much higher, but then you have to maintain the temperature below -253C, put a lot of energy in to liquify, and live with constant losses with the gas boiling off (again detracting from efficiency). I'm not aware of any practical applications on vehicle using liquid fuel, so you would also have the complexity of converting from a liquid and back to gas at a fuelling station.

Getting the liquid back to a gas at the fueling station isn't really an issue as it would be just like any other cryogenic boil off. 

[Superpants]

Good points- I'll have to look out the energy density equivalents.

On the return to gas, you are right that getting it to a gas isn't the challenge, what I should have added there is that the gas would then need compressing to a level which it could be transferred to the vehicle- again adding complexity and another (energy efficiency) loss.

 

[Superpants]

For the equivalency:

1kg approx. equivalent to 2.8kg petrol (approximately 1 gallon)

https://afdc.energy.gov/fuels/hydrogen_basics.html

[jeremy996]

My worry for hydrogen is it is used by the petrochemical industry as a Trojan Horse for dubious "Greenwashing"; I can see a use case for intensive operations, say heavy plant or an off-road vehicle but I'd have thought that conventional green fuels like biodiesel, ethanol or methanol would be less hassle overall, especially if there was no hydrogen on site.

(Ineos's use of hydrogen for the Grenadier prototype smacks of significant self-interest, as it is one of the biggest H2 suppliers in the world).

Margaret Thatcher was the first and last Prime Minister with a science degree; politicians as a group are terrible judges of viable technologies.

[elbekko]

Couple of thoughts on that post (and yes, I am a big proponent of hydrogen fuel cell vehicles):

• It doesn't have to come from fossil fuels. Just like electricity can be cheaply produced from fossil fuels, doesn't mean that's always going to be the case, so I'd say that's a pretty disingenuous argument.
• Generation inefficiency really doesn't matter because it's easily transportable. Nobody says you have to use local (excess or not) power. There are vast swathes of the earth with lots of water and nearly free power: solar, wind, geothermal. Line transmission makes these nonviable to connect to the grid, but hydrogen you can just chuck on a boat.
• All the downsides you list for fuel cells, except for the purity of the hydrogen, are valid for BEVs too. Lithium-Ion batteries need a bunch of thermal management, both heating and cooling.

You also handily didn't list the upsides of hydrogen fuel cell vehicles:

• Weight. Weight is a huge factor in efficiency, and being able to avoid having a 1 tonne battery is big.
• There is already a bunch of hydrogen infrastructure around. Pipelines already run across Belgium, and I wouldn't be surprised if that's already the case in other countries too:
• Refuelling time remains a big one. Charging a huge battery quickly is just limited by the laws of physics. Charging a 150 kWh battery in 5 minutes with a 600V charger would take 3000A continuous (!). Even at 10kV that's still 180A. Totally ignoring here the massive amount of heat the battery would need to dissipate while charging.

[geoffbeaumont]

1 hour ago, elbekko said:

It doesn't have to come from fossil fuels. Just like electricity can be cheaply produced from fossil fuels, doesn't mean that's always going to be the case, so I'd say that's a pretty disingenuous argument.

To be fair, @Superpants didn't say that was a problem with the technology itself. He said there's a lot of powerful interests pushing hydrogen generation from ecologically unsound methods that make them money, and presenting it as "green". Greenwashing isn't a new problem - it's going on with electricity generation too - and it isn't an argument against the technology per se, but it is something to be aware of when weighing arguments. E.g. Does this only make economic sense if you use costs from production methods that aren't really solving the problem?

[Superpants]

8 hours ago, elbekko said:

Answers to the points below:

Couple of thoughts on that post (and yes, I am a big proponent of hydrogen fuel cell vehicles):

• It doesn't have to come from fossil fuels. Just like electricity can be cheaply produced from fossil fuels, doesn't mean that's always going to be the case, so I'd say that's a pretty disingenuous argument.

  • I agree that Hydrogen does not have to be extracted from fossil fuels, there are technically viable alternatives, however as it stands today the vast majority is extracted from them and therefore right now battery electric vehicles are considerably greener, (having a lower carbon footprint). If left purely to the free market, I cannot see how we would increase the proportion of green hydrogen as we have a combination of vested interests (oil companies) and higher costs for the green production. The only way I can see the proportion of green hydrogen increasing significantly is If our governments were to work together and bring in legislation to require it, or there were overwhelmingly beneficial incentives (noting that this has been what kick-started the big solar and wind power schemes).

  •  

• Generation inefficiency really doesn't matter because it's easily transportable. Nobody says you have to use local (excess or not) power. There are vast swathes of the earth with lots of water and nearly free power: solar, wind, geothermal. Line transmission makes these nonviable to connect to the grid, but hydrogen you can just chuck on a boat.

  •  I agree that in areas where green electricity production is easier and there is not local demand for the electricity (North Africa for instance), Hydrogen production could be a way of storing and transporting that energy. Bear in mind that the volumetric energy density is significantly lower than that for liquid fuels and therefore to move the same amount of energy, larger tanker volumes would be needed for Hydrogen. The efficiency of the conversion is still important though as it would translate to the installation cost of the project.

    I believe that the best use for this hydrogen is to offset that used in the chemical industry (fertiliser production etc) as this would offset the need for the use of hydrogen obtain from fossil fuels where it is essential to use hydrogen for its chemical properties.

• All the downsides you list for fuel cells, except for the purity of the hydrogen, are valid for BEVs too. Lithium-Ion batteries need a bunch of thermal management, both heating and cooling.

  • It’s true that batteries need thermal management, and therefore the battery used in a FCEV will also need this. What a fuel cell brings is additional ‘Balance of Plant’. This is not a technical barrier in any way, however it is very easy to miss the complexity of a fuel cell system if you only focus on the fuel cell stack.

You also handily didn't list the upsides of hydrogen fuel cell vehicles:

• Weight. Weight is a huge factor in efficiency, and being able to avoid having a 1 tonne battery is big.

  • See notes under last point

• There is already a bunch of hydrogen infrastructure around. Pipelines already run across Belgium, and I wouldn't be surprised if that's already the case in other countries too:

  • I didn’t mention infrastructure particularly as I believe it is ‘swings and roundabouts’ when you compare it with electricity infrastructure. I don’t see there being many major technical challenges in the Hydrogen infrastructure, as illustrated by your example of existing pipelines. BEVs will need grid, and especially local distribution upgrades, but this can mostly be staggered over time. This is likely to be a more distributed task though. Hydrogen infrastructure arguably needs bigger up-front investment (pipelines can’t easily be built piecemeal). Either way we will have some technical challenges and some big investments to be made.

• Refuelling time remains a big one. Charging a huge battery quickly is just limited by the laws of physics. Charging a 150 kWh battery in 5 minutes with a 600V charger would take 3000A continuous (!). Even at 10kV that's still 180A. Totally ignoring here the massive amount of heat the battery would need to dissipate while charging.

  • In the US (I have never found directly equivalent UK figures, but our mean mileage is less), 97% of travel (by road) is below 150 miles per day (when vehicle is in use). For BEVs, it is expected that the vast majority of charging will be carried out at home, typically overnight and so the refuelling time is not as big an issue as you would first expect. There will need to be fast chargers on the motorway and trunk road network to service those vehicles that genuinely do need to do high mileage, but again whilst this will need investment, either FCEV or BEV would need similar numbers of service station upgrades.

    On the weight point, if the mileage needed isn’t that high, then batteries don’t need to be heavy- the vast majority for passenger cars won’t be anything like 1 tonne, more like the 3-400kgof a leaf. At this, the weight saving advantage starts falling away (struggling to find mass of FCEV parts), but it is still there.

    This leaves some special applications where Hydrogen does make more sense because of the refuelling time or convieniece- very long distance vehicles, vehicles operating away from practical charging infrastructure (military/ agriculture) or ones where the machine does not sit idle overnight (mining etc).