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This discussion relates to Technology Review's article Next Stop: Ultracapacitor Buses.

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  ecodelta
  

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  10/19/2009 01:48 AM

  use small generator

  One solution for lower range with Air conditioning would be to use a small power generator to power it, maybe even battety or capacitor assisted.

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    cenesdelavega
    

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    10/20/2009 06:27 AM

    Re: use small generator

    Or better yet, use existing diesel hybrids, (for example the Daimler/BAE serial hybrid) install in-pavement inductive charging stations along the route, thereby converting them into "plug-in" hybrids. This way, the buses become almost all-electric, but with the security of the diesel backup. Contact me at www.opbrid.com for details.

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  ryuuguu
  

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  10/19/2009 05:45 AM

  US not good market for this

  US is not a good market for this.  In greater Tokyo there are lots bus routes where the speed limits on the roads is 40kph~50kph and the bus stops are close together.

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    Kevin Bullis
    

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    10/19/2009 04:59 PM

    Re: US not good market for this

    Note: The original version of this story said that the bus is limited to 30 miles miles per hour. That's true of the ultracapacitor bus in Shanghai, because that's the speed limit there.  But the buses can go much faster--up to 80 mph if necessary, according to the company.

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  erbium
  

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  10/19/2009 05:48 AM

  even less energy?

  batteries hold something like 1/100th to 1/200th the energy of chemical fuels
  
  this holds 5% or 1/20 the energy of batteries.
  so overall capacitors hold the energy equivalent of 1/100 * 20 = 1/2000 the energy of chemical fuels?
  
  might as well have hamsters running in a fly wheel inside the bus.  scale this up to capybaras (giant rodents from the Amazon) on a larger wheel.   Feed them some renewable grains and voila!  an eco-friendly bus energy source with at least as much power.  have a 5cents - feed the capybara - recharging station at each bus stop.
  
  I'm all for renewable power sources or sources that can have power fed from the grid, which can be converted to renewable over time.  And it looks like capacitors have a place with their quick discharge, but this looks lame.
  
  BTW, I've seen those declare lithium ion batteries 'safe'.   or safer than gasoline or hydrogen.  On an solar electric car race documentary (on discovery channel) they mentioned that lithium ion batteries, when they catch fire (and appears they can catch fire instead of exploding like Sony laptops or exploding Apples) they burn at 2500o, pretty much unstoppably melting a hole in the concrete below them similar to thermite. 

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    gabrielg01
    

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    10/19/2009 03:11 PM

    Re: even less energy?

    We could place bike pedals at every passenger seat, and then the passengers would collectively run the bus. Americans are obese anyway, so it won't hurt to exercise.

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    peter.mcmahan
    

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    10/19/2009 09:40 PM

    Re: even less energy?

    batteries hold something like 1/100th to 1/200th the energy of chemical fuels
    
    this holds 5% or 1/20 the energy of batteries.
    
    what's your measure? volume? weight? I don't think your comparison is relevant. The whole point is that these buses don't need to store a whole lot of energy -- just enough to get them to the next stop. If the stops are less than a mile apart, it should be simple to store enough energy on board, even at a tiny fraction of the energy density.

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    mkogrady
    

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    10/20/2009 08:51 AM

    Re: even less energy?

    Yes - a mouse powered bus makes sense until you realize the rat turds would cause Hantivirus outbreaks, make people sick and die and then the rider frequency drops off to the point the route is no longer economically feasible. The bus company goes belly up and we're back to walking, riding bikes or taking another form of transportation.

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  jarauz
  

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  10/19/2009 06:23 AM

  Technology has been in use for several years already

  Urban trains in Mannheim and others have been using it for about 3 years already.  Check:
  
  http://electronicdesign.com/Articles/Index.cfm?AD=1&ArticleID=17465&pg=2
  
  for more information.

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    chrisjmiller
    

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    10/19/2009 07:53 AM

    Re: Technology has been in use for several years already

    According to that link, the Mannheim system is used to capture energy from braking and hence improve efficiency - it's not the sole means of energy supply.  On the other hand, haven't Gyrobuses used the same principle (with flywheels instead of ultracaps) since the 1950s?

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    • 
      flywheelsRbetR
      

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      10/19/2009 12:57 PM

      Re: Technology has been in use for several years already

      hopefully flywheels will begin to emerge in the USA as the preferred technology to L-Ion batteries and capacitors... capacitors are very unstable and there isn't enough lithium in the world to sustain fully electric vehicles.
      
      Hopefully we will be able to secure funding and complete our work and make this world a much better place by drastically reducing our need for fossil fuel.   

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      • 
        erbium
        

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        10/19/2009 10:16 PM

        Not enuf lithium in the world

        supposedly there is only a '10 year supply' of lithium at industrial sites ready to be mined.
        
        The problem with that is there is only a '10 year supply' because when you have 10 years supply you don't go looking for more!
        
        the history of oil and many other natural resources is exactly the same.  For many years (around 100) there has been 'about 10 years left' of oil.   It is just now that we are rounding the peak of oil and the reserves (easy to get to ones) are REALLY running out.
        
        Bolivia for example has vast reserves of lithium, undeveloped, in salt lakes.  Admittedly unstable country, perhaps the peasants would be 'less revolting' if they got a mine to employ them.
        
        Other countries similarly have undeveloped reserves and are spending billions to develop them.  Lithium power sources will NOT replace all other energy storage systems.  However they will be a BIG PART likely of any future energy supply chains for transportation and other uses.
        
        BTW, lithium batteries can be more dangerous than gasoline.  Exploding in laptops, incidents from sony and apple show this, and burn at 2,500degrees, which is quite hot for a fire, and will burn a hole thru concrete.  A solar car racer burned alive in a lithium battery car fire and this was mentioned on show documenting solar car race.

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