[reppy]

I think this link holds the key to unlock the future use of hydrogen safely - the main concern has always been safety of the fuel.

Edit: this video is more detailed for the nerds out there

https://youtu.be/yVGbPf43DeM

[sentra26]

Originally Posted by reppy

the main concern has always been safety of the fuel.
https://Youtu.be/yVGbPf43DeM

Being flammable should not be a problem for hydrogen fuel cells. Infact, hydrogen dissipates rapidly into the atmosphere. Hydrogen theoretically in that quantity and under that pressure should safer than gasoline.

[DicKy]

Without getting technical and just from my superficial knowledge.

Today's petrol applications = Battery EVs

Today's diesel applications = Fuel Cell (hydrogen) EVs

Sooner or later this juggernaut of 'BEVs will save the earth from catastrophe' trope will stop, and better sense will prevail among authorities regarding alternatives for transportation energy.

Only problem is that for hydrogen to be widely adopted, governments and companies should encourage more filling stations. Unlike BEVs which could be charged anywhere.

[whitewing]

As far as I recollect among the passenger car manufacturers only Toyota has invested in fuel cell tech and it has even rolled out a commercially available model since 2014. Why someone would buy them given the limited options of recharging is another open question.

Originally Posted by sentra26

Being flammable should not be a problem for hydrogen fuel cells. Infact, hydrogen dissipates rapidly into the atmosphere. Hydrogen theoretically in that quantity and under that pressure should safer than gasoline.

The gas needs to be stored at at much higher pressure than CNG.The brochure for the toyota car Mirai mentions that the pressure is at 700Bar i.e almost 10kPSI ! Which is several times over that of than CNG.

[carthick1000]

A normal combustion engined passenger car is somewhere around 30-35% efficient in converting fuel to usable power. If well to wheel is included, then the efficiency drops even further due to energy losses in fuel extraction and refineries. If conservatively taken, an ICE car is about 20% efficient.

Whereas a Hydrogen fuel cell electric car is a bit better than a combustion engined car at about 25-35% for well-to-wheel and a battery electric car comes the best in terms of efficiency of converting fuel to usable power at around 80%. This also depends on how the electricity is produced. The more renewable energy used to produce / extract / refine fuel, every type of powertrain can benefit from it. Inherently, a battery EV has the most potential to be efficient for passenger cars. Recently, a Dutch utility company made a comparison of well-to-wheel between Hydrogen FCEV and BEV (Passenger cars) and here is an overview from their presentation.



I think FCEVs cannot bring much more on the table than ICE passenger cars, but only BEVs can. However, in the commercial sector (Buses and Trucks) which has a longer lifespan and extremely high usage cycles can benefit from hydrogen. However, not from fuel cell technology, but from converting existing IC engined trucks and buses to combust hydrogen. This is predominantly for emissions regulations rather than efficiency improvements. I think AVL Austria is working on such a technology. For those who would like to go more in detail on this topic, AVL offers a mobex webinar. You just have to register and then can watch it here: https://www.avl.com/-/co2-reduction-...ydrogen-engine. It takes only a minute or two to register and the webinar is about 1 hour, but very technical and interesting.

Fuel cell hydrogen cars like Toyota's Mirai and Hyundai's Nexo are very rare even in a country like the Netherlands, which has the best BEV charging infrastructure in the world. So FCEV passenger cars going mainstream in competition to ICE cars and BEVs is a taller order, imho.

Here is a very nice video made by Fully Charged show on the comparison between ICE and EVs. This gives also more perspectives on the whole energy chain, in terms of efficiency and emissions.

https://www.youtube.com/watch?v=mk-LnUYEXuM

[SKC-auto]

Green Hydrogen may be for a small % of trucks and buses. I envision a future, where there is plenty of cheap solar power, Green Hydrogen made from excess solar power. I am not sure if this is really viable when battery tech becomes very cheap for grid storage.

Originally Posted by carthick1000

However, not from fuel cell technology, but from converting existing IC engined trucks and buses to combust hydrogen.

My understanding is, you cannot convert an ICE engine to H2 engine without major changes to the engine. Also, burning hydrogen is not clean, it emits NOx just like any high temperature burning.

https://youtu.be/1Ajq46qHp0c

[carthick1000]

Originally Posted by SKC-auto

My understanding is, you cannot convert an ICE engine to H2 engine without major changes to the engine. Also, burning hydrogen is not clean, it emits NOx just like any high temperature burning.

Your understanding is correct. It is not retrofitting a Diesel or natural gas engine (also small % of EU commercial vehicles) with Hydrogen combustion, but replacing just the Diesel/Natural gas engine with Hydrogen engine and the hydrogen supply system. The rest of the components can be more or less the same as current ICE engines. Note that the main reason is to bring the time to market less/quick (AVL talks about a phased approach starting from end of 2021 until maturity of technology in 2030) and to bring the TCO down. We all know how people complain about EVs of the same class of cars being too expensive. So TCO is a major factor not only for fleet owners but also OEMs to keep most part of powertrain/chassis the same except for the engine. This alleviates the issues we have with passenger cars where some OEMs don't want to go with clean slate-ground up designs, because they have heavily invested in the infrastructure and facilities. With fuel cell, the costs go up quite a lot as the powertrain is much different and increases time to market.

Burning hydrogen is not clean as a fuel cell, but much cleaner than Diesel/natural gas, as zero CO2 can be achieved. This also requires that the Hydorgen is sourced energy neutrally. Also in AVLs presentation, they mentioned that their test rigs have zero NOx emissions during full load and part load conditions and very minimal NOx at transients. Of course this test rig used also the same/similar current gen NOx after treatment systems used in Diesel engines.

Attaching an overview slide from the webinar :

[srini1785]

As some members have pointed out, its rather cumbersome to design a IC engine (Piston, valves et all ) for using hydrogen as a fuel. Not only do you need to work out the metallurgical aspects of the valves, pistons, rings etc, you also need to consider how to store hydrogen. Hydrogen combustion also requires a catalyst like Paladium or Platinum. So my vote would always go to using hydrogen to power fuel cell and to use the electrical energy to power a motor. Much easier that way.

[SKC-auto]

VW group CEO Herbert Diess criticizes hydrogen debates. Interesting times to watch world's two largest automobile companies, one believes EVs are the future, the other believes HFCV as the future.

[electric_eel]

https://youtu.be/JlOCS95Jvjc

TL;DR

1. Hydrogen as a fuel makes no sense and is mostly promoted by guess who ?
2. The only place where hydrogen makes sense is when it is use as a Chemical and
not as a fuel (eg in Habers process for creating amonia)


A side remark "for the EVs have more emission due to the Li extraction"

The total amount of fugitive carbon foot print due to the escaping methane is something like the total carbon foot print of Europe.

The methane is supposed to be the "waste" in the extraction of oil and needs to be gotten rid of by burning it to reduce it to the lesser evil (CO2). The fugitive methane is the methane that escapes from the burning process.

[volkman10]

Germany now says it can't depend on BEVs alone, measures to promote hydrogen and e-fuel cars drafted.

A bill to exempt e-fuels cars from Value Added Tax (similar to our former GST) is being drafted and will be tabled before the year ends.

We are not alone in observing that electromobility still leaves too many questions unanswered - from affordability to the availability of lithium for the batteries to the charging infrastructure. As long as these questions remain open, we should also look at other alternatives. We want to send a clear signal: We need e-fuels, including in road transport – if only for the millions of existing vehicles

Link

[ferrarirules]

Originally Posted by volkman10

Germany now says it can't depend on BEVs alone, measures to promote hydrogen and e-fuel cars drafted.

No single technology can be the answer as a replacement for IC engines. So their choice to promote e-Fuel and Hydrogen is not a wrong choice. But there are their own challenges for the alternate options and the same is highlighted in the article itself

e-Fuels challenges/drawbacks

Critics, say that e-fuel is just a futile measure to delay the inevitable demise of Germany’s internal combustion engines-heavy automotive industry. They say that e-fuel is too expensive to produce and combustion engines, regardless of their fuel, can never be as energy efficient as electric motors.

Hydrogen challenges/drawbacks

Like e-fuels, critics say hydrogen is too expensive for widespread use, and majority of hydrogen supply is still being produced via carbon-emitting industrial methods. Look around you, obviously it is easier to find a power plug than a hydrogen tank.

Finally according to them the best way to reduce carbon emissions is to reduce reliance of private vehicles

Apart from cars, Germany’s is working to reduce its reliance on private cars, which regardless of energy source, will still not be as green as trains.
An 10-year, 86 billion Euros investment to improve Germany's rail infrastructure, especially with regards to punctuality of long-distance high-speed trains along the very car-heavy Mannheim and Frankfurt route, is now underway.