Debunking the hydrogen economy

[kmarinas86]

The only way a hydrogen economy would make sense is if it produced energy (e.g. via fusion).

Without getting energy from hydrogen, fuel cell vehicles and etc are basically overly complicated batteries.

[Ygggdrasil]

However, batteries currently are not very good at storing energy and electric vehicle cannot travel distances comparable to gas powered vehicles. Using hydrogen as an intermediary for energy storage could allow them to act as a better "battery" with a greater range than electric cars.

However, I do agree that a lot more work is needed on hydrogen in order to determine whether it will actually be feasible. As you correctly mentioned, an environmentally friendly hydrogen economy relies on the development of a renewable energy infrastructure as hydrogen only stores energy. Furthermore, its not necessarily clear that battery technology won't improve, and it may also be more advantageous to change our driving habits to support the use of electric vehicles.

[mgb_phys]

Without getting energy from hydrogen, fuel cell vehicles and etc are basically overly complicated batteries.
It makes sense for transferring large amounts of energy large distancess
If you have geothermal (iceland) or solar (n. africa) it is easier to make hydrogren and ship that to LA than run a power line or ship recharged nicad batteries.
The infrastructure is more easily modified, lots of natural gas and LPG technology.

It's not clear if hydrogen powered cars make more sense than electric. Power densities are similair and both need to improve if they are going to be more than around-town subcompacts. Hydrogen fits the gas-station fillup / oil company model but electric lets you recharge at home overnight.

[WarPhalange]

Also, even using oil or coal power plants to get electricity and store it in hydrogen is more efficient than using gasoline automobiles, because it's easier to stay efficient on a large-scale than to have every driver take necessary steps to make their car more efficient.

[russ_watters]

However, batteries currently are not very good at storing energy and electric vehicle cannot travel distances comparable to gas powered vehicles. The way you worded it, it isn't true. Batteries store and recover energy at an efficiency of better than 90%. Fuel cells, depending on how the hydrogen is produced, only around 50%. Using hydrogen as an intermediary for energy storage could allow them to act as a better "battery" with a greater range than electric cars. Now the way that is worded, it could be true. Reglar batteries have some drawbacks, like weight, cost, nasty materials, and charging time. Fuel cells might be better in those respects.

[russ_watters]

Also, even using oil or coal power plants to get electricity and store it in hydrogen is more efficient than using gasoline automobiles, because it's easier to stay efficient on a large-scale than to have every driver take necessary steps to make their car more efficient.
That is true of battery-powered cars, but not true of fuel cell cars. Assuming probably too high estimates of 70% efficiency for both the electrolysis and the fuel cell, 60% efficiency for the power plant, and 90% for the motor, that gives you about 27% efficiency. A battery powered car loses about 7% in the power lines and the batteries, charger, and motors are all better than 90% efficiency. That gives a conservatively low estimate of 40% overall efficiency.

[Coin]

The point of hydrogen in the "hydrogen economy" is as a common medium for energy transport and storage. If you didn't understand this already then you don't understand the "hydrogen economy" enough to debunk it...

That is true of battery-powered cars, but not true of fuel cell cars. Assuming probably too high estimates of 70% efficiency for both the electrolysis and the fuel cell, 60% efficiency for the power plant, and 90% for the motor, that gives you about 27% efficiency. A battery powered car loses about 7% in the power lines and the batteries, charger, and motors are all better than 90% efficiency. That gives a conservatively low estimate of 40% overall efficiency.

That 7% sounds very optimistic, are you assuming the power was generated locally? What if the power was generated a long way away and was transported over long distance power lines, or was generated at some point in the past and stored? One assumes hydrogen, if it's treated like normal substance fuels, would be used this way, I don't know whether electricity can be transported and stored as easily or not...

[russ_watters]

That 7% sounds very optimistic, are you assuming the power was generated locally? What if the power was generated a long way away and was transported over long distance power lines, or was generated at some point in the past and stored? One assumes hydrogen, if it's treated like normal substance fuels, would be used this way, I don't know whether electricity can be transported and stored as easily or not... I'm talking about the transmission lines themselves and it is about 7%:
http://en.wikipedia.org/wiki/Electric_power_transmission#Losses

And I factored that into the batteries but not the hydrogen because I assumed the hydrogen would be produced at the power plant. Electric cars will almost certainly be recharged at home.

[Topher925]

estimates of 70% efficiency for both the electrolysis and the fuel cell

Didn't MIT just have a "break through" by using a new catalyst and cathode to have electrolysis operate at efficiencies of around 90%? Current PEM fuel cells operate around 50% efficiency although I think Honda's (FCX) is approaching 60%. I can see this number being 70% in ten years. And although it isn't hear yet solar thermolysis shows promise of some extremely high efficiencies.

One overlooked aspect of batteries is their disposal. They don't last forever, and most high capacity batts don't last longer than 500 cycles. Also you have to consider that all batteries self discharge. BTW, if you compare the Honda FCX to the Tesla Roadster, they both have about the same max distance. But the FCX does cost a hell of a lot more.

[mheslep]

Didn't MIT just have a "break through" by using a new catalyst and cathode to have electrolysis operate at efficiencies of around 90%? ...

Yes. Uses common materials and is highly efficient. Should be, finally, a practical and economic way to use electrical means to store energy in chemical form (H2).
http://www.sciencemag.org/cgi/content/full/1162018/DC2
http://www.technologyreview.com/article/21179/page4/

[mheslep]

...and most high capacity batts don't last longer than 500 cycles. ...That depends a great deal on the level of discharge, the top off charge, and temperature. If one mediates all these, which the Tesla roadster does and your laptop does not, the battery life will be greatly extended.

[Topher925]

....and your laptop does not...

My laptop has hardware designed to maximize battery fitness, doesn't yours. :confused:

Anyway, LiFe(P) has done a lot for battery durability but that comes at a pretty big hit of specific energy which in the long run kills efficiency. The lightest batts, Lipoly not Lion or LiFe(P), have very limited life spans even when properly used. I've never gotten more than 200 cycles out of my Lipos for my RC heli's while I could run NiMH for over a thousand.

[mheslep]

My laptop has hardware designed to maximize battery fitness, doesn't yours. :confused:
All the mfn's design to maximize operation time per single charge, as that's what is advertised and reviewed. Their first priority is to give you non-stop operation on that coast-to-coast air travel, lifecycle is an afterthought. Obviously laptops have no temperature stabilization on the battery. The Chevy Volt for instance will hold in reserve some percentage (10%?) of the battery charge, and they never top off the charge either, neither of which is provided by your laptop. Generally laptop charge circuitry is only tasked with limiting charge rates and Li ion safety issues.

[mheslep]

Of the several problems with an H2 economy by far the most intractable to my mind is the transportation and/or storage of H2 as a fuel. With some of the more recent developments I 've been musing that perhaps a solar/wind/grid based local roadside H2 station might start to make sense. Details below. First the problems w/ H2 up until now.

This chart lays it out nicely:
http://www.physorg.com/news85074285.html
To run an H2/fuel cell car, starting with 100kWh electric power one ends up w/ only 23kWh of tractive power delivered by the vehicle:
AC-DC: 95%
Electrolysis: 75%
Compression: 90%
Transport/transfer: 80%
Fuel Cell: 50%
Electric drive train: 90%

So far the logistics of providing roadside fueling of an H2 car has meant:
stage 1: a large electrolysis center somewhere w/ with a massive megawatt connection to the grid to make the H2 (or reforming from natural gas but lets drop the fossile source for this line). Then compression, storage, and transport to local road side stations. Note that it takes 15-20 tankers of compressed 3000 to 5000 psi H2 to deliver the energy equivalent of one gasoline tanker, and existing pipelines won't handle H2 at all.
stage 2: road side H2 station, storage again until delivered to the vehicle.

Now some musing on how this might be done differently, given recent developments:
-Nocera's efficient and cheap electrolysis breakthrough (linked above)
-Improving solar PV efficiency and technology, especially concentrated PV
-Electric transmission becoming more expensive and difficult.
These three lead me to the concept of a completely local, self sufficient H2 roadside station. Given: the average existing US gas station pumps 2000 gal/day. At 136Mjoule/gal-gasoline, thats 272000 Mjoule/day, or 76000 kW-hrs/day. Assuming the new H2/fuel cell cars are 3X more efficient than existing ICE cars, we need only a third, or 25300 kW-hrs/day of equivalent electrical energy.

Now, efficiencies. We need no AC/DC conversion. After 90% efficient Nocera on-site electrolysis and 90% efficient on-site compression we need 31234 kW-hrs/day. To get that from the grid means a 1.3MW average electric service at all 200,000 US filling stations, hard for both the local filling stations and the grid at large to accommodate, so lets try onsite generation.

Solar is a good fit here in a sunny climate because we're along side the highway, and because we don't care about variability. One just buffers enough H2 to stay ahead of demand. At a year round average of 7kW-hrs/m^2/day (http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/atlas/) we need 4500m^2 or 1.1 acres (with 100% collection): 16 acres of 7% thin film, 7.5 acres of traditional 12% Si PV, 5 acres of advanced 22% PV, 3 acres concentrator panels of triple-junction 37% PV cells (w/ tracking). Big interstate roadside stations, like this one (http://maps.google.com/maps?f=q&hl=en&geocode=&q=truck+stop+maryland&ie=UTF8&ll=39.140904,-76.844929&spn=0.002954,0.004828&t=h&z=18), have that kind of land to spare.

Cost? Solarbuzz says 22 cents/kWh (http://www.solarbuzz.com/statsCosts.htm) for traditional PV in sunny climates, or $6900/day for this scenario, plus the electrolysis, compression, and H2 storage gear. That's against $8000 per day for the gasoline station this H2 station replaces, so we're getting close. On the other hand, the triple-junction company Sunrgi (http://www.sunrgi.com/faq.html)claims they'll be doing 7 cents/kWh in a couple years. :uhh:

[Ygggdrasil]

Today's New York Times (http://www.nytimes.com/2008/08/27/business/27grid.html) had an interesting article about wind power that goes along the lines of mheslep's comment. Many wind farms have to shut down when the wind is too strong because they're generating too much energy for the power grid. This highlights a major problem with two of the primary sources of renewable energy (wind and solar): their outputs are highly variable and may not match peak times for energy demand. This is where hydrogen, as a means to store this energy that would otherwise go unharvested, comes in. This hydrogen could either be used as a buffer for days where the solar/wind generators can't meet demand and/or could be transported away for use as fuel.

Of course, there are still problems with transport and storage, but it seems like generating hydrogen may not be so much of an issue now. Personally, I think storing hydrogen in the solid state (e.g. as metal hydrides or adsorbed in nanomaterials) shows the most promise, but these solutions are still in the R&D stage.

[mheslep]

Yes efficient production of H2 would help the variability of renewable power like solar and wind in many applications but it doesn't by itself enable a nationwide solution. As that NYT piece shows, the power has to be eventually shipped over transmission lines from the wind belt or the solar belt to the demand areas - except for onsite bufferable problems like a fueling station.

[vanesch]

Given: the average existing US gas station pumps 2000 gal/day.

You mean your average highway station only has about 100-200 customers a day ?

[Topher925]

Non-baseload power generation is the biggest flaw with alternative power sources. I believe it was once estimated that wind power could never account for more than 7% of total power on the grid because of variability. The current bandaid for this is the use of flywheels, for example Beacon Power's flywheels: http://www.reuters.com/article/pressRelease/idUS174731+19-May-2008+BW20080519

I believe the only answer in the end will by an H2 economy.

mheslep, that article makes a strong argument but it includes a lot of unnecessary processes. H2 would obviously be created directly at the plant and then shipped, in which case the fast majority of the losses would be just to do to the transportation vehicle itself which given a few years of R&D will become pretty close to current electric vehicle efficiencies.

[mheslep]

You mean your average highway station only has about 100-200 customers a day ?That sound reasonable, I actually pumped gas as a kid, but I don't know. I used US daily 390 million gallons of gasoline / 200000 US gas stations.
www.eia.doe.gov/basics/quickoil.html

[mheslep]

Non-baseload power generation is the biggest flaw with alternative power sources. I believe it was once estimated that wind power could never account for more than 7% of total power on the grid because of variability. The current bandaid for this is the use of flywheels, for example Beacon Power's flywheels: http://www.reuters.com/article/pressRelease/idUS174731+19-May-2008+BW20080519

20%.
www.20percentwind.org

No doubt there are many storage methods possible. Pump storage and hydro has been the traditional load levelling go-to for the industry, geography/terrain permitting. At the moment Compressed Air seems to be the darling of DoE (one plant in operation), perhaps electrolysis-H2-gas turbine at NREL (prototype).
Distributed Energy Program: Compressed Air Energy Storage (http://www.eere.energy.gov/de/compressed_air.html)

[vanesch]

That sound reasonable, I actually pumped gas as a kid, but I don't know. I used US daily 390 million gallons of gasoline / 200000 US gas stations.
www.eia.doe.gov/basics/quickoil.html

It's funny. When I get to a highway station, I'm usually waiting in line with say, 1 or 2 customers before me, there are usually 6 - 10 lines, and it takes me about 5-10 min waiting time before it's my turn, so I'd say that we get a customer flow of about 5-10 customers/ 5 minutes, or 60-120 customer *an hour*. Now, I realise that this is not the same at 18 hr than at 2 am, but nevertheless...

[vanesch]

At the moment Compressed Air seems to be the darling of DoE (one plant in operation),

This seems one hell of a stupid storage, no ? You loose a lot of energy by adiabatic compression and cooling ! Or do they use a different technique (like keeping the hot air thermally insulated) ?

[Topher925]

As far as I know, they just pump air into caves which can behave as a huge heat sink. Yes it is a stupid inefficient way of storing power but you can store a LOT of it on the cheap. Its very unpractical to store, lets say, 20MWhs with some batteries.

[Ygggdrasil]

One idea that's been floated is around (vehicle-to-grid technology) is to use batteries in plug-in hybrids and other electric vehicles to act as a buffer by storing energy when demand is low and providing energy during peak demands. Of course, this won't work until electric cars become widespread, but it's an interesting idea.

http://www.sciencedaily.com/releases/2007/12/071203133532.htm

[mheslep]

It's funny. When I get to a highway station, I'm usually waiting in line with say, 1 or 2 customers before me, there are usually 6 - 10 lines, and it takes me about 5-10 min waiting time before it's my turn, so I'd say that we get a customer flow of about 5-10 customers/ 5 minutes, or 60-120 customer *an hour*. Now, I realise that this is not the same at 18 hr than at 2 am, but nevertheless...Wow. Where, France? I've rarely (70's embargo maybe) seen that kind of load anywhere in the US. I suppose the 2000g/day average is quite light for those interstate highway ten pump stations and heavy for the mom/pop two pump stations.

[mheslep]

This seems one hell of a stupid storage, no ? You loose a lot of energy by adiabatic compression and cooling ! Or do they use a different technique (like keeping the hot air thermally insulated) ?Yes that's the criticism. I wouldn't know the amount heat transfer to the surrounding rock over the time span - for wind it would be hours to a couple of days. I suppose the geology must be chosen carefully. The couple of existing plants use natural formations, perhaps modified.

[mheslep]

One idea that's been floated is around (vehicle-to-grid technology) is to use batteries in plug-in hybrids and other electric vehicles to act as a buffer by storing energy when demand is low and providing energy during peak demands. Of course, this won't work until electric cars become widespread, but it's an interesting idea.

http://www.sciencedaily.com/releases/2007/12/071203133532.htm
Some good work done on V2G by NREL as part of their wind program.
Poster:
www.nrel.gov/analysis/winds/pdfs/wind_phev_poster.pdf
Paper:
A Preliminary Assessment of. Plug-In Hybrid Electric Vehicles. on Wind Energy Markets (http://www.eere.energy.gov/afdc/pdfs/39729.pdf)
The authors show that with a large US fleet of PHEVs by 2020, the reserve capacity could ramp up to 250GW (25% of todays total grid capacity). That makes assumptions of 50% plug-in time, very capable PHEVs (60's), etc. (Figure 5).

Can plug-in hybrid electric vehicles keep the electric grid stable? (http://spectrum.ieee.org/oct07/5630)

[russ_watters]

This seems one hell of a stupid storage, no ? You loose a lot of energy by adiabatic compression and cooling ! Or do they use a different technique (like keeping the hot air thermally insulated) ?
I don't see it as being any worse than pumped-water storage. The point isn't in the efficiency, it is in finding a way to store a vast quantity of energy. Since at night you have a vast quantity of wasted capacity, you may as well use some of it to do some sort of storage.

France is all nuclear - what do they do at night?

[mheslep]

I think Vanesch was pointing out that possibility of energy loss in compressed storage. The compressed, necessarily hot, air could cool in fixed volume storage to the point where significant energy is lost (PV=NRT). The worse that could happen w/ pumped storage is evaporation?

[mheslep]

FYI
Compressed-air storage coming to wind power (http://news.cnet.com/8301-11128_3-10026958-54.html?tag=mncol;title)

A New Jersey company said on Tuesday it will invest $20 million over three years to develop an underground compressed-air storage system for wind turbines and other power sources, a sign of growing confidence in the technology.

Energy Storage and Power is a joint ventured formed by energy developer PSEG Global and Michael Nakhamkin, who designed the only compressed air-storage facility in the U.S.

With Compressed Air Energy Storage (CAES), air is pumped into underground formations, such as depleted natural gas wells or salt caverns, using a natural gas-powered machine. The pressured air is released later to drive a turbine to make electricity...

Battery makers also want to play at the grid MW level. A123 reportedly is the battery vendor for Chevy's PHEV.
A123 Systems plugs lithium-ion batteries into power grid (http://news.cnet.com/8301-11128_3-9976421-54.html)
...Fulop said that batteries can meet utility needs for grid stabilization, where a large amount of electricity is needed for a short amount of time.

"The technology can do it. Now it's a question of building the systems," he said. "Megawatt-level systems are all about systems integration."

In addition to batteries, utility-ready energy storage systems require electronics and thermal management systems, he said.
though at $500-1000 / kWh of Li ion I don't see how batteries compete. Perhaps they're cheaper at that scale and when mass is not important.

[russ_watters]

I think Vanesch was pointing out that possibility of energy loss in compressed storage. The compressed, necessarily hot, air could cool in fixed volume storage to the point where significant energy is lost (PV=NRT). The worse that could happen w/ pumped storage is evaporation?
No, the worst that happens with pumped-storage is the efficiency of the pump is only 60%, which is about the same as the efficiency of a good compressor.

Compressor efficiency ratings are almost always at room temperature output, meaning they take into account the heat generated in the compression and lost in the storage.

Heck, what do you think happens to water when you run it through a pump...?

[mheslep]

No, the worst that happens with pumped-storage is the efficiency of the pump is only 60%, which is about the same as the efficiency of a good compressor.

Compressor efficiency ratings are almost always at room temperature output, meaning they take into account the heat generated in the compression and lost in the storage.

Heck, what do you think happens to water when you run it through a pump...?Yes I understand there are necessarily losses in the act of storage and again on the recovery. I meant that while the storage system is loaded but idle, the compressed air system is still bleeding off energy as the cavern cools. Not so with elevated water.

[vanesch]

France is all nuclear - what do they do at night?

Well, you might be surprised, but most french nuclear power stations can follow load, they are not only working in baseload. They can ramp at 5% of nominal power per minute, as long as they stay between 30% and 100% of nominal capacity (below 30%, there are problems with Xe poisoning). They can even handle up to 10% "immediate" load change from their working point.

[russ_watters]

Yes I understand there are necessarily losses in the act of storage and again on the recovery. I meant that while the storage system is loaded but idle, the compressed air system is still bleeding off energy as the cavern cools. Not so with elevated water. We're talking past each other. What I'm saying is that it is generally assumed that that heat is lost in a compressed-air system. If the stored air is "still bleeding off energy as the cavern cools" then that means it hasn't lost all that heat - that's a bonus, not a penalty.

[mheslep]

We're talking past each other. What I'm saying is that it is generally assumed that that heat is lost in a compressed-air system. If the stored air is "still bleeding off energy as the cavern cools" then that means it hasn't lost all that heat - that's a bonus, not a penalty.Ah, thanks, I see your point.

[mheslep]

...I've been musing that perhaps a solar/wind/grid based local roadside H2 station might start to make sense. It turns out that the paper by Bossel "Does a Hydrogen Economy Make Sense" (www.efcf.com/reports/E21.pdf), 2006, dedicated a section to just this subject so I'm revisiting this post to compare. Bossel demolishes transportation of H2 and then logically turns to on-site production:
I. On-Site Generation of Hydrogen One option for providing hydrogen at filling stations and dispersed depots is on-site generation of the gas by electrolysis. Again, the energy needed to generate and compress hydrogen by this scheme is compared to the HHV energy content of the hydrogen transferred to cars. Natural gas reforming is not a sustainable solution and thus not considered for the reasons stated earlier...
Vanesch will like the next:
Consider a filling station now pumping 60 000 L[15850 gallons] of fuel (gasoline or diesel) into 1000 cars, trucks, or buses per day. This number is typical for service areas along European freeways. In most parts of the United States, many smaller filling stations are located roadside at freeway exits.60000L/day! Must have an on-site refinery! I had used 2000g/day for our 'smaller' stations.

Then on the efficiency of H2 vs gas fueled ICS vehicles, Bossel downrates my 3x efficiency advantage estimate to 1.5:
...However, hydrogen vehicles are assumed to have a 1.5 times higher tank-to-wheel efficiency than IC engine cars [29]. The frequently cited number of 2.5 cannot be justified any longer in light of the high efficiency of diesel or hybrid vehicles. In fact, the well-to-wheel studies of 2002 [8], [9] are based on lower heating values, optimistic assumptions of fuel cells, and disregard of the efficiency potentials of
diesel engines and hybrid systems. The shortcoming of LHV analyses is discussed in [30]. Furthermore, more recent well-to-wheel studies appropriately based on the higher heating values [10] do not identify hydrogen-fuelcell cars as the best transportation option. In fact, the efficiency of all-electric cars is three times better than for hydrogen-fuel-cell vehicles [31].I have not run down these references yet, no doubt some mention of variable displacement ICE and the like. Bossel does use the term 'potential' regarding high efficiency ICE, but point taken.

More:
Under the favorable assumption of a 1.5 advantage of hydrogen versus gasoline, 60 000 liters of fuel will be replaced by 12 000 kg of hydrogen per day. The
electrolyzer efficiency may be 75%. Also, losses occur in the ac–dc power conversion. Making 12 000 kg of hydrogen per day by electrolysis requires 25 MW of continuous power and 108 000 liters of water must be pumped and demineralized. Compression power is needed for storing the hydrogen to 10 MPa and for transfer at 40 MPa to vehicle tanks at 35 MPa. In all, to generate and store 12 000 kg of hydrogen per day, the filling station must be supplied with continuous electric power of about 28 MW. There are many sites in arid regions where neither the electricity nor the water is available for hydrogen production.My assumptions (vs Bossel): 3x better vehicle efficiency (vs 1.5), 90% MIT/Nocera electrolysis (vs 75%), no AC/DC conversion of DC on-site solar (vs 95%). Using my assumptions we have a 10.3MW (Euro size) fuel station. I only quarrel with his 1.5x vs 3x assumption at the front end: the numbers of Bossels on highly efficient ICE are beside the point, the 60000L/day figure must be today's consumption figure using '1x' cars of ~30mi/gal, not tomorrows better ICE, so the H2 converted fuel station, still serving '1000 cars', 90mi/gal equivalent, would only have to pump the equivalent of only 20000L, not 40000L. So Bossel's grid driven traditional electrolysis station should actually require 14MW.

Regardless, the large power connection drives home the point about the difficulty of connecting to the grid further adds to the case for doing solar on-site. I hadn't considered the water load which is substantial.

[Kasper_NYC]

This article is really interesting:

The Economics of Small to Medium Liquid Hydrogen Facilities

http://www.rmwsolutions.net/pub3.pdf

Otherwise I don't see easy at all to keep the hydrogen liquefied in a tank in ours cars... and just compressed doesn't make too much sense to me either. I guess we are gonna keep seeing hydrocarbons in our car for long more time.

From this Document: http://www.dotynmr.com/PDF/Doty_H2Price.pdf

".... A common 120-gallon compressed-air tank, which can store 0.57 kg of hydrogen at 15 atm., costs $730 [31]. At $1300/kg, this is 85 times as expensive as the diesel tank per energy storage, and it is 40 times more massive and over 200 times larger. Fifty (very large) 3000 psi aluminum scuba tanks could provide 10 kg of H2 storage for under $14,000 and only 750 kg [32]. Pricing data from the high-volume production of these tanks suggest high-volume production of 5000-10,000 psi tanks for storage of 3-8 kg of H2 might cost $600/kg of H2, which is about 30% less than suggested in an earlier study..."

Best.

[Topher925]

You have to look at the big picture when it comes to hydrogen storage. The tank itself might be cheaper for gasoline or diesel but you also need to include the fuel delivery system, including filters and a pump that operates at 100% output when ever the engine is running. Fuel pumps are known to fail along with being very inefficient and on many models fuel filters need replacing. A compressed tank of H2 should be a one time purchase with little or no maintenance through out its life. And while the tank may be heavier, the fuel it is carrying is definitely not. I don't have time to crunch the numbers but 50kwh of H2 will weigh a lot less than 50kwh of gasoline, including the tanks.

Honda has already shown that using compressed H2 can be done practically. Although a better method of storage is certainly welcome.

[mheslep]

You have to look at the big picture when it comes to hydrogen storage. We have been.
And while the tank may be heavier, the fuel it is carrying is definitely not. I don't have time to crunch the numbers but 50kwh of H2 will weigh a lot less than 50kwh of gasoline, including the tanks. No, in a road vehicle using steel tanks the H2 system will weigh a little more. Carbon fiber tanks can remedy that but they are $$$. More importantly, the compressed H2 tank volume is several times greater regardless of material, at least 3X at 10,000PSI assuming the vehicle needs only 1/3 the energy; if you want the same energy content as a tank of gasoline its ~7X more volume, i.e, a fuel tank with wheels.

Honda has already shown that using compressed H2 can be done practically. Although a better method of storage is certainly welcome.I'd say they've shown it can be done, period. Honda's cost to make the car is >$200k last I read. For reasons discussed above, one needs to stay close to the one or two H2 stations in your area if you have such a car, and the stations are not practical either. I also suspect the long term reliability of the fuel cell and its operation in cold climates is still an open question.

[gmax137]

Well, you might be surprised, but most french nuclear power stations can follow load, they are not only working in baseload. They can ramp at 5% of nominal power per minute, as long as they stay between 30% and 100% of nominal capacity (below 30%, there are problems with Xe poisoning). They can even handle up to 10% "immediate" load change from their working point.

The US nuclear units were also designed for daily load follow. They aren't operated that way, because once built, they provide the cheapest source of power. The fuel is almost free, compared to oil, gas, or even coal. So the power companies minimize their cost by running the nuclear units at full power, 24 x 7.

[RMForbes]

Why store hydrogen? Steam Reforming systems and even simple electrolysis systems are already available that can produce adequate hydrogen on-demand. Most of the energy consumption to produce compressed hydrogen gas is used to separate, purify and compress the gas for storage. If the goal is to produce a clean more efficient vehicle there is no need to separate the hydrogen out. Just produce it on board.

[Mech_Engineer]

Why store hydrogen? Steam Reforming systems and even simple electrolysis systems are already available that can produce adequate hydrogen on-demand. Most of the energy consumption to produce compressed hydrogen gas is used to separate, purify and compress the gas for storage. If the goal is to produce a clean more efficient vehicle there is no need to separate the hydrogen out. Just produce it on board.

Perhaps you could tell us all where the energy comes from to produce the hydrogen on-board in the first place?

Be warned that if you say "from burning some of the hydrogen on-board" I may end up having a slight aneurysm.

[mgb_phys]

Why store hydrogen?......If the goal is to produce a clean more efficient vehicle there is no need to separate the hydrogen out.
The goal is also to use hydrogen as a storage and transport mechanism so that energy generated a long way from the customer, geothermal in Hawaii or solar in Arizona, or intermittently, such as wind, can be used economically. Hydrogen is really more of a battery than a fuel.

[mheslep]

Why store hydrogen? ...Reforming CNG etc presupposes that CNG is your energy carrier. The idea behind the 'H economy' is that we get off fossil fuels and in that case how do we move energy around? It turns out fossil fuels are great energy carriers in BTU/lb and BTU/gal. Certainly electric power is a big part of that answer, but then 1) how do you handle variable electric power from wind, solar, etc., and 2) how do you store energy on anything disconnected from the grid e.g. vehicles.? As Greenspan said, the electric utilities 'have no inventory'.

Most of the posts in this thread discuss proposals and problems w/ either 1) or 2)

[Mech_Engineer]

It turns out fossil fuels are great energy carriers in BTU/lb and BTU/gal.

More important than the fact that fossil fuels have large amounts of energy per volume, is that the energy has already been captured and stored in them. If we manufacture Hydrogen for energy storage and transport purposes, we have to get that energy from somewhere.

Hydrogen : Oil :: Empty Gas Tank : Full Gas Tank

Hydrogen can be used to store and ship energy yes, but that energy has to be acquired and put into the Hydrogen first.

[mheslep]

More important than the fact that fossil fuels have large amounts of energy per volume, is that the energy has already been captured and stored in them. If we manufacture Hydrogen for energy storage and transport purposes, we have to get that energy from somewhere.

Hydrogen : Oil :: Empty Gas Tank : Full Gas Tank

Hydrogen can be used to store and ship energy yes, but that energy has to be acquired and put into the Hydrogen first.Yeah we need a sticky or something to say H2 is carrier, it has to be produced just like a battery has to be charged, then we just say that is a given and get on to the practical problem of how best to store and dispatch energy in a world where fossil fuel is unusable or too expensive.

[RMForbes]

First of all, I don't want anyone to have an aneurysm. Waste heat from the exhaust is a perfect source for energy recycling. Steam reformers use the heat energy directly to generate hydrogen and convert existing fuels to a cleaner burning more efficient fuel. TEG’s can be used to convert the waste heat energy into electricity. Some of this electrical energy can be used to produce hydrogen and oxygen gas through electrolysis. With millions of internal combustion engines already in use, doesn’t it make more sense to focus on modifying those first, before we create a whole new technology that requires a huge infrastructure that will take several years to develop. Don’t get me wrong, I am not saying we should stop developing hydrogen fuel cells. Just that there are huge gains that can be made much faster by increasing fuel economy on these existing engines while we are producing and developing new technologies.

Yes, hydrogen can be used as an energy storage and transfer mechanism but when injected into an internal combustion engine the combustion characteristics are changed. “Adding small amounts of hydrogen to gasoline produced efficient lean operation by increasing the apparent flame speed and reducing ignition lag” (ref 1977 NASA study). The stored energy of the hydrogen is not the mechanism that is responsible for this increase in efficiency. Hydrogen ignites much easier and burns many times faster than the gasoline or diesel. As it burns it ignites the primary fuel much faster and completely. The resulting combustion starts sooner and burns faster, so all the fuel is consumed long before the end of the power stroke. This is no unburnt fuel to be recycled by the EGR system or incinerated by the catalytic converter. The piston has more time and travel to absorb the energy of the resulting pressure wave and converting this energy into torque. Considerably less energy is lost as heat out the exhaust. By utilizing closed loop control systems and steam fuel reforming systems fuel efficiencies can be optimized by controlling the timing and concentrating full combustion to just a few degrees after top dead center of the power stroke.

[Coin]

First of all, I don't anyone to have an aneurysm. Waste heat from the exhaust is a perfect source for energy recycling...
So... this doesn't seem to really be addressing the idea of hydrogen at all? Hydrogen is being proposed as a method of getting energy into car engines, in response you are proposing a generalized method for making car engines more efficient period. While maybe more efficient engines are desirable, surely this is orthogonal to whether the engine is fueled by fossil fuels, hydrogen, or batteries...

Moreover if there is a method for making engines more efficient, I do not think the car companies need any specific extra inducement to use it? Better fuel efficiency is already not only a strong selling point for cars, but mandated by current law and stricter laws to come...

Yes, hydrogen can be used as an energy storage and transfer mechanism but when injected into an internal combustion engine the combustion characteristics are changed. “Adding small amounts of hydrogen to gasoline produced efficient lean operation by increasing the apparent flame speed and reducing ignition lag” (ref 1977 NASA study). The stored energy of the hydrogen is not the mechanism that is responsible for this increase in efficiency. Hydrogen ignites much easier and burns many times faster than the gasoline or diesel. As it burns it ignites the primary fuel much faster and completely. The resulting combustion starts sooner and burns faster, so all the fuel is consumed long before the end of the power stroke. This is no unburnt fuel to be recycled by the EGR system or incinerated by the catalytic converter. The piston has more time and travel to absorb the energy of the resulting pressure wave and converted to torque. Considerably less energy is lost as heat out the exhaust. By utilizing closed loop control systems and steam fuel reforming systems fuel efficiencies can be optimized by controlling the timing and concentrating full combustion to just a few degrees after top dead center of the power stroke.

So I'm not sure I understand what you're suggesting... I think hydrogen is not usually used in an internal combustion engine, my understanding was that hydrogen cars run on fuel cells. I know internal-combustion cars that use hydrogen instead of gasoline have been produced but I think they're mostly gimmicks.

However it sounds like what you're suggesting is a fossil fuel engine that also has a supply of hydrogen, it injects the hydrogen into the fossil fuels it burns, and this increases the performance above and beyond what a fossil fuel or hydrogen engine would be able to achieve on its own? Is this correct? Interesting...

[mheslep]

H2 boosting / electrolysis has been debunked on another thread:
http://www.physicsforums.com/showpost.php?p=1830195&postcount=12
http://www.physicsforums.com/showthread.php?p=1830195&highlight=waste#post1830195

[russ_watters]

So... this doesn't seem to really be addressing the idea of hydrogen at all? Hydrogen is being proposed as a method of getting energy into car engines, in response you are proposing a generalized method for making car engines more efficient period. While maybe more efficient engines are desirable, surely this is orthogonal to whether the engine is fueled by fossil fuels, hydrogen, or batteries...
Yes, and due to current technological hurdles, hydrogen production is not the most effective way to use that waste heat. Probably the best is an aft-end boiler to drive a turbine.

Of course, the turbine could turn a generator to make hydrogen, but it would probably be better to either connect the tubine to the drive shaft to boost mechanical power or produce energy to be stored in batteries, more like a conventional hybrid.

[russ_watters]

Yes, hydrogen can be used as an energy storage and transfer mechanism but when injected into an internal combustion engine the combustion characteristics are changed. “Adding small amounts of hydrogen to gasoline produced efficient lean operation by increasing the apparent flame speed and reducing ignition lag” (ref 1977 NASA study). We've discussed that study before. It claims a 9% improvement in fuel efficiency with hydrogen injection, which works out to (iirc) roughly 3x more energy than is contained in the hydrogen. But that is not enough to cover the energy required to produce the hydrogen.

[RMForbes]

"However it sounds like what you're suggesting is a fossil fuel engine that also has a supply of hydrogen, it injects the hydrogen into the fossil fuels it burns, and this increases the performance above and beyond what a fossil fuel or hydrogen engine would be able to achieve on its own? Is this correct? Interesting... "

Yes, there are systems that are currently available like systems that use a modified catalytic converter to capture waste energy from the exhaust to reform the fuel just before intake. By reforming the fuel in this way fuel economy is greatly increased. Hydrogen is produced in much higher concentrations than with electrolysis plus the primary fuel is also reduced to smaller components so they ignite easier and burn faster. Much closer to optimum fuel economies are being realized. While most of these systems currently operate on gasoline, alternative fuels have been shown to work even better. Fuels that mix well with water actually work the best, which also has the added advantage of not requiring an additional storage/delivery system for water. It’s already in the fuel.
.

[misgfool]

Today's New York Times (http://www.nytimes.com/2008/08/27/business/27grid.html) had an interesting article about wind power that goes along the lines of mheslep's comment. Many wind farms have to shut down when the wind is too strong because they're generating too much energy for the power grid.

Here in Europe the wind monstrosities have to shut down at high wind speeds to prevent them from harming themselves. The new 6 MW designs have blade length of up to 90 m and peak height is almost 200 m!

[RMForbes]

We've discussed that study before. It claims a 9% improvement in fuel efficiency with hydrogen injection, which works out to (iirc) roughly 3x more energy than is contained in the hydrogen. But that is not enough to cover the energy required to produce the hydrogen.

Sorry I missed the discussion. I just reread the study again and I don't see where they concluded that more energy was required to produce the hydrogen than was gained in fuel efficiency. I did see where they found that up to 37% less energy was lost out the exhaust.

[russ_watters]

That sentence was my conclusion using some rough calculations of the energy efficiency of the processes. The 9% efficiency improvement was using bottled hydrogen, not hydrogen generated by the car.

1 Joule of hydrogen acts like 3 joules when injected... but then the car only uses it at about 30% efficiency, the alternator 90% efficiency, and the electrolysis device only 60% efficiency. Multiplied together, that's a 16% efficient cycle. 16*3= 48% efficient. In other words, even with the efficiency increase of the engine, producing 1 J of hydrogen requires 2 J of gas.

[RMForbes]

That sentence was my conclusion using some rough calculations of the energy efficiency of the processes. The 9% efficiency improvement was using bottled hydrogen, not hydrogen generated by the car.

1 Joule of hydrogen acts like 3 joules when injected... but then the car only uses it at about 30% efficiency, the alternator 90% efficiency, and the electrolysis device only 60% efficiency. Multiplied together, that's a 16% efficient cycle. 16*3= 48% efficient. In other words, even with the efficiency increase of the engine, producing 1 J of hydrogen requires 2 J of gas.

While that may be the case, the study clearly showed that energy input was not the mechanism that created the increase in efficiency. The gain was made with less system loss on the back end. Less energy was lost out the exhaust, more energy from the combustion is captured by the piston and converted to torque. By reducing ignition lag and increasing flame speed the energy of combustion is concentrated closer to the beginning of the power stroke so the piston has more time and travel to convert more of this energy. Since nearly 85% of the energy produced by combustion is lost as heat out the exhaust, there is plenty of room for efficiency improvement here.

[mheslep]

That sentence was my conclusion using some rough calculations of the energy efficiency of the processes. The 9% efficiency improvement was using bottled hydrogen, not hydrogen generated by the car.

1 Joule of hydrogen acts like 3 joules when injected... That much? Surprising. I was under the impression that the burn was already highly efficient and most of the loss was in the nature of the mechanically driven heat engine regardless of burn efficiency.

but then the car only uses it at about 30% efficiency, the alternator 90% efficiency, and the electrolysis device only 60% efficiency. Multiplied together, that's a 16% efficient cycle. 16*3= 48% efficient. In other words, even with the efficiency increase of the engine, producing 1 J of hydrogen requires 2 J of gas.So that rules out on board generation but what if you bottle H2 locally? For instance: Some renewable source of energy, say solar -> electrolysis 75% (maybe 90 soon) -> compression to store 90% = 66% (81%); or cracking of methane and compress. From there I think an economic analysis is needed to justify the boosted gasoline-H2 efficiency.

[Topher925]

Propane makes a much better fuel additive then hydrogen. In ideal combustion, the hydrogen will never even be oxidized do to its hire ignition temperature.

Your efficiency doesn't come from burning hydrogen it comes from displacing nitrogen with oxygen. This means less losses at the throttle and less losses due to compression and heating of nitrogen gas which just absorbs heat.

[RMForbes]

Propane makes a much better fuel additive then hydrogen. In ideal combustion, the hydrogen will never even be oxidized do to its hire ignition temperature.

Your efficiency doesn't come from burning hydrogen it comes from displacing nitrogen with oxygen. This means less losses at the throttle and less losses due to compression and heating of nitrogen gas which just absorbs heat.

Actually propane is a better primary fuel source. It is already completely gaseous so it does not need extra time to be vaporized like liquid fuels. But nothing ignites easier or burns faster than hydrogen.. Hydrogen is the smallest, lightest, and most reactive element that is why it is at the top left side of the periodic chart of the elements. Hydrogen ignites easier and burns many times faster than any other element. Adding hydrogen to an internal combustion engine is like adding charcoal lighter fluid to your Bar-B-Q, it gets things started faster. This was the conclusion of the JPL and NASA studies from the 70's. Both studies concluded that adding small amounts of hydrogen reduces ignition lag and increases flame speed, which supports much leaner air/fuel mixtures. It does not have anything to do with adding or transferring additional energy to the combustion, the Second Law of Thermodynamics is therefore not being violated.

Without hydrogen injection gasoline is ignited by the spark plug several degrees before the beginning of the combustion/power stroke and is still burning when the piston reaches the bottom of this power stroke. The remaining unburnt fuel is then forced through the exhaust system to the EGR system to be recycled or to the catalytic converter to be incinerated (wasted). With hydrogen injection the combustion is much faster because the hydrogen burns quickly igniting the primary fuel from all sides at once. When proper engine timing and fuel mixture adjustments are made, the peak of the resulting pressure wave created by the combustion is higher (more energetic) and closer to the beginning of the power stroke because of this faster complete burn. Since most of the energy is released when the piston is near the top of the power stroke, more energy is able to be absorbed by the piston and converted to torque. Less energy is lost as heat through the exhaust. There is no unburnt fuel to be recycled by the EGR system or incinerated by the catalytic converter. A faster more efficient burn and less lost energy out the exhaust pipe means more power is converted to torque for power to the wheels, from equal amounts of energy input. This increase in over all system efficiency is the mechanism that creates increased fuel economy.

What the NASA study does show conclusively is that hydrogen injection does reduce ignition lag and increases flame speeds. Therefore, designing systems for optimum fuel efficiency requires the energy released from the combustion to be focused at the very beginning of the power stroke, where the piston has the maximum time and travel to absorb the energy of the resulting pressure wave. In their summary the NASA engineers concluded that this would be possible with fuel reforming systems controlled by a closed loop computerized control system. Unfortunately, they did not have these control systems readily available to them in 1977. But we have this type of technology in common use today. While, electrolysis based hydrogen injection may not be the answer to reach optimal fuel efficiencies, they are the easiest to produce and test. Significant fuel economy gains are being produced by individuals and companies around the world with well designed safe units. But, Steam reforming systems are where near optimal fuel efficiency gains are currently being realized.

Steam reforming systems utilize the waste heat from the exhaust system to produce hydrogen in higher concentrations than electrolysis and reform the gasoline (or any primary fuel) to smaller components that combust much faster. By using the hydrogen to reduce ignition lag to lowest possible time and reforming the fuel to be fully consumed in the shortest period possible, near optimal fuel efficiencies are being reached. At the same time greenhouse gas and hydrocarbon emissions are greatly reduced. While most of the steam reformer systems available are using gasoline, it has been shown that some alternative fuels work even better. Fuels that contain large amounts of water work the best, with the added advantage that they do not require any additional storage/delivery system for water. The water to produce hydrogen and steam for the reforming process is available directly from the fuel.

[russ_watters]

While that may be the case, the study clearly showed that energy input was not the mechanism that created the increase in efficiency. I didn't say it did. In fact, I said nothing whatsoever about the mechanism. I only analyzed the resulting numbers. You missed my point completely. The gain was made with less system loss on the back end. Less energy was lost out the exhaust, more energy from the combustion is captured by the piston and converted to torque. By reducing ignition lag and increasing flame speed the energy of combustion is concentrated closer to the beginning of the power stroke so the piston has more time and travel to convert more of this energy. That's all quite true, but the numbers are still the numbers. Since nearly 85% of the energy produced by combustion is lost as heat out the exhaust, there is plenty of room for efficiency improvement here. No, there isn't. A quick look at the efficiency equations or calculator for ideal Otto cycle shows the maximum possible efficiency is around 55-60%. It isn't possible - even in theory - to exceed that. And that's before you take away even the mechanical losses.

Another way to look at it: billions and billions of dollars have been pumped into researching these engines over the past hundred years. It would be illogical to believe that there is a shortcut to a massive improvement in efficiency. While, electrolysis based hydrogen injection may not be the answer to reach optimal fuel efficiencies, they are the easiest to produce and test. Significant fuel economy gains are being produced by individuals and companies around the world with well designed safe units. But, Steam reforming systems are where near optimal fuel efficiency gains are currently being realized. Please keep the forum guidelines in mind when discussing this subject. I'm giving quite a bit of leeway here, but the reality is that there is no scientific controversy on this issue, but there is a ton of crackpottery. Claims such as those are not supported by the science of the issue. It is a crackpot claim and I will not allow discussion of a crackpot claim here.

[russ_watters]

That much? Surprising. I was under the impression that the burn was already highly efficient and most of the loss was in the nature of the mechanically driven heat engine regardless of burn efficiency. Dunno, is 9% a lot? Keep in mind that when you add hydrogen, you are adding football rules to baseball. You can pour a billion dollars into a typical gas engine and only squeeze another percent or two efficiency out of it, but once you start playing with other fuels, you change the rules of the game somewhat. Since the 9% doesn't include the losses from generating the hydrogen or the cost of the generator, I don't consider 9% to be a lot. So that rules out on board generation but what if you bottle H2 locally? For instance: Some renewable source of energy.... Once you bring up renewable energy, there isn't anything left to talk about: if the energy is free, the energy is free. You can use it however you want. If you have free hydrogen on hand, why bother with the gasoline at all?

[mheslep]

...Once you bring up renewable energy, there isn't anything left to talk about: if the energy is free, the energy is free. You can use it however you want. If you have free hydrogen on hand, why bother with the gasoline at all?Well of course the energy is only 'free' in the sense that its never exhausted, it still has an economic cost and that can be compared to the $/bbl cost of fuel.

[RMForbes]

I didn't say it did. In fact, I said nothing whatsoever about the mechanism. I only analyzed the resulting numbers. You missed my point completely. That's all quite true, but the numbers are still the numbers. No, there isn't. A quick look at the efficiency equations or calculator for ideal Otto cycle shows the maximum possible efficiency is around 55-60%. It isn't possible - even in theory - to exceed that. And that's before you take away even the mechanical losses.

I guess I really don't understand. Are you saying that modern engines are already getting optimum fuel economy? It seems obvious to me that they aren't. Just the fact there is unburnt fuel left at the end that needs to be dealt with, is proof to me. Maybe I just don't get it.

Another way to look at it: billions and billions of dollars have been pumped into researching these engines over the past hundred years. It would be illogical to believe that there is a shortcut to a massive improvement in efficiency. Please keep the forum guidelines in mind when discussing this subject. I'm giving quite a bit of leeway here, but the reality is that there is no scientific controversy on this issue, but there is a ton of crackpottery. Claims such as those are not supported by the science of the issue. It is a crackpot claim and I will not allow discussion of a crackpot claim here.

Don't ask me to understand the motivations of the auto industry, it has never made sense to me. All I know is that these steam reforming systems have been in use for decades. The auto industry has purchased hundreds of patents for fuel reforming systems and sat on them. That is public record. Do you know why they have not developed any of these patents?

While I appreciate the leeway, I thought that this forum was about the hydrogen economy. I was not aware that because some people are exploiting the basic principles of hydrogen injection in ways that can only be considered scams, that all hydrogen based systems were automatically proven invalid. That sounds like throwing the baby out with the bath water, thinking to me. The facts are good people and good companies are already getting incredible results by developing these principles, saving millions of gallons of fossil fuels with real systems. They are nothing like the Water4Gas type junk. I hope you are referring to these MLM type websites, I really don't think you would call me a crackpot.

[russ_watters]

I guess I really don't understand. Are you saying that modern engines are already getting optimum fuel economy? It seems obvious to me that they aren't. No, I'm not. Fuel economy and thermodynamic efficiency are two very different things. You can, for example, decrease the weight and drag coefficient of a car and see a huge gain in fuel economy. But the engine that drives that car will have roughly the same thermodynamic efficiency as any other. The thermodynamic efficiency is what is pretty close to optimal.

That's for an engine powered exclusively by the Otto cycle, which includes virtually all of the hydrogen injection info we see (the ones that use the alternator and electrolysis). Connect an aft-end boiler of some sort and you can improve overall thermodynamic efficiency by quite a bit by adding a completely separate, secondary thermodynamic cycle.
Just the fact there is unburnt fuel left at the end that needs to be dealt with, is proof to me. Maybe I just don't get it. Now that's a third thing. Combustion efficiency is not the same as thermodynamic efficiency or fuel economy. Combustion efficiency of a modern car is on the order of 95% and can't get any higher. These devices do not affect the combustion efficiency, they effect the thermodynamic efficiency by changing where and how the energy is applied in the thermodynamic cycle, not by changing how much energy is expended in combustion. Combustion efficiency is a matter of chemistry: making sure you get all carbon dioxide and no carbon monoxide when you burn gas. And due to emissions regulations, the combustion process is very tightly computer controlled. Do you know why they have not developed any of these patents? They aren't technically/economically viable. While I appreciate the leeway, I thought that this forum was about the hydrogen economy. I was not aware that because some people are exploiting the basic principles of hydrogen injection in ways that can only be considered scams, that all hydrogen based systems were automatically proven invalid. That sounds like throwing the baby out with the bath water, thinking to me. The facts are good people and good companies are already getting incredible results by developing these principles, saving millions of gallons of fossil fuels with real systems. They are nothing like the Water4Gas type junk. I hope you are referring to these MLM type websites, I really don't think you would call me a crackpot. I was referring specifically to the electrolysis-based systems, which you cited in your claim. I don't know enough about the steam reforming ones to comment much, but it does have a similar smell to it.

[RMForbes]

Now that's a third thing. Combustion efficiency is not the same as thermodynamic efficiency or fuel economy. Combustion efficiency of a modern car is on the order of 95% and can't get any higher. These devices do not affect the combustion efficiency, they effect the thermodynamic efficiency by changing where and how the energy is applied in the thermodynamic cycle, not by changing how much energy is expended in combustion. Combustion efficiency is a matter of chemistry: making sure you get all carbon dioxide and no carbon monoxide when you burn gas. And due to emissions regulations, the combustion process is very tightly computer controlled.

I don’t want to belabor this point, but your suggestion that combustion efficiency is already near optimum is contrary to the conclusions of the NASA engineers. On the NASA channel early this week one of the NASA engineers was talking about engine efficiency in regards to an electric car they were testing. He stated that the electric car was about 85% efficient, all but 15% from the stored energy is converted to torque. He compared that to the gasoline engines, around 15% from the energy of combustion is converted to torque and 85% is lost as heat out the exhaust. He went on to say that diesel is only a couple points better than gasoline. In the 1977 study the NASA engineers found that adding hydrogen to gasoline reduced the energy lost as heat in the exhaust by as much as 37%. Some of that energy was lost to the cooling system but most was converted to torque. That sounds like a rather significant improvement in combustion efficiency to me, but I think we are just arguing symantics now.

Here is link to NASA study for those not familar with it.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770016170_1977016170.pdf

They aren't technically/economically viable. I was referring specifically to the electrolysis-based systems, which you cited in your claim. I don't know enough about the steam reforming ones to comment much, but it does have a similar smell to it.

Actually not true, most of the patents had working models that were well documented. Many of these basic ideas are being used in Europe but cannot be imported to the U.S. because of our protectionist laws. Do some research on SAAB engine enhancements, you may be surprised.

[vanesch]

Here is link to NASA study for those not familar with it.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770016170_1977016170.pdf


If you look at figure 11 on p 32, you see that the thermal efficiency of the motor goes from something like 29% for gasoline to 32% for gasoline/hydrogen.

That's the marginal gain Russ was talking about. And note that this was with a monster engine of 7.4 liters of 1969 :bugeye:

[russ_watters]

If you look at figure 11 on p 32, you see that the thermal efficiency of the motor goes from something like 29% for gasoline to 32% for gasoline/hydrogen. That's the marginal gain Russ was talking about. Right: about 9%. With bottled hydrogen (not generated by the engine). And note that this was with a monster engine of 7.4 liters of 1969 :bugeye: I didn't think about that - that's before computer control of the combustion process. The combusion efficiency today is considerably better than it was back then. Just throw a gigantic engine at the car and don't worry about how efficient it is. Even besides that, iirc, emissions of everything but carbon dioxide have dropped 90% since the 1970s due to technology forced by regulation.

And again, that 9% is not combustion efficiency, it is thermodynamic efficiency. Though, a lot of the thermodynamic efficiency gain in the paper probably comes from gains in combustion efficiency due to the poor combustion efficiency at the time (as vanesch pointed out). RC, you really need to start paying attention to the difference.

[mheslep]

I don’t want to belabor this point, but your suggestion that combustion efficiency is already near optimum is contrary to the conclusions of the NASA engineers. On the NASA channel early this week one of the NASA engineers was talking about engine efficiency in regards to an electric car they were testing. He stated that the electric car was about 85% efficient, all but 15% from the stored energy is converted to torque. He compared that to the gasoline engines, around 15% from the energy of combustion is converted to torque and 85% is lost as heat out the exhaust. He went on to say that diesel is only a couple points better than gasoline. In the 1977 study the NASA engineers found that adding hydrogen to gasoline reduced the energy lost as heat in the exhaust by as much as 37%. A heat engine such as the internal combustion engine can never be as efficient as the electric drive train. The heat engine efficiency is limited by thermodynamics.

[buffordboy23]

Here's some work that focuses on hydrogen supplementation via a plasmatron gas reformer developed by researchers at MIT. There are some pretty outrageous claims for efficiency improvements in the pdf file.

http://www.psfc.mit.edu/research/plasma_tech/PDF/dan_cps.pdf

http://web.mit.edu/newsoffice/2003/plasmatron.html

[russ_watters]

I don’t want to belabor this point, but your suggestion that combustion efficiency is already near optimum is contrary to the conclusions of the NASA engineers. As I have demonstrated, no it isn't. Heck, my company has a combustion gas analyzer. If you want, I'll stick it up the tailpipe of my car (already done that when I learned to use it) and take a picture of the output! On the NASA channel early this week one of the NASA engineers was talking about engine efficiency in regards to an electric car they were testing. He stated that the electric car was about 85% efficient, all but 15% from the stored energy is converted to torque. He compared that to the gasoline engines, around 15% from the energy of combustion is converted to torque and 85% is lost as heat out the exhaust. You threw a lot of scientific words around in previous posts, but this paragraph shows you really have no idea what thermodynamics even is. Gas engines are thermodynamic engines. Electric motors are not. Electric motors can be up to about 96% efficient at converting electrical energy to mechanical energy. But thermodynamic engines that use the Otto cycle can only be about 50% efficient at converting heat energy to mechanical energy. They are a completely different animal. You really need to get onboard with this concept. If you don't understand why it is, you need to learn. He went on to say that diesel is only a couple points better than gasoline. Yes, the Otto and diesel cycles are similar. The biggest difference is the way the fuel burns and what it allows to be done: higher compression ratios in diesels. In the 1977 study the NASA engineers found that adding hydrogen to gasoline reduced the energy lost as heat in the exhaust by as much as 37%. Some of that energy was lost to the cooling system but most was converted to torque. That sounds like a rather significant improvement in combustion efficiency to me, but I think we are just arguing symantics now.

Here is link to NASA study for those not familar with it.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770016170_1977016170.pdf As vanesch noted, you aren't properly analyzing the results. The drop in exhaust temp was largely due to running the engine lean, but that isn't directly translateable to thermodynamic efficiency (someone mentioned it before: less fire + more air = cooler exhaust, but not necessarily improved efficiency). Not to worry, though: Thermodynamic efficiency was specifically listed in the results. Actually not true, most of the patents had working models that were well documented. Many of these basic ideas are being used in Europe but cannot be imported to the U.S. because of our protectionist laws. Do some research on SAAB engine enhancements, you may be surprised. No, RC. Now you're dealing with both crackpottery and conspiracy theory. There is no mass production vehicle in any country that utilizes hydrogen generation/injection.

[russ_watters]

Here's some work that focuses on hydrogen supplementation via a plasmatron gas reformer developed by researchers at MIT. There are some pretty outrageous claims for efficiency improvements in the pdf file.

http://www.psfc.mit.edu/research/plasma_tech/PDF/dan_cps.pdf Now that's interesting. It says that by using hydrogen injection, you can increase the effective octane number. This does nothing whatsoever for an existing car engine, but it would allow the use of higher compression ratio engines, which is the key to higher thermodynamic efficiency. I don't know why they mention turbochargers, though - those are an efficiency improvement you can already bolt to just about any car.

[buffordboy23]

I don't know why they mention turbochargers, though - those are an efficiency improvement you can already bolt to just about any car.

The turbocharger would likely permit the car to run ultralean. The hydrogen would protect the engine due to its influence on combustion properties. Efficiency will increase.

The NASA article posted by RMForbes actually looked at hydrogen being used to extend the lean operating limit of an engine.

[RMForbes]

You threw a lot of scientific words around in previous posts, but this paragraph shows you really have no idea what thermodynamics even is......Gas engines are thermodynamic engines.....You really need to get onboard with this concept. If you don't understand why it is, you need to learn....No, RC. Now you're dealing with both crackpottery and conspiracy theory. There is no mass production vehicle in any country that utilizes hydrogen generation/injection.

You are right, I'm not a scientist. I'm a technician by profession. I take ideas from the researchers, designs from the engineers, and make them work. I may not have the terminology correct but I understand the concepts. I know these technologies are real by hands-on experience. I have done several experiments, some successes and some failures. I installed one of my successes on my personal vehicle almost a year ago. It still works great. Through experimentation is where real knowledge is gained. Dismissing ideas, no matter how far out they seem to you without experimenting, is not good science. I cannot remember any major innovation that was not called a crackpot idea by the people of the day. I happened onto a website the other day that listed just about every technology in common use today and the reactions by the respected people of that time as they demeaned the technologies. It was enlightening.

I suggest you review the MIT link again. Do you really think they are the only facility researching this technology or developing similar products?

I can understand your comment about conspiracies, but just because I think they are out to get us, doesn't mean they aren't.
Do I believe that the Oil industry has too much power? aaaaaaaaa yes!
Do I believe that they have used their power to stifle new technologies that threaten their market dominance? Guilty.
Have their lobbyists written most of the current legislation regulating their industry? Without a doubt.

[russ_watters]

I may not have the terminology correct but I understand the concepts. No, you clearly do not. Dismissing ideas, no matter how far out they seem to you without experimenting, is not good science. I cannot remember any major innovation that was not called a crackpot idea by the people of the day. Those are common crackpot fallacies about science. They just plain aren't true. First, a good experiment is based on pre-existing science. Second, good science is recognized by scientists virtually instantly. Common [wrong] examples often thrown around on that are Einstein's Relativity (it really was recognized quickly) and breaking the sound barrier (scientists did not think it was impossible). I happened onto a website the other day that listed just about every technology in common use today and the reactions by the respected people of that time as they demeaned the technologies. It was enlightening. I really would be curious to see it.

[vanesch]

I happened onto a website the other day that listed just about every technology in common use today and the reactions by the respected people of that time as they demeaned the technologies. It was enlightening.


People can make mistakes... in both directions. Here's a funny museum of great inventions that didn't work:
http://www.lhup.edu/~dsimanek/museum/unwork.htm

(now that I think of it, I think it was Russ who showed it to me first :tongue: )

Read especially http://www.lhup.edu/~dsimanek/museum/impossible.htm

Now, I know we're not talking about perpetuum mobile here, but the ideas apply all the same.

[buffordboy23]

Here is a wikipedia link that discusses hydrogen fuel-enhancement. There are a lot of cited sources that discuss both positive and negative results.

http://en.wikipedia.org/wiki/Hydrogen_Fuel_Injection

[russ_watters]

I thought someone said earlier you could produce hydrogen via steam reforming of water. Part of the reason I didn't comment on that before is I hadn't heard of it and didn't know how it worked. The Wiki talks about steam reforming of methane. No doubt, you can increase the gasoline fuel efficiency of a car by adding a second ready-to-burn fuel to it. I guess the real question would be does the hydrogen provide more of a benefit than if you had just injected the methane itself into the engine. Methane is already quite a good fuel.

[RMForbes]

No, you clearly do not.

Please, instruct me to which concept I don't understand. At least, I am willing to admit when I don't get it exactly right. Or are you calling the guys at MIT crackpots too? This technology is far too important to be dismissed out of hand. We have the opportunity to drastically reduce emissions and end our countries dependence on foreign oil within just two to five years with a concentrated focused effort. But first people like you must stop ignoring the proof and help us work out the details. We have to start working together.

Those are common crackpot fallacies about science. They just plain aren't true. First, a good experiment is based on pre-existing science. Second, good science is recognized by scientists virtually instantly. Common [wrong] examples often thrown around on that are Einstein's Relativity (it really was recognized quickly) and breaking the sound barrier (scientists did not think it was impossible). I really would be curious to see it.

I understand what you are saying, but that is not exactly what I was taught in college. However, that was quite a few years ago now and things may have changed. I thought you first observed a process in nature then designed an experiment so that the processes can be revealed. We were taught that preconceptions usually taint the experiment. Designing a good experiment so that all is revealed, is actually an art form. I guess they now teach that there is no need to experiment if you are sure that the observed process can't possibly work.

http://www.null-hypothesis.co.uk/science/strange-but-true/item/invention_failure_never_work_disaster

I especially like the last one. "X-rays are a Hoax" Lord Kelvin ca. 1900

[vanesch]

Please, instruct me to which concept I don't understand.

I think Russ is pointing you to the Carnot efficiency of a thermal engine.

[Topher925]

I think Russ is pointing you to the Carnot efficiency of a thermal engine.

And this the Gibbs free energy for thermodynamic efficiency.

Can we get back to battery vs. hydrogen economy yet? I've seen this same conversation on at least 5 other forums.

http://coreygilmore.com/blog/wp-content/uploads/2007/08/beating_a_dead_horse.jpg

[RMForbes]

I think Russ is pointing you to the Carnot efficiency of a thermal engine.

While I agree that mathematical models are very useful but these two do not allow combustion speed to be a variable. Do you have a model where combustion speeds can be varied to show the effect on efficiency? This would be useful.

By the way, I just received an email from the CEO of Dutchman Enterprises. They have announced a partnership with Ford Motor Company to supply their HAFC (hydrogen assist fuel cell) and PICC (Pre Ignition Catalytic Converter) for their SUV and truck lines. At least someone is starting to take this seriously.

[russ_watters]

Please, instruct me to which concept I don't understand. There are several, but the biggest are that you don't understand the different measures/types of efficiency and how they are arrived at. Ie, you have said you think there is a lot of combustion efficiency to be gained (when, in fact, it is already well in excess of 90%) and that there is a lot of thermodynamic efficiency to be gained (when, in fact, it has a real, hard limit of around 50%). Or are you calling the guys at MIT crackpots too? No. You are just reading things in these papers that aren't there.
This technology is far too important to be dismissed out of hand. We have the opportunity to drastically reduce emissions and end our countries dependence on foreign oil within just two to five years with a concentrated focused effort. No, we don't. But first people like you must stop ignoring the proof and help us work out the details. We have to start working together. You need to learn the science that will tell you where the boundaries of technology are. The "proof" does not say what you think it says. I have explained quite succinctly (and you have completely ignored) what the papers actually say. http://www.null-hypothesis.co.uk/science/strange-but-true/item/invention_failure_never_work_disaster

I especially like the last one. "X-rays are a Hoax" Lord Kelvin ca. 1900 Though that site is great fodder for crackpots, the vast majority of the quotes do not come from scientists and those that do are more about viability than possibility. While I agree that mathematical models are very useful but these two do not allow combustion speed to be a variable. Do you have a model where combustion speeds can be varied to show the effect on efficiency? This would be useful. An "ideal" model assumes perfection in everything including combustion speed. Thus it provides an upper boundary based on the assumption that every possible source of inefficiency, including improper timing of the combustion, can be overcome. By comparing the ideal to the actual, you can determine exactly how much room there is for technology to improve a thermodynamic device.

[Ivan Seeking]

RMForbes, no one here is being overly negative. These concepts are well understood and have been for over a century. The fact is that if this was truly a viable technology, there would be no need to argue for it.

Hydrogen is a great energy carrier - one that is relatively easy to make. But we do have to make it, so it is not an energy source. There is no mystery here.

[vanesch]

While I agree that mathematical models are very useful but these two do not allow combustion speed to be a variable. Do you have a model where combustion speeds can be varied to show the effect on efficiency? This would be useful.


The Carnot efficiency is a maximal efficiency that is theoretically possible in the conversion of heat into useful work - it doesn't have anything to do with a specific process. It is pretty fundamental. So given the combustion temperature of the ideal fuel mixture, and the temperature of the environment, one can easily calculate what is the maximal fraction of the thermal energy that could, by an imaginary engine of just any type, be converted in mechanical work.

The formula is extremely simple: that fraction is equal to 1 - T2/T1, where T2 is the temperature of the environment (in Kelvin), and T1 is the temperature of the combustion temperature (also in Kelvin).

For instance, consider boiling water at 100 centigrade, or 373 K, and the environment at 300K. Well, no matter what kind of machine you build, it will not be able to convert more than 1 - 300/373 = 19.5% of the heat that makes the water boil, into mechanical work.

If one goes in somewhat more detail of the specific process at hand, such as using the ideal gas law, and a compression, burning and expansion stage, one can get sometimes more detailed estimates of what is *in principle* possible.

In our example, if you have a genuine working steam engine which converts, say, 17% of the heat into work, then you have a pretty good machine, and you will only be able to improve it with about 2% absolulte, or something like 10% relative percents.

[RMForbes]

RMForbes, no one here is being overly negative. These concepts are well understood and have been for over a century. The fact is that if this was truly a viable technology, there would be no need to argue for it.

Hydrogen is a great energy carrier - one that is relatively easy to make. But we do have to make it, so it is not an energy source. There is no mystery here.

Again, I agree these processes have been well understood for almost as long as the internal combustion engine itself. So have steam reforming systems and alternative fuels. And yes, hydrogen is an excellent energy transfer agent, but again that is not what makes hydrogen enrichment work. Hydrogen reduces ignition lag and speeds combustion which allows the conversion more energy to torque instead of heat. Now, that sounds like an increase in efficiency to me but you all disagree. So can we say it increases gasolines octane?

[RMForbes]

I thought someone said earlier you could produce hydrogen via steam reforming of water. Part of the reason I didn't comment on that before is I hadn't heard of it and didn't know how it worked. The Wiki talks about steam reforming of methane. No doubt, you can increase the gasoline fuel efficiency of a car by adding a second ready-to-burn fuel to it. I guess the real question would be does the hydrogen provide more of a benefit than if you had just injected the methane itself into the engine. Methane is already quite a good fuel.

I was referring to an article I read on a alternative fuels website. You misunderstood my point. Here is a short quote to make things more clear;

”The main problem with ethanol is that the majority of engines on the road today are not designed for it. The exception is the Saab 9-5 Biopower engine, which IS optimized for ethanol. It outperforms gasoline, getting 20% more power, 16% greater torque, and 10% better mileage. The Lotus Exige 265E “Flexi” gets 45 more horse power on E85 than it gets on gasoline. Within the next two years, Suzuki, Ford, GM and numerous other car makers will introduce engines which exploit the advantages of ethanol, for its high octane and compatibility with water. Our system of blending 15% gasoline into ethanol is not necessary. Ethanol can be denatured without using gasoline. That was how politicians created an incentive for oil companies to distribute ethanol, by giving them a 51 cent per gallon tax credit to blend it with gasoline. Problem is, ethanol performs better when it’s mixed with water rather than gasoline. This is called hydrous ethanol. Nothing new. In the 1920's, the model A Ford cars and trucks ran on 165 proof ethanol, 17.5% water and 82.5% ethanol. Recently, a Pratt Community College engine testing team lead by instructor Greg Bacon, mixed 20% water with pure ethanol, and efficiency in the combustion chamber doubled. When the ethanol explodes, the water instantly turns into additional power in the form of steam and also provides hydrogen and oxygen inside the cylinder. Next year, Ford is introducing the EcoBoost engine, which may also have advanced ethanol technology that doubles efficiency. Brazil has been using 4% hydrous ethanol for years. They laughed at us when we started mixing ethanol with gasoline. Phil Ratte, Mechanical Engineer, BME University of Minnesota said: “From 1981 to 1989, I worked with Herb Hansen, who had been an engineer on a WW II submarine, and a former captain of a nuclear submarine. We developed two prototype cars, a Ford Pinto Station Wagon and a Mitsubishi Sedan, that ran as well on 65 proof ethanol (2/3 water and 1/3 ethanol) as they did on unleaded regular gas.” What is the one thing that the big oil companies fear the most? Water. The State of Louisiana now has an experimental hydrous ethanol program that may also be replicated in other states. Dongfeng, a major Chinese auto maker is introducing a car this year, with a slightly modified fuel system, that runs on 65% ethanol and 35% water. They claim hydrogen is formed. Toyota also has a similar hydrous ethanol prototype that produces on board hydrogen. The BTU argument that ethanol is inferior to diesel and gasoline is not valid. Since ethanol is water soluble and high octane, with advanced engine technology, it can outperform gasoline 2 to 1 or better. Major automakers are scheduled to produce smaller, lighter, high compression, turbocharged ethanol optimized engines that are far more efficient than current gasoline and diesel engines. And the fuel will be cheaper. If you prefer an ethanol powered fuel cell, the Swift Direct Proton Fuel Cell developed by Purdue University’s Research Park in West Lafayette, Indiana is about $2,000, only 1/10 the price of a hydrogen fuel cell. Maybe that’s why Toyota is building ethanol plants in Brazil, and GM is investing in ethanol development in the U. S…They must know something we don’t know about ethanol. “

[Topher925]

The BTU argument that ethanol is inferior to diesel and gasoline is not valid. Since ethanol is water soluble and high octane, with advanced engine technology, it can outperform gasoline 2 to 1 or better.

How can the BTU argument not be valid? So because a substance A has 85% of the internal energy of substance B, substance A can produce twice the energy as B because it has a higher octane rating? Do you even know what an octane rating (R+M test) means?

RMF, you really need to stop posting your propaganda and go read some books. Ethanol is not a viable energy source, its actually a very poor one. The only reason E85 and all its hype was created was because the US had a huge surplus of corn. Thats it. Not because it makes some "super duper" fuel source.

[RMForbes]

How can the BTU argument not be valid? So because a substance A has 85% of the internal energy of substance B, substance A can produce twice the energy as B because it has a higher octane rating? Do you even know what an octane rating (R+M test) means?

RMF, you really need to stop posting your propaganda and go read some books. Ethanol is not a viable energy source, its actually a very poor one. The only reason E85 and all its hype was created was because the US had a huge surplus of corn. Thats it. Not because it makes some "super duper" fuel source.

It's not my propaganda! This is a paragraph that I copied from a E-zine on the Green Fuels website. I made no value judgement on it, you did.

[Topher925]

It's not my propaganda! This is a paragraph that I copied from a E-zine on the Green Fuels website. I made no value judgement on it, you did.

Oh ok, it must be true then. :rolleyes:

[RMForbes]

Oh ok, it must be true then. :rolleyes:

I don't know. But they did give references that you could check out without much effort. Do you know how to do a Google search?

[Ivan Seeking]

Again, I agree these processes have been well understood for almost as long as the internal combustion engine itself. So have steam reforming systems and alternative fuels. And yes, hydrogen is an excellent energy transfer agent, but again that is not what makes hydrogen enrichment work. Hydrogen reduces ignition lag and speeds combustion which allows the conversion more energy to torque instead of heat. Now, that sounds like an increase in efficiency to me but you all disagree. So can we say it increases gasolines octane?

You keep missing the point. Let's assume hydrogen enrichment works, which it probably does. This does not speak to the complete efficiency of the process. There are more losses associated with producing the hydrogen than you will get back through increased efficiencies. The problem with hydrogen is producing the stuff.

Also, you can have whatever octane rating that you wish, but in the end you can't beat conservation of energy.

[Ivan Seeking]

As for Green Fuels, they make a lot of funny claims. For example, here they are discussing a particular interest of mine - biodiesel from algae:

The Vertigro Bio Reactor System has been designed to avoid both problems. Algae is grown within plastic bubbles hanging from racks in a greenhouse. Vertigro is a joint venture by and Global Green Solutions, a giant with offices in El Paso, Vancouver, London, Brussels and Johannesburg, and Valcent Products of Texas. During a 90-day continual production test, algae was being harvested at an average of one gram (dry weight) per liter, which the company estimates would equate to 33,000 gallons of algae oil per acre per year. Such an output is a third more than a pond system could produce, the team estimates.
http://www.greenfuelsforecast.com/ArticleDetails.php?articleID=481

It has been calculated that there is a net upper limit of about 10,000 gallons per acre-year based on the available energy input, which is absolute. The claim of 33,000 gallons is ridiculous.

[buffordboy23]

Hydrogen enrichment does work for lean engine operation. This is a condition when there is more air than at stoichiometric. Hydrogen makes the air/fuel mixture more homogeneous, which permits a more efficient combustion of gasoline during such conditions and smooths out the large temperature gradients associated with localized fuel charges. By having more air in the combustion cylinder, more work on the piston can be done, especially at higher compression ratios, because less heat from combustion is transferred to cylinder walls.

As for hydrogen enrichment at stoichiometric conditions, this is extremely questionable. I haven't seen any peer-reviewed studies that address this specific question, so this suggests that it is not a viable option. A while ago, I remember reading an article that looked at this aspect during a combustion simulation. If I recall correctly, the thermal efficiency increased by 2% but I forget what the assumed hydrogen flow rate was during the simulation. This efficiency improvement does not appear to compensate for the energy needs to produce hydrogen. If I find the article, I will post the data.

Although your argument makes sense Ivan Seeking, I am not fully convinced. The reason why is because hydrogen addition will likely change the combustion products, which could affect sensor data. If sensor data is affected is such a way, then it may be possible to "trick" your car into running lean, which may increase fuel economy but yet could be damaging in the long-term to your engine. For example, if hydrogen addition causes more gasoline to be combusted, which would be no more than 1% since most fuel is combusted anyways, then there is a reduction of free oxygen in the exhaust products. As a consequence, the O2 sensor would measure that the car is running "rich" for some throttle position, which could cause the ECU to shorten the fuel pulse-width to obtain the required free-oxygen products. Thus the car is now operating lean, and it could be possible to obtain an improvement in fuel economy. This is a hypothesis that I plan to test in the upcoming months by using an OBD-II interface and laptop computer to measure sensor data.

In regards to the hydrogen economy, I see that it will not be feasible for a long time, since many breakthroughs are needed, like storage, production, infrastructure, etc. What does make sense to me is that gasoline-hydrogen automobile hybrids, with the appropriate engine modifications for lean operation and machinery for producing sufficient quantities of hydrogen on-board, could become common in the near future. Such vehicles would have improved fuel economy and reduced emissions.

[mheslep]

As for Green Fuels, they make a lot of funny claims. For example, here they are discussing a particular interest of mine - biodiesel from algae:


http://www.greenfuelsforecast.com/ArticleDetails.php?articleID=481

It has been calculated that there is a net upper limit of about 10,000 gallons per acre-year based on the available energy input, which is absolute. The claim of 33,000 gallons is ridiculous.Unless they went vertical? Probably still ridiculous.

[RMForbes]

You keep missing the point. Let's assume hydrogen enrichment works, which it probably does. This does not speak to the complete efficiency of the process. There are more losses associated with producing the hydrogen than you will get back through increased efficiencies. The problem with hydrogen is producing the stuff.

Also, you can have whatever octane rating that you wish, but in the end you can't beat conservation of energy.

I don't think I'm the one missing the point, I think you guys are trying to pull a Sarah Palin on me. (Half joking) Where we are having an issue is how much hydrogen it takes to maintain lean engine operation. You like most of the researchers (until quite recently) have ASSUMED it would require a rather large amount. That is not the case; those of us that have been experimenting have found positive results with as little as 3 to 4 grams/hour. That amount of hydrogen can easily be produced by a 350 watt device. But if you insist that more hydrogen would be required, try using the waste heat from the exhaust to generate steam and then run that through a magnetic field or around charged plates to disassociate the hydrogen and oxygen gases. Much more hydrogen can be produced this way by using waste heat energy.

[Topher925]

Although your argument makes sense Ivan Seeking, I am not fully convinced. The reason why is because hydrogen addition will likely change the combustion products, which could affect sensor data. If sensor data is affected is such a way, then it may be possible to "trick" your car into running lean, which may increase fuel economy but yet could be damaging in the long-term to your engine. For example, if hydrogen addition causes more gasoline to be combusted, which would be no more than 1% since most fuel is combusted anyways, then there is a reduction of free oxygen in the exhaust products. As a consequence, the O2 sensor would measure that the car is running "rich" for some throttle position, which could cause the ECU to shorten the fuel pulse-width to obtain the required free-oxygen products. Thus the car is now operating lean, and it could be possible to obtain an improvement in fuel economy. This is a hypothesis that I plan to test in the upcoming months by using an OBD-II interface and laptop computer to measure sensor data.

This is actually the case for most hydrogen assisted do it yer-self kits. Not only does the ECU lean the engine due to bad sensor data but most kits actually come with a unit to emulate the air sensor past the throttle body causing the ECU to run the engine lean also. I haven't seen any results of this lean operating condition but I am sure that as more garage scientists put these things in their cars you will start seeing the longer term affects. Not to mention the affects of the metals in the engine becoming hydrides.

[RMForbes]

This is actually the case for most hydrogen assisted do it yer-self kits. Not only does the ECU lean the engine due to bad sensor data but most kits actually come with a unit to emulate the air sensor past the throttle body causing the ECU to run the engine lean also. I haven't seen any results of this lean operating condition but I am sure that as more garage scientists put these things in their cars you will start seeing the longer term affects. Not to mention the affects of the metals in the engine becoming hydrides.

Wow, I thought they are storing H2 in metal tanks at 10k psi. Don't you think we should warn them before the metal turns to mush?

[Topher925]

Wow, I thought they are storing H2 in metal tanks at 10k psi. Don't you think we should warn them before the metal turns to mush?

The metal doesn't turn to "mush" the modules of elasticity still remains the same. The material just becomes much more brittle and less ductile.

[RMForbes]

The metal doesn't turn to "mush" the modules of elasticity still remains the same. The material just becomes much more brittle and less ductile.

The engine is already exposed to hydrogen during combustion, adding a little more will not effect any metal parts. To suggest it will is ridiculous.

[mheslep]

Wow, I thought they are storing H2 in metal tanks at 10k psi. Don't you think we should warn them before the metal turns to mush?No they don't. Most tanks are 3K or 5K PSI, with a few 10k PSI tanks coming out now. The higher pressure tanks have sophisticated non metallic liners to prevent H2 permeating into the metal.

See issue on storage and transport of H2 here:
http://www.efcf.com/reports/E08.pdf

[mheslep]

The engine is already exposed to hydrogen during combustion, adding a little more will not effect any metal parts. To suggest it will is ridiculous.I believe you want to check that too. I assume you are referring to some intermediate product of combustion that produces atomic or molecular hydrogen? If that exists at all, the amount of H2 in the piston from the suggested enrichment scheme (10%?) would be many orders or magnitude greater than any trace H2 found in standard hydrocarbon reactants or products.

Also see http://mechanicalplating.com/hydrogen.htm

[RMForbes]

I believe you want to check that too. I assume you are referring to some intermediate product of combustion that produces atomic or molecular hydrogen? If that exists at all, the amount of H2 in the piston from the suggested enrichment scheme (10%?) would be many orders or magnitude greater than any trace H2 found in standard hydrocarbon reactants or products.

Also see http://mechanicalplating.com/hydrogen.htm

Even if the levels needed are that high, which is not the case, all the hydrogen is consumed at the beginning of combustion. There is no chance for hydrogen to react with the metal anywhere.

[mheslep]

Even if the levels needed are that high, which is not the case, all the hydrogen is consumed at the beginning of combustion. There is no chance for hydrogen to react with the metal anywhere.That statement doesn't make any sense. Of course the hydrogen is consumed by combustion, prior to that in a four stroke engine, during both he intake and compression strokes the air-fuel mixture is in contact with the cylinder.
http://media-2.web.britannica.com/eb-media/72/93572-034-26C16785.jpg

[RMForbes]

That statement doesn't make any sense. Of course the hydrogen is consumed by combustion, prior to that in a four stroke engine, during both he intake and compression strokes the air-fuel mixture is in contact with the cylinder.
http://media-2.web.britannica.com/eb-media/72/93572-034-26C16785.jpg

So you are saying that the hydrogen will be able to chemically alter the metal as it flows through the intake at high speed before it combusts. We are talking milli-seconds here, not weeks or months of storage at high pressures.

[mheslep]

So you are saying that the hydrogen will be able to chemically alter the metal as it flows through the intake at high speed before it combusts. We are talking milli-seconds here, not weeks or months of storage at high pressures.The cylinder is exposed to hydrogen roughly half the time the engine is running, regardless of the cycle time, and at high temperature which accelerates embrittlement. I don't think embrittlement qualifies as chemical reaction; apparently (http://en.wikipedia.org/wiki/Hydrogen_embrittlement#Process) the process is due to the formation of molecular hydrogen inside flaws in the metal lattice, worsening them. Since all gas is removed during the evacuation stroke perhaps this slows the diffusion of H into the metal lattice vs the rate seen in a static container, but a same time evacuation cycle is not going to pull all of the atoms back out of the lattice.

No doubt some coating or lubricant can help protect the cylinder on an engine designed for H2, but I think it likely unprepared gasoline engines are likely to see damage with extensive H2 burning.

[RMForbes]

The cylinder is exposed to hydrogen roughly half the time the engine is running, regardless of the cycle time, and at high temperature which accelerates embrittlement. I don't think embrittlement qualifies as chemical reaction; apparently (http://en.wikipedia.org/wiki/Hydrogen_embrittlement#Process) the process is due to the formation of molecular hydrogen inside flaws in the metal lattice, worsening them. Since all gas is removed during the evacuation stroke perhaps this slows the diffusion of H into the metal lattice vs the rate seen in a static container, but a same time evacuation cycle is not going to pull all of the atoms back out of the lattice.

No doubt some coating or lubricant can help protect the cylinder on an engine designed for H2, but I think it likely unprepared gasoline engines are likely to see damage with extensive H2 burning.

Yeah, I saw that Wiki quote before, but I thought you guys were serious scientists. This is obvious bunk. So many errors, where to begin. Hydrogen is not exposed to the cylinder half the time, try less than 25%. There is no left over hydrogen after combustion, not even hiding in the metal lattice. Hydrogen is far too reactive for any not to combust. All gas is not removed during the exhaust stroke, depending on rpm as much as 22% remains. There has never been proof of any hydrogen embrittlement on any ICE running hydrogen enrichment.

[mheslep]

Yeah, I saw that Wiki quote before, but I thought you guys were serious scientists. This is obvious bunk. ... H embrittlement is obvious bunk?
There is no left over hydrogen after combustion, not even hiding in the metal lattice. Hydrogen is far too reactive for any not to combust. You don't know what you are talking about. High vacuum chambers require hours or days depending on the metal to bleed off gas molecules trapped in the metal.

[Topher925]

There has never been proof of any hydrogen embrittlement on any ICE running hydrogen enrichment.

Wtf are you talking about there is tons of proof. During the last energy crisis of the 70s there was a @#$% load of work done on hydrogen enrichment and hydrogen embriddlement was a common failure mode. The crank case and/or liner along with the pistons will be affected by hydrogen embriddlement with standard materials, there is no debate. And the engine is exposed to H2 at least 35% of the time. And FYI, the ignition temp of hydrogen is hell of a lot higher than gasoline, about 250K greater IIRC. Do you even know the stoichy equation of combustion in a gasoline engine with hydrogen enrichment?

[RMForbes]

H embrittlement is obvious bunk?
You don't know what you are talking about. High vacuum chambers require hours or days depending on the metal to bleed off gas molecules trapped in the metal.

I'm sure hydrogen embrittlement exists, but there has never been any evidence that a ICE running hydrogen enhanced fuel suffered any of these effects. It has not even been an issue for experimental engines running hydrogen as the only fuel. And, I did not say all gases are removed from the metal, only that hydrogen reacts too easily to be left over after combustion. Therefore, how can it cause any ill effects. Your theory that engines using hydrogen enrichment will wear poorly because of hydrogen embrittlement, does not hold water. Actually, hydrogen enhancement has been proven to improve engine wear because carbon deposits are not allowed to form in the cylinder. Carbon deposits don't build up on the piston rings to cause uneven wear to the cylinder walls. Deposits in the cylinder are removed so pre-ignition misfires are greatly reduced. The stresses caused by pre-ignition misfires are far more damaging to metal parts than your theory would ever be.

[RMForbes]

Wtf are you talking about there is tons of proof. During the last energy crisis of the 70s there was a @#$% load of work done on hydrogen enrichment and hydrogen embriddlement was a common failure mode. The crank case and/or liner along with the pistons will be affected by hydrogen embriddlement with standard materials, there is no debate. And the engine is exposed to H2 at least 35% of the time. And FYI, the ignition temp of hydrogen is hell of a lot higher than gasoline, about 250K greater IIRC. Do you even know the stoichy equation of combustion in a gasoline engine with hydrogen enrichment?

Calm down and just prove it. Show me one documented case that absolutely proves that the engines failure was due to hydrogen embrittlement only. I don't think you can.