Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Hydrogen car lunacy.

  1. Apr 22, 2008 #1
    I have seen some 'stuff' saying hydogen is the way forward in term of pollution,
    however, whils the cars themselves may not polute, in terms of CO2, I would
    bet a sizeable amount that the energy required to produce the hydrogen produces
    as much, if not more pollution, than if the cars ran on gasoline.
     
  2. jcsd
  3. Apr 23, 2008 #2

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Hydrogen is an energy carrier that allows alternative forms of energy such as wind, solar, geothermal and nuclear power, and biomass, to be used as a pollution-free energy supply for the transportation sector. But hydrogen is only an energy carrier and not an energy source in the same way that petroleum is today. So you are correct: We need to solve the source problem in order for a hydrogen economy to be practical.

    BTW, this is day one of Hydrogen 101. The people who are serious about moving to a hydrogen economy understand all of this.

    Right now Iceland has begun to convert entirely to hydrogen, but they have plenty of geothermal power.

    There are processes that can produce hydrogen as a byproduct, and we need to address the practical aspects of hydrogen storage and distribution, so it probably makes sense to explore the practical application of hydrogen technologies on a limited basis, for now.
     
    Last edited: Apr 23, 2008
  4. Apr 23, 2008 #3
    Most new ideas and innovations have a multitude of problems. Think back to when the first combustion engine was introduced. It must have been the most uneconomical piece of machinary ever, not to think about the early gasoline refinaries and the pollution they generated. But life today is unthinkable without it. I think hydrogen is not a BAD idea but rather a NEW one, that can be refined to levels beyond our imagination. Think how batteries has evolved in the last ten years due to cell phones, give new ideas a chance. I can imagine the critisism Leonardo Davinci got when he planned the first helicopter, maybe if he had more support and achieved flight back in the day, our lives would be much different.
     
  5. Apr 23, 2008 #4
    I have a hard time seeing what advantage hydrogen has over batteries for vehicles. :confused:
     
  6. Apr 23, 2008 #5

    Integral

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    As well as being heavy, batteries are chemical nightmares. They have a limited life and at the end of that life must be disposed of, at which time they become very UNgreen. Currently they are just one more example of "feel good green".
     
  7. Apr 23, 2008 #6
    But battery car avoids the main problems that hydrogen has. There is already a distribution grid and batteries seems to become better quickly. Plus the overall efficiency of batteries are much better than hydrogen.

    Hydrogen seems to have alot more obstacles to overcome, while batteries "only" need to get lighter and cleaner.
     
  8. Apr 23, 2008 #7

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    And greener to make and recycle and able to be completely re-charged at a filling station in a couple of minutes. One of the big advantages of hydrogen is that you can use the existing infrastructure of gas stations.

    Of course hydrogen has a few technical problems of it's own !
     
  9. Apr 23, 2008 #8
    Go H2 Go

    If the only problem of distribution is money ... Then this is a non-problem.

    ( how much is spent on weapons per year? ) Ha ... I think I can find the money.
     
  10. Apr 23, 2008 #9

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    The main 'advantage' of hydrogen and biofuel is that they fit the current business model of large production companies and existing infrastructure of refineries/tankers/gas stations.
    The problem with batteries is that people will think and plan short trips around the city and might consider public transport instead. It also means the oil companies shut down and the power companies become all powerfull - unlikely to happen!
     
  11. Apr 23, 2008 #10
    Um batteries need to be charged and, unless i am mistaken, most electricity is still produced through the burning of fossil fuels. So, using batteries does not eliminate the carbon footprint that automobiles produce, it might reduce it, and re-distribute it... but there will be a greater demand for electricity, and again, unless i am mistaken, that is already a problem. Whereas we cannot say how we will produce a viable amount of hydrogen.
     
  12. Apr 23, 2008 #11

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Hydrogen is just a battery alternative - both require you to generate the energy somewhere and use it in the car.
    It's simply a question of which offers the most convenience in a car (size, power density, refilling time) and wether it it easier to transmit electricity long distances from cheap sources of power or transport hydrogen.
    The advantages of either is that you can generate electricity efficently in large facilities and have less pollution concentrated in cities. It's the reason we have grid electricity to our homes and offices instead of individual gasoline generators on the sidewalk.
     
  13. Apr 23, 2008 #12
    Well, I don't think that can be argued effectively without the technology being researched further, we don't have hydrogen being mass produced for this purpose, and for that matter, with respect to the replacement of all IC engines, we don't mass produce the required batteries.
    As for distribution of power, we could have battery stations in the same way we have Petrol stations, but instead of charging a battery, you just swap it with a charged one, that the battery station collects (or gets delivered) from a central source. Carrying on your explanation of Grid power vs. Sidewalk generators.

    Although i think i would say that coal fired power stations may be more efficient than a portable petroleum generator. But this is not more than hopeful supposition.
     
  14. Apr 23, 2008 #13
    That sounds so dismissive !?? Just a battery alternative ? :(

    Alternative is the word of preference I promote. Enough of 'stay the course', time to adapt.
     
  15. Apr 23, 2008 #14

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    >Alfi
    An electrico-chemical battery, hydrogen, a fly wheel or even a tank of compressed air are all just energy storage systems - rather than fuelled engines. Which you use is just a an engineering question.

    >linton
    We could have battery swap outs - but without a MAJOR change in battery technology the batteries are going to be large and heavy enough to be a major structural part of the vehicle. Certainly requiring some sort of powered machine to swap them, you aren't going to pop-out a laptop size unit at the gas station and get a new one from a vending machine. There is also going to be an issue of all vehicles (from a smart car to a Ford F350) taking the same size/shape of battery and mounting it in such a way that it can be accessed with the same machine quickly and easily.
    There are also issues of the value of the battey being much greater than the value of the power it stores and th elimited life. None of these are impossible, some of them are solved for LPG cylinder sales for example.

    I suspect there will be multiple solutions:
    Plug-in small electric Smart cars for city commuting, recharged at parking spots.
    Hydrogen for larger family / performance cars with fuel stations on highways.
    Biodiesel for heavy commercial vehicles.

    And hopefully a few more bicycles ;-)
     
  16. Apr 23, 2008 #15

    LURCH

    User Avatar
    Science Advisor

    Right now there is a capacitor being developed at MIT (with help from Ford Motor Company) that could replace batteries. It wuold store as much electrical energy as a Lithium-Ion Battery of the same size and weight, but because it is a capacitor, it would charge quick and last longer than the vehicle. If and when this gets developed and mass-produced, the electric car will become a viable technology. I just I don't think batteries are ever going to be a reasonable alternative for powering vehicles, for the reasons already stated.

    But this cap would be made to the same dimensions as the batteries currently used in hybrids. I'm hoping plug-in hybrids become common just about the time the cap makes it to market. Owners who are dissalussioned at the end of the service-life of their first battery could replace it with the cap, and suddenly find themselves in possession of a storage device that they will never need to replace, that isn't effected by cold weather, and (if they have a high-current outlet available) can be fully charged in an hour or so.

    Then, service stations (seeing a chance at a profit) will start putting in a "plug" in addition to their pumps. This would be an ultra-high Wattage source (the kind you can't get in a residence) that can charge a cap in a cuople of minutes. They would charge a little more per KWhr than they are paying the utility, which comes to an equivalent of about $1/gal, and their customer traffic would increase. Soon, drivers with plug-in hybrids will start arranging their daily drives so that they can get to the staion before the charge runs out and the IC engnie comes on, and any station that wants to stay in business will have to have a plug.

    As I see it, this is the most likely scenario for switching to electric. Not perfectly green, but I've run the numbers and its less than half the CO2 of gasoline.
     
    Last edited: Apr 23, 2008
  17. Apr 23, 2008 #16

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Even with supercaps replacing batteries it's still tricky to quickly charge a car.
    Gas/petrol stores around 35MJ/litre - so a typical 10gal fuel tank = 1.75 GJ
    You can refill this tank in a couple of mins - pouring gas at 0.5L/s is equivalent to transferring 20MW of power. Even if super caps could absorb this rate it's going to take some fairly chunky jump leads at the gas station.

    Supercaps also have issues of high leakage rates and low breakdown voltages - they are probably best used for 'buffer memory' storage in a regenerative braking system to avoid shallow charging/discharge cycles on the main battery. I imagine 'turn off while idle' and regenerative breaking electric startup/slow speed will become standard in the next 10years - certainly in small in-town cars.
     
    Last edited: Apr 23, 2008
  18. Apr 23, 2008 #17

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Actually, there's not. We would have to effectively build another one [double the existing capacity or more] in order to supply and carry the power that would be required. As it is we have areas that experience brown-outs and temporary black-outs during periods of high demand on the grid, so we can barely keep up now.

    Based on the current energy demand, it would probably require 200 years to build enough nuclear plants to power a nation of electric cars, and that assumes a dedicated national effort and that its even possible politically!
     
    Last edited: Apr 23, 2008
  19. Apr 23, 2008 #18
    Oh dear virtually every body seems to have missed the main point that fossil fuel is required to make hydrogen and charge batteries. - Ah well dream on.
     
  20. Apr 23, 2008 #19

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    No we haven't. Although the problem is the same for either battery/hydrogen - using either technology gives you some advantages.

    You get to generate 'energy' in bulk in a more efficent plant. Which ideally would be nuclear.

    Even with fossil fuels you isolate the pollution in a single source where you can fit smokestacks/scrubbers to reduce the effect rather than spread it around a city at ankle height.

    You can generate the hydrogen where power is cheap and ship the 'energy' to the customer even where the distance makes a power line impractical eg. Iceland=geothermal, Middle east=solar, Canada=hydro.

    As I said before - if large scale power generation and distribution is so much less efficent than gasoline, why don't we all have 3rd-world Honda generators outside out houses!
     
  21. Apr 23, 2008 #20

    Ivan Seeking

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    People do understand this. You should read what has been posted.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Hydrogen car lunacy.
  1. Stop biofuel lunacy (Replies: 108)

Loading...