April 01, 2005
New Fuel Cell Design Avoids Need For Hydrogen Storage
A new highly efficient fuel cell design converts liquid hydrocarbon fuel into hydrogen and then burns it.
"A hydrogen economy is not a perfectly clean system," said Scott A. Barnett, professor of materials science and engineering. "You have to process fossil fuels at a plant to produce hydrogen fuel as well as develop an infrastructure to get that fuel into vehicles. We have bypassed these technological hurdles by basically bringing the hydrogen plant inside and pairing it with a high-temperature fuel cell in one compact unit that has a fuel efficiency of up to 50 percent."
In a paper to be published online today (March 31) by the journal Science, Barnett and graduate student Zhongliang Zhan report the development of a new solid oxide fuel cell, or SOFC, that converts a liquid transportation fuel -- iso-octane, a high-purity compound similar to gasoline -- into hydrogen which is then used by the fuel cell to produce energy. The cells could lead to cost-effective, clean and efficient electrical-power sources for applications ranging from aircraft and homes to cars and trucks.
Although only demonstrated on a small scale, Barnett and Zhan's fuel cells are projected to have a 50 percent fuel efficiency when used in a full-sized fuel cell generator, which would improve on other technologies. Higher fuel efficiencies mean less precious fuel is consumed and less carbon dioxide, a greenhouse-effect gas related to global warming, is produced. Internal combustion engines have a "well-to-wheels" efficiency of a mere 10 to 15 percent. Current hydrogen fuel cells that require hydrogen plants and new infrastructure have been calculated to have a 29 percent fuel efficiency while commercial gas/electric hybrid vehicles already have achieved 32 percent.
"The advent of hybrid vehicles has shaken up the fuel cell community and made researchers rethink hydrogen as a fuel," said Barnett, who drives a Toyota Prius and foresees his new fuel cells being developed for use in battery/SOFC hybrid technology for vehicle propulsion or in auxiliary power units. "We need to look at the solid oxide fuel cell -- the one kind of fuel cell that can work with other fuels beside hydrogen -- as an option."
They use the heat from the fuel cell's operation to catalyze the breaking of the carbon-hydrogen bonds in the liquid hydrocarbon fuel. Smart approach.
Because conventional solid oxide fuel cells operate at such high temperatures (between 600 and 800 degrees Centigrade) Barnett recognized that the heat could be used internally for the chemical process of reforming hydrogen, eliminating the need for hydrogen plants with their relatively low fuel efficiency. Barnett and Zhan found the optimal temperature for their system to be 600 to 800 degrees.
The real key to the new fuel cell is a special thin-film catalyst layer through which the hydrocarbon fuel flows toward the anode. That porous layer, which contains stabilized zirconia and small amounts of the metals ruthenium and cerium, chemically and cleanly converts the fuel to hydrogen.
This approach avoids the need solve all the difficult technical problems that stand in the way use of hydrogen as a form of energy. Even if all the hydrogen distribution and storage problems are solved there would still be the need to build the infrastructure to transport and store hydrogen. This approach avoids the need for massive capital investments to deliver hydrogen to cars.
Also, the use of the fuel cell's own heat to separate the hydrogen probably achieves a larger overall system efficiency than could be achieved if hydrogen was produced in special chemical plants that had to generate their own heat to separate the hydrogen. As long as fossil fuels are the source of the energy used to generate the hydrogen the use of fuel cell heat to convert hydrocarbon fuel to hydrogen will increase overall efficiency. However, if hydrogen could be generated from nuclear or solar power the efficiency advantage of converting from liquid fuel to hydrogen in a vehicle would not be as great.
Another thought: Fuel cells as energy sources in cars will not obsolesce the use of batteries in hybrids. Why? Hybrid vehicles get part of their fuel efficiency boost from regenerative braking. Applying the brakes in a hybrid kicks in an electric generator that uses wheel rotational energy to spin the generator to recharge the batteries. This recaptures some of the energy used to accelerate the vehicle. Even if the internal combustion engine is replaced by fuel cells at some future date a hybrid design would still enable energy recapture when braking to improve fuel mileage.
Batteries may also allow fuel cells to operate more efficiently by reducing the frequency with which fuel cells are activated. Note the high operating temperature mentioned above. In their design that heat is harnessed to generate hydrogen. But every time the fuel cell is turned off waste heat is lost as the fuel cell cools. Some fuel cell designs may even need to be heated up before they can start operating. Plus, there is also the need to generate enough heat initially to use to produce the hydrogen fuel. On shorter trips batteries could avoid the need to use of energy to warm up and run a fuel cell and avoid the energy lost as a fuel cell cools.
1) Where does the carbon in the iso-octane go?
2) Why compare the cell fuel efficiency to internal combustion "well-to-wheel". Compare both "well-to-wheel". (if they did I misread it).
3) How available is iso-octane? Does it require special cleansing to protect the converter?
It looks like a better hydrogen stripper is on the way.
The SOFC is an oxygen-ion concentration cell; the charge carriers are O-- ions, not H+ ions. The function of the fuel is to mop up the oxygen which comes through the electrolyte and gives up its electrons, maintaining the high concentration gradient which produces the cell voltage.
The SOFC doesn't care what consumes the oxygen; it can be hydrogen, carbon, or whatever. It's not fussy about fuel reforming because reforming is not necessary. The only issue is to prevent carbon-based fuels from coking up and clogging the anode with carbon.
Last, the reason the SOFC requires temperatures above 600 C to operate (the first versions ran at about 1000 C) is that the electrolyte is a ceramic which needs heat to allow oxygen ions to move through it.
FWIW, the first note about this in my files regards a Scientific American blurb; the file's date is 1990. These things have been around a while without any mass-market product, which suggests that their problems are not easily solved.
This is real and offers the potential of eventual replacement of the conventional internal combustion engine. The next hurtle is to get the manufacturing cost of this kind of fuel cell engine down such that it can be put into cars. The longer term benefit is that this fuel cell technology can be fueled with synthetic hydrocarbon fuel made from coal, natural gas, or synthesized by nuclear power plants.
Unlike most other proposed "solutions" (hybrids, electrics, etc.), this one offers a real solution.
I'm guessing the carbon comes out as part of carbon dioxide.
Not sure about your efficiency question.
Iso-octane was probably used because using it made that variable simpler. If they'd used commercial gasoline they'd have to wrestle with the effects of various hydrocarbons as well as additives. But to be practical a fuel cell would need to use a more complex mix of hydrocarbons.
I tend toward E-P's view that this latest report is not putting us right around the corner to practical fuel cells. I think they probably have a lot of work to do to make something that is mass manufacturable, with long mean time between failures, and all that.
How well will their fuel cell work with regular gasoline? How hard is it to warm the thing up to 600C? How well does the fuel cell increase and decrease its burn rate? How much less efficient is it when a car is at a stop street and doesn't need as much energy? Will more energy be needed in that case to keep the fuel cell hot enough? How expensive are the metals and ceramic used in this design?
I think the government should be funding a much larger number of battery and fuel cell development efforts because I don't think we can predict how hard it will turn out to be to solve all the problems in each approach.
Kurt's optimism suggests inexperience. Here's a rough sequence line from memory:
1970's: In response to the need to perform closed-loop control of automotive engine mixtures, the zirconia-based Exhaust Gas Oxygen (EGO) sensor is developed.
1990: The first SOFC announcement hits Scientific American; it is based on the same zirconia electrolyte as EGO sensors. Operating temperature is approximately 1000 C to get adequate ion mobility. Construction is solid ceramic, as temperatures are too high for metal. High temperatures create coking problems, ceramic construction does not allow rapid temperature changes.
1999?: Thin ceramic films are found to have adequate ion mobility to operate at lower temperatures, and are much less vulnerable to thermal shock. Coking problems reduced.
(not found): Sintered metal electrodes are found to work with thin-film electrodes at low temperatures.
(The Smithsonian has a history of SOFC's, but it omits details like the tubular cells from a major manufacturer which I clearly recall seeing in the press in the mid-90's.)
These things are evolving, but they're not going to be an overnight fix for anything. On the other hand, at the rate they are improving they will be ideally suited to replace internal-combustion cogenerators by 2015.
I was looking at the long term. I know full well that there is alot of technical hurtles to be overcome before these fuel cells replace combustion engines, not to mention the fact that the car manufacturers will take their time in adopting this technology because they want to make sure that they last 250,000 miles with minimal maintanence.
This technology is the right direction. Fuel cells are efficient because they are not limited by carnot efficiency limitations. The problem is the hydrogen fuel, which is a non-starter. Hydrogen is manufactured from hydrocarbon, anyways. So, the key is to have the hydrogen manufacture integrated with the fuel cell such that the generator/vehicle is powered by hydrocarbon fuel (which can be either natural or synthetic) and the device creates and then utilizes the hydrogen for propulsion or energy generation.
They will initially appear as stationary generators of electricity. The first use of this technology for transportation will probably be railroad locamotives and large trucks.
Thanks to all. I had read about similar processes before but I don't really follow the field closely.
About well-to-wheel efficiency. I meant if the combustion engines is so measured then so should the fuel cell. The article seems to ignore the energy used obtaining and refining the iso-octane. And the losses when the output is sent through motors and gears to wheels.
Then the article tossed hybrids numbers into the mix. It doesn't belong in the discussion of combustion v. fuel cell efficiencies. Hybrids capture energy normally lost off as heat in the brakes.
My point? I'm glad to see progress in hydrogen utilization but the article seemed to throw happy-face numbers without being clear about what they measure.
Like Kurt said, this technique will work for larger installations initially due to size and weight considerations.
This approach will be used for emergency backup electrical systems before it makes it to the small personal vehicle. The market for emergency backup systems is growing quickly and is not just for medical facilities, government facilities, and communications facilities anymore. Large residences for the well to do, and large upscale apartment complexes are starting to install backup systems for when the utilities fail. As prices fall, more and more businesses and residences will install this type of backup.
In the very near term current hybid technology combined with a couple hundred pounds of extra batteries and a smaller gasoline power plant along with an outlet plug could drastically reduce gasoline usage and greenhouse gas emissions, assuming we start replacing coal-fired power plants with nuclear electricity. All without any additional technological advances required. All we need is the car companies to catch a clue. The price of electricity to charge the batteries is far less than the gasoline equivalent in energy. I hope the high gas prices continue (maybe up to $3-4 per gallon) because this will be enough to create a huge demand for this technology for commuters.
If Toshiba's new rapid charging nano-battery is as good as they're claiming then using any form of liquid fuel will be obsolete in the near future. We'll all just plug in at home and use the regular old power grid to charge our cars. We are going to need a lot more powerplants though. Maybe the department of energy should spend more money on fusion research.
Link to the story here.
Matthew Cromer and KirkH,
There is always the question of cost of alternatives.
1) What is the real cost of electricity for new nuclear power plants? Would coal plants that were required to drastically reduce emissions cost more or less than next gen nuclear power plants? I do not know the answer to that question.
2) Will Toshiba's new battery tech cost too much or for some other reason not work well for cars? Keep in mind that existing lithium batteries are not practical for cars (it is my understanding that cost is the major reason). The existing hybrids have nickel metal hydride (NiMH) and I think this is because they are much cheaper than lithium ion equivalents. Anyone know if this is correct?
3) What is the cost of NiMH batteries for existing hybrids? How long do they last? What is the effective price per mile of the batteries for a hybrid using current gen batteries?
I occasionally go digging for numbers to answer some of the above questions. I have not come across authoritative answers for any of these questions. But based on what I have read so far here are my approximate answers to some of the above questions:
1) Nuclear would still cost more than new coal plants that are built to produce an order of magnitude less emissions than current coal plants. Though if coal plants were required to be 99% cleaner or to not emit carbon dioxide then the cost advantage would probably then go to nukes.
2) My understanding is that lithium ion batteries cost too much for use in cars. I doubt Toshiba's new batteries improve any on the cost part of the equation.
3) My understanding is that the hybrid vehicle makers are selling those cars at a loss because the batteries cost so much. But next gen NiMH batteries may last a lot longer and so the battery cost problem is improving.
Another way of looking at this development is to think of iso-octane as an alternative energy carrier to hydrogen or gasoline. It is much cleaner than ordinary gasoline (in terms of sulphur etc.) and is probably made fron natural gas (methane) as that is the cleanest hydrocarbon source. Longer term you could make it and purify it (not cheap) from oil or coal.
Looked at in that way, the proposal is quite odd: iso-octane has a much higher carbon intensity than methane (or methanol) and so is a step backwards in terms of CO2 emissions. The argument presumably is that it is a "step towards a hydrogen economy" - but that has a 20 year lead time whereas this technology will emit CO2 now. Not very clever. Not a good use of energy or cash which could be used to better effect to save energy elsewhere.
Now a fuel-cell that works on methanol or methane would make a lot more sense?
CO2 emissions would be reduced by any technology that allowed cars to use less energy per mile or kilometer driven. I am guessing the researchers are not using the higher carbon content of their fuel to claim higher fuel efficiency.
Boost fuel efficiency 50% and the result would be almost a third reduction in CO2 emissions from vehicles. The reason it wouldn't be a full third is that if the cost of driving per mile was lowered then people would drive more miles. Also, with more efficient power plants available people will buy bigger vehicles, further offsetting some of the gains.
As for making iso-octane from methane: There'd be energy loss at that stage. We really need fuel cells that can burn (either directly or by first converting to hydrogen) conventional gasoline or diesel fuel.
Methane would introduce the need to store a gas under high pressure.
Randall, I'm surprised you went for this. As others point out it isn't sustainable. *Any* hydrocarbon fuel process that extracts and uses the hydrogen has a *big* problem. "What does one do with the carbon?" You might collect it as solid carbon but that sounds like you are going to have to empty your fuel source generator of "lampblack" frequently and that is going to be a very dirty job. The other option are to fuse the carbon to a chemical available (like oxygen) and release it as a gas. That creates big problems for global warming.
The only good sustainable process if you want to use a hydrocarbon fuel carrier is to use the atmosphere as the carbon source. The best way to do that would be in solar ponds that extract atmospheric CO2 and convert it to CH4. If one then wants to convert the CH4 to iso-octane, propane or something along those lines then we should have the technology to do that. Then you get a closed sustainable cycle. CO2 out of the atmosphere, convert to CH4, convert to a useful fuel, burn it, CO2 back into the atmosphere.
The only other way to move towards a hydrogen based system is to split off the hydrogen from water using either a biosystem or even electrical hydrolysis.
But any system that is proposing solutions based on "out of the ground" carbon based energy sources should be viewed with a very raised eyebrow.
Iso-octane is gasoline, as in one of the (desirable) hydrocarbon fractions thereof.
Toshiba's li-ion battery has much higher power density than previous technology allowed. This allows reduction in cost because a smaller (cheaper) battery is required to meet vehicle power requirements; if you need 15 kW for the hybrid assist and your battery is only capable of 2.5 C maximum discharge rate you need a 6 kWh battery, but if you can boost the battery's discharge rate to 10 C you only need a 1.5 kWh battery. The higher the power density, the more you can economize on capacity until you reach the minimum there too.
Again, do not insert carriage returns in your posts.
I went for this because if the technology could be commercialized it would raise efficiency of fuel use. There are obvious economic and environmental arguments for why that is desireable.
Look, we are going to be using hydrocarbon fuels for decades to come. Any technology that can cost effectively improve the efficiency if their use will raise our living standards and make our environment cleaner.
As for artificial carbon cycles: I've repeatedly advocated for their development. photons and electrons could be used to drive fixing of hydrogen to carbon from carbon dioxide. Initially nuclear or solar plants to do this could be built next to coal burning and natural gas burning electric power plants. Eventually we might be able to use wind or solar to drive carbon-hydrogen fixing from the atmosphere.
Are you comparing Toshiba's Li-ion battery to other Li-ion batteries in terms of power density? Any idea what the difference is?
Do you know enough about the particulars of the Toshiba battery in either cost or performance as compared to the currently used NiMH batteries to say whether the Toshiba batteries could cost effectively replace them in hybrid vehicles?
Toshiba's press release does not mention a cost, but does mention several details of performance:
- Charge from 0 to 80% in 1 minute (48 C charge rate at low charge)
- 1000 cycles with only 1% loss of capacity
- Based on the size figures, energy density of about 280 Wh/liter.
It specifies "nano particles", suggesting that it achieves its performance using Altair Nanomaterials' product or something similar.
The press release mentions hybrid vehicles twice and automobiles once. You fill in the blank there.
Re the use of a moderately high carbon fuel & efficiency argument:
The last I heard, a modern diesel internal combustion engine gave a similar well-to-wheels efficiency as a fuel cell system using hydrogen (or whatever) dervied from geological hydrocarbon sources; but at a much lower capital cost (1/100th?). The defect of the diesel option is the particulates local pollution issue, which is generally thought to be OK in Europe and most of the world, but not California.
Yes of course iso-octane is a (the) major constituent of gasoline, but the point is that it has to be really pure for this fuel cell, so it would almost certainly be cheaper to make it from natural gas sources than from oil?
So (answering Randall Parker), I don't think efficiency is the issue here, as they are similar. but the retrograde step of adding more carbon to methane needs a much stronger argument in its favour than the ones I have seen so far.
The number of times the battery can be recharged is very impressive.
I wish they had provided energy in Watt-hours/kg. Sadoway said that lithium polymer would be around 300 Wh/kg. Do you think a liter of lithium ion battery would weigh more or less than a kilogram? According to my less than perfect memory that lead acid batteries are 35 Wh/kg.
In a previous post I excerpted from a PDF file some of Sadoway's claims about what he thinks is possible.
Niels Bohr, the Danish physicist and Nobel Laureate, once cautioned that prediction is always dangerous, especially when it is about the future. With this disclaimer, then, we speculate on what is in store for rechargeable lithium batteries. In the near term, expect the push for all-solid-state, flexible, thin-film batteries to continue. This is driven by the desire to maximize the electrode–electrolyte inter-facial area while minimizing diffusion distances within the electrodes themselves, in order to combine high capacity with high rate capability. Recent results from our laboratory indicate that in a multi-layer configuration comprising an anode of metallic lithium, a solid polymer electrolyte, and a cathode of dense, thin-film vanadium oxide, it is possible to construct a battery with projected values of specific energy exceeding 400 Wh/kg (700 Wh/l) and specific power exceeding 600 W/kg (1000 W/l).10,11 Another trend is distributed power sources as opposed to a single central power supply. This allows for miniaturization (e.g., the microbattery). Expect also the integration of energy generation with energy storage, for example, a multilayer laminate comprising a photo-voltaic charger and a rechargeable battery. Ultimately, if scientific discoveries prove to be scalable and cost-effective, we should witness the large-scale adoption of electric vehicles.
That 700 Wh/l quoted above is 2.5 times higher than the new Toshiba lithium ion battery. But the Toshiba battery is now entering the market and Sadoway's battery research remains so poorly funded that he's now working on a system for replacing coke with electricity in steel mills.
If the Toshiba battery is cheaper than NiMH alternatives then the Toshiba battery could accelerate the move toward hybrid vehicles. But that is a big "if".
Hybrids do not compete against diesel since one could obviously build a hybrid diesel vehicle in order to recapture some of the energy lost in braking (and in order to operate the diesel engine at more optimal RPMs). Also, it is my understanding that the Toyota Prius gets better gasoline mileage than roughly equivalent diesel cars.
2005 Golf TDI is rated at 46 MPG highway; I can't find the equivalent figure for the Prius because Toyota has decided to make their website a craptacular exercise in Flash, but IIRC it's about the same or a bit worse. A diesel hybrid would be quite a bit more expensive but would also achieve considerably better economy.
That might not be necessary. If the goal is to displace petroleum, a greater investment in batteries and methanol production added onto IGCC powerplants may pay off better than diesels while reducing particulate pollution. As always, the optimal solution depends on what you are trying to optimize.
According to the EPA web site the 2004 Prius is rated as 60 mpg city and 51 mpg highway. The regenerative braking combined with lower air friction gives the Prius better city than highway driving. Well, that beats the VW Golf TDI diesel. My guess is that the Prius has more internal room than the Golf too.
The Honda Civic hybrid does 47 mpg city and 48 mpg highway.
Check out the EPA Green Vehicles list. I think that list is sorted by emissions, not MPG.
You are misreading what I said. I was comparing prime movers: fuel cell with diesel. Both can be used in hybrid configuration which obviously improves efficiency in both (with an accompanying increase in capital cost). Hybrid-diesels have the aditional advantage that particulates emissions are lower.
Word is that the EPA mileage figures for hybrids run anomalously high due to quirks in the measurement procedure (which I have never seen explained to my satisfaction, but still).
A parallel hybrid running in city traffic is going to kill any car which has to idle; no surprises there. However, given the systematic errors in the testing the differences are smaller than the EPA figures would suggest, and may even favor the diesel on the highway.
E-P had it right.... this is more accurately thought of as a oxygen fuel cell. hydrogen fuel cells have a membrane that makes a hydrogen give up an electron upon passing through. the SOFC discussed here has a certain amount of oxygen vacancies that allows for useful oxygen diffusion that must also give up charge to pass through. so it is basically a way to 'burn' fuel in a controlled manner that produces electricity directly. Barnett is working on thin film technology because the thinner this SOFC membrane, the less distance the oxygen must travel. high temperature of the SFOC allows for faster diffusion as well, and this can be very localized diffusion.
the reason why i think this is really important practically is because then we can talk about a completely electrical drive system, which means no motor and transmission (finally something that reduces costs). basically an electric car, but instead of recharging, it is filled up with fuel. Depending on the power needs, the battery pack can be reduced because you don't need to blend the mechanical power of the motor with mechanical power from electric motors, you just blend the electric power to four wheel based electric motors - much easier.
this is more useful than hydrogen because storing hydrogen is a huge problem. after all the best way to store hydrogen by volume and mass metrics, is gasoline.
that's "can be localized heating"
I believe that IF we had a reasonably affordable source of hydrogen, then
we can combine the hydrogen with various carbon based compounds to make
high quality liquid fuels, or even liquid propane, which is much easier to
store in compressed form than pure hydrogen.
The hydrogen can be obtained from heating regular water in nuclear reactors, if
we had many affordable nuclear reactors. The future generation breeder reactors
are cost effective, but this is a political issue.
Hydrogen is a huge infrastructure hassle. Even if you tie it to carbon for ease of storage, you've got to either find a cheap, fast, low-energy method of pulling carbon out of the atmosphere or design your entire system around capturing the carbon and returning it to a source of hydrogen for recombination to make more hydrocarbons. It's no wonder that everyone is still assuming the use of fossil carbon.
I'm betting that batteries will improve fast enough to make electricity cheaper than fuel cells in the near future. If you can put 60 kWh of Toshiba batteries into a car, go for 250 miles and recharge them in 15 minutes at a high-power station or in 2 hours at home, what else do you really need?
Even of batteries were ready, by the time the govenment members who are
strongly connected with the oil industry, make any significant policy changes
to encourage nuclear energy production for electric cars, it will be another
40 years (too late). I am not saying that the oil industry agents will kidnap
all the scintists who invent something new, but I am quite sure that the
govenment will do nothing to help new energy sources because of the connections
to the oil industry. Doing nothing is a passive form of sabotage. It was Einstein
who said that if you see the evil an do nothing to prevent it, you are also
Has anyone applied the flow-battery system to transport?
You refuel by pumping in a solution containing V2+/V5+ and offload the V3+/V4+ "waste", whch is recharged at the filling station.
No doubt the energy density of a water solution "fuel" pair is quite low, but if all the designs so far have been for stationery systems, that could change?
Oh look, someone has looked at it: a student project.
A proper economic study comparing this technology with fuel cells would seem to be a useful thing to do. The deployment of the technology is much more robust too - as the "fuel" can be recharged (slowly) at any electrical outlet if there isn't a filling station nearby.
Alternatively a "fuel cell" using zinc and offloading zinc-oxide for re-use would have a better energy density than H2 - the "zinc economy" anyone?
The zinc based fuel cell (one of its competing variants is actually liquid zinc solution that gets loaded and replaced as "charge") is manufactured by Electric Fuel Corp.
Last year they demonstrated an electric bus powered by the zinc-air fuel cell, and this vehicle was competitive with the diesel powered buses. Howevever, to make these popular, we still need a national infrastructure to make these batteries and to make cars that use these batteries (not to mention hunderds of nuclear power plants to charge these batteries... which means that without government support, this cannot take off by itself on time.)
I think electrolye exchange is not practical for the mass market. Exchange stations would be at risk of getting liquid from a vehicle that has been contaminated. Different electrolyte makers would produce liquids of differing quality. The beauty of gasoline is that it flows in only one direction: from gas station to car.
Zinc air batteries may be practical for busses but not for cars. Again, the style of the infrastructure does not lend itself to mass market.
It wouldn't be all that difficult to run things on a zinc economy. Zinc can be reduced either electrically or chemically. We could get enormous amounts of electricity via cogeneration, and the USA is not running short of coal; tapping syngas from an IGCC plant to reduce ZnO to metallic zinc would be a simple and probably cheap way of powering transport from domestic non-petroleum fuel.
Zinc-air batteries are only impractical for cars IF:
- They are primary cells (not rechargeable), and
- They cannot be refilled via methods like slurry hoses.
If you can change either one of those (assuming a reasonable recharge time for #1), zinc-air will do just fine.
One advantage of pure electric cars is that the battery can become standardized in size and weight, so that as better batteries become available in the future, the same old car design would work.
Some versions of the zinc-air batteries offered by Electric Fuel Corp (http://www.electric-fuel.com/ev/index.shtml) are removable batteries that can be replaced at the gas station by a large robotic arm. The depleted battery then gets sent to the recycling factory immediately to be recharged. This method would make it easier to standardize electric cars, which will have an easy design, since a lot less moving parts, and possibly no transmission would be needed, since all the 4 wheels can get an independent cheap motor.
The only issue would then be the source of electricity to charge all these batteirs, but as it was mentinoned above by another commentator, the United States has enough coal for many centuries, although the new coal fired plants must be modern enough to filter most of the heavy metals like mercury (and yes uranium!) in addition to trapping the CO_2.
You don't necessarily need to burn more fuel to reconstitute metallic zinc from oxide; given how much fuel we already burn for various forms of heat, cogeneration could probably handle it easily. This wouldn't eliminate carbon emissions, but would reduce them a great deal.
Zinc is also an excellent storage medium. If you were looking for a way of storing wind or solar power for periods of calm or clouds, you would have trouble finding a better one. You could easily store power on a scale of weeks.
A zinc economy would have some very worthwhile properties. If zinc-powered vehicles could be attached to the grid (perhaps to use their li-ion surge batteries for load-levelling), disruptions of the transmission system might have no visible effect. The vehicles on the power-deficient side would switch to feeding the grid, while the vehicles on the power-surplus side would feed their surge batteries while the zinc refineries got into gear to restore the balance.
Imagine our electric system structured such that terrorists could bomb several long-distance transmission lines at once.... and nothing happens.
To ignore such things is to jeopardize the national security. And guess what Bush is doing....
So our conclusion seems to be that a zinc economy has all the advantages of the hydrogen economy, gets its original power from the same sources (nuclear, coal, wind) and its disadvantages are a strict subset of the hydogen economy disadvantages?
.. with one exception. The existing oil companies like the hydrogen economy because it is in their comfort zone of experience: a simple fuel. It is in everyone elses interest to prefer a zinc economy?
I suspect that the oil companies like a hydrogen economy because they can get a piece of it relatively easily; a zinc economy would throw most of its business to the coal and electric sectors and have nothing to do with them.
"I suspect that the oil companies like a hydrogen economy because they can get a piece of it relatively easily; a zinc economy would throw most of its business to the coal and electric sectors and have nothing to do with them."
Very insightful and very much to the point! The oil company infrastructure can somehow adapt and
profit to the hydrogen economy to some degree if hydrogen becomes the way of the future.
A pure electric system that simply charges all batteries by using nuclear energy, would be deleterious
to the oil industry. And the oi industry is an absolutely gigantic infrastructure all over the world, it
is a state within the state, which makes it a force to be reckoned with.
how does the h2 cyl can be made compact and the same h2 can be used by recyling in the cylinder
trusting fuell cel will provide Hydrogen on line but so far no one advised how much hydrogen requied to heat hot water and house in Europe or North Americ.
Please advise where can I found such engineering details?
Steel tanks provide a safe a reliable way to store hydrogen
The storage system should not be located beneath electric power lines, close to other flammable gases or liquids, or close to public areas.
Only trained and qualified personnel should be allowed to handle