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Mercedes-Benz eyeing introducing a sedan model hydrogen fuel cell vehicle around MY 2017

The 2011 F-Cell. Click to enlarge.

Mercedes-Benz, which has begun leasing of the limited production B-Class F-Cell hydrogen fuel cell vehicle (earlier post) in California, is on track to roll out a MY 2015 next-generation B-Class F-Cell in much larger quantities for sale, and is considering introducing a regular sedan-class fuel cell vehicle in around MY 2017, Sascha Simon, Head of Advanced Product Planning at Mercedes-Benz USA, said in an interview with Green Car Congress—perhaps an E-Class version, he suggested.

We are not intending to build a particular fuel cell sub-brand that looks and feels different. Our customers would like to drive our E-Class as a fuel-cell car. It [fuel cell technology] would work beautifully in a regular sedan shape—normal Mercedes luxury, but filled with pressurized hydrogen. I am completely convinced the technology has the potential to take over the internal combustion engine, together with pure battery EVs in their niche.

—Sascha Simon

Currently, Mercedes-Benz has 37 leasing customers for the B-Class F-Cell in Southern California, with suggested pricing set at $849 per month for 24 months. Several hydrogen fueling stations are now open in Los Angeles and surrounding areas, including Newport Beach. The F-Cell will become available for Northern California in June.

Although Mercedes-Benz has introduced a plug-in hydrogen fuel cell research vehicle—the F125! (earlier post)—which projects out about 20 years, Simon suggests that a pure fuel cell vehicle could be more price-efficient than a plug-in.

For me it comes down to the price point for batteries versus fuel cells stacks and how this plays out. If you obviously have a price premium for batteries that is not going down over the next ten years, I would argue that a pure fuel cell vehicle is more price efficient versus a plug-in. If you look to the plug-in world right now, the current numbers don’t bode so well. We haven’t see a drop in prices in batteries that we would like to see; we’re monitoring the price point and we’ll take it from there.

I do believe that it is as easy to build a fuel cell car as an ICE [internal combustion engine] car today—and we are almost there—without the need for plug-in capacity. This car [the B-Class F-Cell] is ready for mass production. It drives like a normal car. The HMI is built like a normal car. It’s not not science fiction, not a prototype. They are real-world cars on lease.

—Sascha Simon

“Really now the biggest topic is the available infrastructure. That is really the only hold up there is—there is no other reason why we are not rolling out more of these cars. The new legislation [the Advanced Clean Cars package in California, earlier post] will help very much.”
—Sascha Simon

B-Class F-Cell. The front-wheel drive B-Class F-CELL offers an operating range of around 240 miles (386 km) on the European driving cycle, or 190 miles (306 km) estimated EPA, and a 3-minute refueling time.

The technical basis for the drive system of the B-Class F-CELL is a second-generation fuel cell stack from Automotive Fuel Cell Cooperation (AFCC)—a Canada-based joint-venture private company between Daimler AG (50.1%), Ford Motor Company (30%) and Ballard Power Systems (19.9% ownership and a financial investor). AFCC serves as a fuel cell center of excellence for the two OEMs. The second-generation stack in the B-Class F-Cell features a power increase from 65 kW to 100 kW, increased lifetime and reliability, and freeze start ability below 0°C.

(In March 2011, Mercedes-Benz announced that it would set up its own production of fuel cell stacks in Vancouver, British Columbia—home of AFCC. Construction of the plant is underway, Simon noted.)

The B-Class F-Cell also features a 1.4 kWh Li-ion battery pack and a compressed hydrogen storage capacity of 3.7 kg at 700 bar. The 136 hp (101 kW) electric motor develops 214 lb-ft (290 N·m) of torque; the B-Class F-CELL uses a single-speed gear reduction transmission w/reverse and recuperation.

The vehicle accelerates from 0-60 mph in 11.4 seconds, and has a top speed of 106 mph (171 km/h). Estimated fuel economy is 52 miles/kg of hydrogen on the city cycle, 53 miles per kg on the highway.

Progress in fuel cell power density. Source: AFCC 2009. Click to enlarge.

Next-generation fuel cell work: costs. Overall, Gen 3 fuel cell cars—e.g., the next-gen MY 2015 F-Cell—will demonstrate capabilities competitive with other platforms, but cost remains an issue, according to an AFCC research needs analysis presented in 2009. Accordingly, Generation 3 fuel cell stacks will focus on cost reduction. The Gen 4 stack—which would appear in the sedan application—will also focus on further cost reductions.

There are five basic strategies for cost reduction, AFCC says:

  • Less expensive components for balance of plan (BOP);
  • Fewer components;
  • Less parasitic power loss;
  • Less material in the stack itself; and
  • Less expensive material in the stack.
Platinum content reduction and power density. Source: AFCC 2011. Click to enlarge.

Given the high cost of platinum, new durable, high-activity (and lower-cost) catalysts are critical, AFCC says. Current mature technologies—such as carbon-supported Pt catalysts, current membranes, and current cell and plate designs—have reached their maximum capability, and the Gen 4 stack will utilize them at their maximum. Alternative paths or breakthroughs are needed.

Possible new pathways for cathode catalysts include stabilized platinum alloys; new catalyst-support (non-carbon) interaction (e.g., high surface area metal oxides or core-shell catalysts); pseudo bulk catalysts; and non-precious metal catalysts.

Possible new pathways for membranes include low-cost PFSA membranes; hydrocarbon membranes; or additive technologies—i.e., improving membranes by adding special functional materials.





'Because I post a reference does not mean that I agree with every word of the source."

But you also said:

"The persistent negativity of those who want batteries and nothing else, and were claiming fuel cell cars would always cost $1 million and so on, is being knocked down peice by peice...."

You were pretty confident those sources dealt a real blow, but now you aren't so sure anymore?

"I am surprised that you sould find my concerns at the problem of wiring up for road side charging unfounded, as I would imagine in Holland just as in the UK there is simply nowhere to put them in many locations, and they are aso confronted with the problems of urban vandalism etc quite apart from hazards caused by the cords."

I am not sure why road side charging should not be possible on 90% of the current parking spaces. We have 30+ years to deal with the remaining 10%. Everything suffers vandalism. Cars get scratched, bus stops destroyed. Does that prevent people from buying a car? Did we abandon public transport?

There are quite a few public charge points in Amsterdam right now for the Car2go system. As of yet I have to see any reports of vandalism, so that concern can be quickly dealt with I suppose.

And what hazards exactly do these cords pose?

I am surprised that you blow up these minor (or worse: imaginary) concerns into roadblocks to the adoption of EV's.

"but it still provides power for things batteries can't cover, heavy transport..."

As a regular reader of this blog, you should know better.

...long distance rapid travel

What happened to fast charging? The current state of technology is not definitive. Improvements will be made. Faster charging batteries (like the Toshiba SCiB that is already here) and more powerful chargers. Give me one good reason why we won't have 500 kW fast chargers in the future that can charge a 80 kWh battery in about 10 minutes. That's a 10 minute break every 300 km. Seems a rather normal pattern on long road trips. And real fast long distance transport is done by highspeed train or plane, not the car.

"places where charging is not available."

The grid is almost everywhere you want to go with a vehicle. Now you're talking about a niche in a niche. That's exactly how it's going to be: EV's for 90% the rest uses biofuels and/or hydrogen.

I am not against hydrogen or anything but as things currently stand, I can not see a future for it as mainstream technology. As I have said more often, either you base the system on a non-renewable source (natural gas) or the overall efficiency (call it wind-to-wheel if you like) is about half that of the BEV. Some real progress has to be made in that area.


'You were pretty confident those sources dealt a real blow, but now you aren't so sure anymore?'

I made it very clear that this is based on the figures for hydrogen infrastructure, which were not previously available and opponents claimed would cost in the trillions.
Here is a comment on setting up a skeleton infrastructure in Germany:

Costs are simply not in the stratospheric levels claimed.

I am not sure why many choose to assume the most fantastic increases in battery capacity, and reductions in cost, but see not progress as being possible in fuel cells.
The 80kwh battery you envisage would at the moment weigh about 800kg at the cell level, as the SCib chemistry is low energy density at about 100wh/kg, and Toshiba's ressearch is only for up to 150wh/kg.

In addition at something like $200kwh you start running into materials cost limits on batteries, so getting below that would be difficult, although I do not say it is impossible.
That is $16,000 on top of the price of the car.

A plug in fuel cell hybrid might need around 12 kwh of batteries, 30kw of fuel cell plus of course $3,000 for the CF tank.
That is maybe $1200 for the batteries, perhaps $2000 for the fuel cell, and $3,000 for the tank.

I am not against using batteries where possible, but they aren't going to be running trucks anytime in the foreseable future, and long range and heavy loads are well within the capabilities of fuel cells, but not batteries.

As for the pavements and street furniture, that would be fine with induction charging, which is also vandal proof, and a real mess with cords.

"Costs are simply not in the stratospheric levels claimed."

Which still doesn't address my main concern which is that with a FCV you face a choice of either fossil fuel dependence or low overall efficiency. To fix that, you'll have to bet on future technological progress. Just as much or even more perhaps as advances in battery technology.

"I am not sure why many choose to assume the most fantastic increases in battery capacity, and reductions in cost"

People expressed the same opinion 5 years ago. Yet here we are in 2012 and the progress in energy density and decline in price did happen nevertheless. My assumption is based on extrapolation of that trend. The amount of R&D money poured into battery research is multiple times that of a few years ago. It would be very weird if that didn't yield any results.

The looming overcapacity in battery manufacturing will guarantee a downward pressure on battery price. Admittedly, some lithium chemistries contain expensive materials like cobalt or nickel, but the more promising chemistries (LiS or Li silicon for example) do not.

Also, I'm not envisioning those cheap, light, fast charging 80 kWh batteries for 2015. Not even before 2020. Looking at the history if NiMH, in 2002 that was already a mature technology and I bought 4 state of the art 1800 mAh Duracell penlights for my digicam. Today 2500 mAh is more like the standard. Or, if you like, 2000 mAh without self-discharge. Simply optimizing currently available chemistries can yield significant results.

When you say "...for things that batteries can't cover...", I am inclined to believe that you mean the battery will never be good enough. I'm trying to argue that in your concerns I did not find any fundamental reason why EV's can not serve the majority of our road transport needs. Progress is still needed, but the same is true for H2 vehicles.

Overall, I judge the breakthroughs needed for the creation and storage of hydrogen more challenging than those for battery technology. But that is a subjective observation that I can not numerically support.


I simply do not know how far and fast battery costs will drop.
I am perfectly happy to use batteries for whatever they can do.
That very progress though reduces the grounds for your concern about the relative assumed inefficiency of fuel cells via hydrogen, although in fact that is a rather artificial objection, as reforming NG for hydrogen ahd using it in the present grid, as opposed to a more efficient grid more based on combined cycle and so on, is in the same ball park as the grid and batteries for the US if not for Holland.

For the future there are a pile of assumptions needed to say that the hydrogen economy is relatively inefficient, as it is all projections of technology.
If the production of hydrogen is partly done by using surplus wind, for instance, which would otherwise be wasted, how does that affect the supposed inefficiency?

Mainly though, the better the batteries, the easier it will be to support fuel cells, so that short journeys are done using the battery at high efficiency, and a fuel cell RE using hydrogen only kicks in for distance, so avoiding the need for a massive battery.

It really boils down, like a lot of practical engineering, to boxing clever, and using and combining avialable technolgies for what they can do, and using them to minimise and overcome each other's weaknesses.

I think fuel cells have a part to play, as well as batteries, but welcome all progress in both.

Roger Pham

If we are going toward non-fossil-fuel economy, then we will need some sort of synthetic fuel for all sorts of local use. Of all potential forms of synthetic fuels, H2 so far was calculated to be the least costly to synthesized and the least inefficient energy-wise to produce. The scientists at all major national laboratories and manufacturers have looked at all these, and have not come up with anything better than H2.

As long as H2 infrastructure is going to be built to serve most of our energy needs, then it follows that some future cars and trucks will run on H2. The building of H2 infrastructures will not be just for transportation, but also for home and industrial uses as well. As such, the proportion of the cost of H2 infrastructure dedicated for H2-V will be small and will be easily supported by the consumers.

So, if one is still inclined to think that H2 is an inefficient energy carrier of renewable energy, please kindly remember that it the least inefficient synthetic fuel of all potential candidates so far!
But please feel free to research for better synthetic fuels than H2 and advise us.



I've just been through your big reference paper and what it references for truly renewable H2 sources are things like microbial electrolysis cells (electrically assisted anaerobic decomposition) and electrolysis using e.g. PV electricity.

These resources are either very limited, very expensive or both.  This report is effectively a stealth attack on non-fossil energy; any non-carbon supply is not going to be competitive against reformed NG or gasified coal because of the chosen medium.  If the selected medium is electricity, the advantage shifts the other way.

The other factor is that most reports assume current US market conditions will continue indefinitely.  This NETL paper bases its analysis on $2.85/mmBTU.  World prices are in the region of $15/mmBTU, and a few large LNG export terminals in North America are all it will take to quintuple the price here in the USA.  That takes the price of H2 up to the region of $4/kg, given that other costs track the energy cost implicit in construction.

Hydrogen FC is a dead end if any of this is true, and it appears that it is.  CNG FC PHEV is more efficient overall and has zero overhead for H2 infrastructure even when running on NG.


Hydrogen at $4/kg is by no means a dead end, but works jsut fine.
Even at present levels of fuel cell efficiency the Hyundau small SUV gets 72mpge.
IOW the greater efficiency of fuel cells makes up for the cost, and as I have argued motoring can continue for at worst present cost levels.

Actually though where I differ from the analyses I linked it that I see a future for batteries, and the use of a modest battery pack means that most miles would be done with batteries, and the cost of the hydrogen infrastructure would be reduced.

If you wanted to drive longer distances, the silent fuel cells kick in, and you carry right on driving on electricity.

Heavy and long distance traffic is easily catered for in this way, and you can't do that with batteries alone.


The argument you're making for hydrogen applies as much or more to methane-fuelled SOFC or MCFC sustainers, and a tank of CH4 carries several times the energy of a tank of H2.  This avoids the cost and commmitment of hydrogen infrastructure; like batteries, it can be done piecemeal.

Why aren't we seeing this?  Because all the government money is pushing hydrogen.  The game is rigged; anything we can actually do to replace oil is "not good enough", just like PHEVs weren't good enough for CARB in the 90's.

Siemens wants to wire highways to power trucks, which displaces both hydrogen and LNG.  I don't think hydrogen is going anywhere, seriously.  It's a diversion.


"I don't think hydrogen is going anywhere, seriously. It's a diversion."

Diversion IS the thirty year track record and purpose of historical purpose of H2 fuel cell vehicles to date.


I appreciate the optimism Dave, but a range extending H2FCV seems even less useful that a pure H2FCV. You are proposing adding a new fuel, storage system, production, distribution etc to supply a smaller amount of total miles driven.

I see long distance trucking using natural gas / diesel dual fuel and personal transport switching to hybrids with varying plug in ranges depending on personal requirements

We may well end up wtih SOFC's in transport but they will probably be running on diesel so no need to generate or store hydrogen.

Fuel cells are good, hydrogen storage / production is a bit of distraction IMO

Dim X as Date
X = Year(Now)
PRINT "Hydrogen fuell cell vehicles will be available in year" + (X+5)


I haven't got a hang up about hydrogen or anything else.
I'd love methonol fuel cells/really cheap fast cahrging batteries etc.
The point is that what we know at the moment is that we can do batteries with hydrogen fc REs and have the flexibility and capacity of ICE vehicles at affordable costs and good enough efficiency.

You are discounting the degree to which the deployment of hydrogen together with charging for batteries decreases the expenditure for both.

A basic, main route deployment of hydrogen means maybe 1/10 the infratstructure of putting the infrastructure in for a 1:1 replacement of petrol.

Putting in charging points for batteries where convenient, to those who have garages available and don't have to charge by the road decreases the cost of that deployment, and more imptantly not having to carry around hundreds of kilos of weight and cost of batteries as long range is covered by hydrogen enormously decreases costs.

The whole of batteries working with fuel cells greatly exceeds the sum of the parts.

The point is that what we know at the moment is that we can do batteries with hydrogen fc REs and have the flexibility and capacity of ICE vehicles at affordable costs and good enough efficiency.
And we can do batteries with methane or alcohol SOFC/MCFCs at a much more affordable cost.  Why hydrogen?  What does it get us?
A basic, main route deployment of hydrogen means maybe 1/10 the infratstructure of putting the infrastructure in for a 1:1 replacement of petrol.
The deployment of LNG on main routes is already started.  A tank of CNG or LNG stores a lot more energy than the same volume and weight of H2.  What does hydrogen get us?

Hydrogen is touted as being "renewable", but all the paths to renewable H2 thus far are much more expensive and less efficient than fossil sources.  This gives the perpetual advantage to fossil fuels, when electric power is agnostic.  Why not just use NG directly while this gets sorted out?  After all, the SOFCs that burn methane will burn H2.


The fact is h2 isnt likely to rise high enough to make it a worse deal then diesel or gasoline.

The fact is the factories have already been built the people hired the supplies contracted. No matter what somewhere around 150-250k h2 cars will be built in the next 8 or so years because effectively they haver already been paid for.

Most of the h2 infrastructure is being built and paid for by companies that already use h2 right now and need/want more of it. h2 cars will for the most part get a free ride on that end and only need pay for the stations and the last legs of system that get the h2 to those stations.. and its not as if they need all that many stations.

Most of the fuel cell tech is being paid for by companies that need then for things that have NOTHING to do with cars... so realy its just a matter of time always was. The other uses will progress the tech till its used in cars and trucks its simple as that.

H2 storage tech progresses because companies need to store h2 no matter is a single h2 car ever exists.. so again sooner or later fuel tanks great for car use will pop up or already exist.

As for battery tech... when I see many car makers and battery makers worried about short abnd mid term battery improvements.. that worries ME. Its not so much that I care about the car angle as I dont realy think we need much better bevs for at least 5-10 more years.. its that I want better gizmos and thingies that use the dang batteries BEFORE cars use em.. That is the stuff I love... and bad news for batteries means bad news for my TOYS.. and thats BAD!!!!!!!!!!!!!


By the time hydrogen and FCs readily available at an affordable price, very high energy density quick charge batteries will also be available at very affordable price.

The choice between the two technologies may come from the type of vehicle. Cars owners may pick EVs and larger trailer trucks and buses operators may pick FCs.

Having a choice may have advantages?

Roger Pham

Thank you, wintermane 2000, for discussing the expanding role of H2 in the energy future when GHG's will be phased out, just as CFC has already been phased out today and HFC and coal-fired power plants are under plan to be phased out.

Plus, the upcoming NG infrastructure for transportation (to take advantage of cheap NG) can be built to be H2-compatible so as to allow a near-cost-free transition to H2 further into the future. So, future H2-V's may practically hitch a free-ride, infrastructure-wise, if you would pardon the pun.

The choice between BEV and H2-V will be quite simple: people living in warmer climates will prefer BEV's for the higher efficiency when charged directly from renewable electricity. Colder-climate-dwellers will prefer H2-V due to the higher energy storage potential and having enough free waste heat in the winters for windshield defrosting and cabin heating. FCV's will have higher efficiency in winters than BEV's.


'The argument you're making for hydrogen applies as much or more to methane-fuelled SOFC or MCFC sustainers,'

Plenty of research is going on into both, but they are more difficult than hydrogen PEM's.
Not only are you doing in-vehicle reforming, but for SOFC's the temperature is very high, although work is under way on lower temperature versions.

Really, that is the point, I don't pick winners, just look at what are the best combinations and strengths of whatever we have to hand.
If we can mangage to use methanol instead of hydrogen then since it is much easier to handle, fine.
I just don't count my chickens.

As for why not natural gas instead of hydrogen,it is because you still have a combustion engine car, just one carrying a large high pressure tank, whereas witha fuel cell you are all electric and combinations with batteries are far, far easier, so the overall efficiency goes up.

Fuel cell RE's do introduce other components, mainly the CF tanks and humidifier, but you save having most of the batteries and avoid the issue of recharging time.

Electric roads if the basic technology works would be a far superior solution to most transport than using hydrogen, save perhaps for some heavy transport, and I am all in favour if it can be made to work.

Indeed I am engaged in an extensive and at times somewhat heated discussion over at ABG with those seeking to dismiss it out of hand, as it offends their alleged 'common sense', much as the Wright brothers must have done in their day when heavier than air flight was deemed by many to be an impossibility not worthy of consideration.

Basically I like batteries for everyday commutiing, but they are far from ideal for longer distances, and I don't think we have to learn to live with their limitations.

Providing batteries are used for commuting, the efficiency of the rest of the system is far less important even disregarding possible or probable improvements.


I should have added that the highway electrification I am interested in is not Siemen's rather peculiar overhead wire system, but inductive charging for all vehicles from sub-roadway plates being developed by Oak Ridge amongst others:

'In the Oak Ridge model, 200 coils would be embedded in a section of the roadway and controlled by a single roadside device; successive coils would be energized as electric vehicles pass over them, providing enough power for the vehicle to reach the next series of coils a mile down the road.

John Miller, a research scientist at Oak Ridge, estimates that each series of coils plus the controller would cost less than a million dollars. "Wireless chargers for electric vehicles are so convenient. You don't have to mess with plug cables. You don't care what the weather is. You don't even have to think about it. I think it's going to catch on superfast," Miller says.'

If, and it's a big if, this can be made to work it hammers everything else, and cars would only need a small 12kwh or so battery for local running around and to reduce the installation of electric roads to the main routes making the costs work.

I've run the figures and both from a cost and a power draw POV with battery backup to spread the load on the ground instead of in the car the economics are fine.

They now estimate $800,000 per mile per lane, down from the $1 million in the link.

It boiilws down to it being a lot more effcient not to lug anymore batteries around in the car than you have to.

Roger Pham

Nice technology. Do you have the figures for the losses in the induction coils in the roadway and within the vehicles? Due to these losses, I am not so sure that this method would be "a lot more efficient [than] not to lug anymore batteries around in the car than you have to. Future batteries will be lighter and cheaper than today's batteries. A PHEV with a good size battery pack and a small engine or FC will do just fine and will give better energy security, especially in colder weather.

Most of the h2 infrastructure is being built and paid for by companies that already use h2 right now and need/want more of it.
And many are building it for their own value-added operations, not for merchant sales.  If they didn't have anything ready to use the hydrogen, they wouldn't produce it.  Some people are making the assumption that this will be available for sale as FCV fuel; this assumption is wrong.

It also continues to beg the question of what this H2 is going to come from (NG or electricity), and why not just use that instead?  A tank of CNG holds several times the energy of a tank of H2 at the same pressure, so why does the FC car need H2 instead of a reformer?  Several answers suggest themselves, none of them pointing towards legitimate motives on the part of those in charge of picking the direction of research.

As for why not natural gas instead of hydrogen,it is because you still have a combustion engine car
No, this would be an SOFC, PEM-with-reformer, or maybe MCFC car.  Still fuel-cell, just not hydrogen.  Why is everything aimed at hydrogen, when the source fuel (natural gas) could be used aboard the vehicle instead of after steam-reforming?

Just pointing out how this whole thing is about (a) picking winners, (b) demanding perfection because "good enough" threatens the status quo, or (c) both.

Roger Pham

Again, the answer as to why renewable-energy H2 and not NG has to do with grave climate concerns caused by escalation in GHG's levels, aka global warming and huge floods and hurricanes and droughts and rising sea level and acidification of the ocean...etc.

The issue is analogous to why CFC was phased out, eventhough it worked great and was cheap to produce and uses much lower pressures than the HFC that replaced it.

H2 from renewable energy will be very affordable in the future, based on current trend in technologies. Soon, there will be no justifiable reason why we should hold back H2 in solving the multitude of grave climate concerns.

And, let's not forget we are having a severe unemployment crises all around the world that is threatening economic stability and governmental stability. The solution for this is the development of renewable energy collectors and infrastructures.

the answer as to why renewable-energy H2 and not NG has to do with grave climate concerns caused by escalation in GHG's levels
But that begs the question, Roger:  why is storage of H2 the "solution" to this?

If we're looking to store energy in chemical form, hydrocarbons and alcohols are much easier to handle than the lightest molecule in the universe.  We can capture and reuse CO2, which is also much easier to store than H2.  Carbon leakage can be replaced by a host of means, including the capture of carbon in waste streams.

A hydrogen economy means hydrogen leakage, and hydrogen leakage is not benign.  H2 diffuses past the tropopause "cold trap" into the stratosphere, where it oxidizes to water in the ozone layer.  This will increase the number and size of Polar Stratospheric Clouds, adding to ozone depletion.  Alcohols are too reactive to get beyond the troposphere.

H2 from renewable energy will be very affordable in the future, based on current trend in technologies.
The same technologies will make GHG-neutral carbon-based storable fuels affordable too, and they'll always be easier to handle.  Again, I'm looking for the rationale here.

Suppose for a minute we decide to be carbon-neutral by capturing and recycling carbon at the vehicle, rather than loading only hydrogen.  You can store a lot of CO2 in a tank at 1000 psi, and at the critical point the density is 0.464.  That's a carbon density of 0.127.  If the fuel was isobutanol at 33.0 MJ/kg heat of combustion and 0.649 carbon fraction, your 1 liter of critical CO2 starts from 0.196 kg of alcohol storing 6.46 MJ of chemical energy.  This is considerably greater than the energy of hydrogen, which only holds 4.7 MJ/liter at 700 bar (some 10 times the pressure of critical CO2).

The goals of the hydrogen economy can be achieved without using molecular hydrogen, and perhaps better.  This is one of many reasons we shouldn't be trying to pick H2 as the winner.

Roger Pham

To answer your question: "why is storage of H2 the "solution" to this?" the answer is simply: Because H2 is easy and cheap to make and can be made anywhere.

I can envision a scenario in which the use of H2 can completely be avoided by incorporating carbon into the hydrogen.
Recall that the energy from waste biomass, when converted to methane, can satisfy 1/3 of transportation requirement in the USA. Let's say that future vehicles will be twice as efficient as present-day vehicles. This means that waste biomass can do 2/3 transportation needs. Next, lets add the H2 made from renewable energy into the gasification vessel to double the methane yield from the process. Now, waste biomass + renewable-energy H2 can satisfy 4/3 of future transportation needs. Better yet, BEV's charged from renewable electricity and long-haul trucks and trains running off renewable electricity from overhead cables on major routes may satisfy 1/3-1/2 of transportation needs, depending on regions. The calculation is a bit messy, however, I can say that ~ 1/2 of waste biomass (+ renewable H2 incorporation) will be needed for transportation, reserving the other 1/2 for "rainy and winter days" electricity production.

So, I can see your point, we will get by, using 100% renewable energy without requiring any direct use of H2 at all. I thought about the above quite sometime ago. However, I further calculated that from a cost-effectiveness computation, methane from biomass gasification and hydrogenation will be significantly more costly than using H2 directly. The harvesting of waste biomass and chemical conversion process requires facilities that will require substantial investments that will need to amortize to the cost of the synthetic methane. The recently announced highly efficient and cost-effective hydromethanation of coal in Xinjiang can improve the cost equation if this technology can be applied to biomass hydrogen-methanation.

So, instead of asking why H2, I'd like to ask: Why not H2? Direct use of H2 can reduce energy cost to 1/2 that of synthetic methane.

WRT Ozone depletion, methane is actually worse than H2. See the following reference:

Roger Pham

Furthermore, ethanol and isobutanol synthesis from waste biomass will be quite expensive, and can't hardly take much renewable H2 incorporation as with synthetic methane. Methanol is easy to produce, but is highly toxic since ingestion of ~10 ml can cause blindness. Since it is miscible with water, 10ml of methanol in 500 ml of water will be quite undetectable, but very toxic. Imagine a tanker or pipeline rupture of methanol into a lake or water table (aquifiers)?


No matter how much you blather on the simple facts of people acrualy wanting the fuel cell cars.. people sooner then later being able to afford the cars and people being able to afford the fuel itself mean that fuel cell cars will come out and be a section of the car fleet.

This is no different then the we will have bevs no matter what because again the main reason is people want them followed closely by people being able to afford them and the power that runs them.

And the basic absolutely unaqrgueable reason both will be around is that both groups will always be around wanting both types of car.

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