back to article 'London black cabs to go electric in 2 weeks' – Boris Guardian

Black cabs "capable of zero tail pipe emission operation" will start to appear on the streets of London by the year 2020 under plans announced yesterday by mayor Boris Johnson. Hurry, Boris, hurry! The commitment comes as part of the mayor's new Air Quality Strategy (pdf), aimed at cleaning up various kinds of atmospheric …


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  1. Anonymous Coward

    Solution: VW BLue Motion Polo

    available now. Paint it black and mount "taxi" light.

    1. Anonymous Coward
      Anonymous Coward

      VW Polo

      Black cabs can carry four people with luggage on stop start journeys for over 250,000 miles, a Polo doesn't cut it.

  2. Alan Douglas

    Swappable battery packs?

    I'm impressed to see that the Reg has a clear idea of what technology will be available in 2020 for electric cars. Wonder if it's possible to invent swap-in/out battery packs by then which could be used in a fleet of taxis, to avoid individual taxis having to sit around charging all day?

    Also, what about flying electric cars by 2020, any chance?

    1. GettinSadda
      Thumb Up

      Re: Swappable battery packs?

      Black cabs are one of the few areas where I can see swappable battery packs being a sensible solution.

      For this tech to work you would need a reasonable number of vehicles that regularly need a full recharge, fast, (rather than being OK with a top-up overnight) and where speed is worth paying for. You would also need a massive infrastructure (ideally within a limited area) with staff testing battery packs and even the ability to drive a new pack out to a stranded vehicle if a pack fails for some reason. It would also help considerably if every vehicle in the scheme was of the same design. There would also need to be financial and regulatory reasons to switch to this tech. And finally you really want all involved to be members of some sort of organization that can arbitrate disputes and educate users (maybe even manage financing).

      All in all, I think battery-swap cabs would be a great idea. Especially if charging stations charge off-peak and can give back some power when there are sudden demand peaks.

      1. CaptainHook
        Thumb Up

        Taxi Ranks

        Have the battery mounted under the taxi rather than in it, it pulls up at a taxi rank with an evalated pedestrian loading area.

        Tray slides out from under the pedestrian area to take the old battery out, and put the new one in and stores the battery under the pedestrian area.

        You only need a method of positioning the battery accurately before pushing it back up under the taxi, and that could be done with mechanical guides rather than expensive optical robotics. A 5 minute job.

        Railway stations would be especially good spots for this because they already have the high power electric connections which would be needed for onsite charging.

        No special trips needed for the Taxi, it's just going back to a central location it would probably be going to at some point during the day anyway.

      2. Anonymous Coward
        Thumb Down

        do the math

        "massive infrastructure (ideally within a limited area) "

        You're not kidding. Work out how big a power station you'd need sitting at the end of that "limited area".

      3. Bruno Girin
        Thumb Up

        Re: Re: Swappable battery packs?

        Deploy charging stations at places where you already have a large number of cabs naturally waiting on a regular basis like railway station and airport taxi ranks. Smaller charging stations could also be deployed at major hotels. Of course, you already have part of the infrastructure in the form of existing petrol stations.

        1. Anonymous Coward

          And there was me...

          ...thinking we were heading for a shit-fest of brown-outs and the like since a large proportion of our current power stations were heading for retirement with no viable plan to replace them yet...

          Must've been mistaken, since there's such a push for - as you say - hyoooooge increases in electrickery demands.

          Oh, wait a sec. Maybe I wasn't.

          Joined-up thinking, eh? Gotta love it. Well, the concept, anyway.

      4. Charles Manning

        Redox flow batteries?

        The alternative to switching out the whole battery is a redox flow battery where you just swap out the spent electrolyte and replace it with fresh electrolyte. The spent electrolyte is then recharged for reuse. Down time is no more than filling a car with petrol.

        Way faster and mechanically simpler than swapping out whole batteries.

        1. John Smith 19 Gold badge
          Thumb Up

          @Charles Manning

          "The alternative to switching out the whole battery is a redox flow battery where you just swap out the spent electrolyte and replace it with fresh electrolyte. T"

          Sounds *very* nasty. Multiple tanks, filling/recycling/new electrolyte mfg.


          Side steps the key issue of how do you get the 5 minute fillup for an EV like a combustion fueled car.

          And the fluids will be a *lot* easier to handle than Hydrogen (this is pretty much a given *unless* you like Fluorine or one of the Hydrazine group as one of the reactants)

          This could be last man standing in the battery wars.

    2. Colin Wright


      It's current-ly being trialled for cabs in Japan. If it can't work with cabs it's not going to work anywhere.

      Better Place are doing their swapping thing more generally in Denmark and Israel.

    3. Danny 14 Silver badge


      Wasnt there already titanium batteries that had a 70 odd percent capacity charge in a few mins? Perfect for swap in swap out packs.

  3. Anton Ivanov

    The entire thing is dendent on taxation

    OK, so what will be the guarantee that by 2020 we will not see electricity colouring (hello red diesel) and cars being chipped to ensure they accept only leccy from a "duty-paid" outlet.

    This is trivial - just run a data over power protocol similar to X10 both ways and transmit a challenge/response before opening the "pipe".

    The entire dubious economical benefit of electric vehicles is dependent solely upon taxation. I do not quite see them surviving through being taxed and let me put it this way - with the amount of revenue the crown gets from fuel duty "chipped leccy" future _WILL_ come. It is not a question of "if", it is a question of "when". If leccy vehicles become sufficiently mass market to be taxis by 2020 they will definitely be taxed. HMG initiative to have "smart meters" in every house by that time will happily provide the necessary tax accounting, collection and enforcement.

  4. Paul Hates Handles

    Bet... still costs £20 to go anywhere, thieving bastards.

  5. Anonymous Coward

    Bumper car?

    Suddenly, that joke of the new strategy for leccy cars built by Alpha Romeo doesn't seem far fetched. It would work just as trains. Fully leccy, and unlimited range, if you keep it inside the grid. No worries about batteries either. Actually, it looks like a pretty good idea!

    1. Anonymous Coward

      Would never work

      All those sparks would cause ozone pollution

    2. Robert Heffernan

      Old Idea

      As you can see here, the bumper-car idea was in development since the Mid 1950's, with a prototype even being built.

  6. Tigra 07

    Terrible idea

    The only way to achieve this is with hydrogen, safer than petrol and can be produced for less.

    Plus it gives more range than electric cars and the fuel cells don't cost as much as batteries to replace and won't degrade even half as fast as a battery will on an electric car.

    Hydrogen is already used in Japan for buses with no complaints.

    Electric cars becoming widespread will lead to blackouts, higher electricity costs, and an 8 hour wait to refill your car (and you don't want to do it in the day)

    In the short run, swapping oil for electric means we need more nuclear plants or coal fired ones, more hotels across the country as a long trip is out of the question in an electric car, less petrol stations will be able to stay in business as cars will be there overnight to charge and finally batteries have to be replaced after about 3 years and currently cost £30,000 each.

    So sorry, can't come to work today as i forgot to charge my car.

    1. The First Dave


      "The only way to achieve this is with hydrogen, safer than petrol and can be produced for less."

      Wrong on both counts.

      1. Tigra 07

        RE: Dave Fail


        Hydrogen can be produced through electrolysis in your own garage or from solar panels on the roof of petrol stations, both costing less than peak oil.

        Hydrogen burns upwards quickly while petrol explodes and burns for much longer, while spreading out.

        You don't know what you're talking about Dave, and using the "May contain highly technical information" picture and then offering a rebuttal with no supporting argument is just lazy and a massive fail.

        1. Lee Dowling Silver badge


          Not to butt in on a perfectly good argument but....

          Electrolysis requires electricity, and isn't 100% efficient. So you're actually just running an electric car but with an intermediate step of storage of a highly flammable material under high pressure (you have to pressurise the hydrogen to store any decent amount of it). And if you're doing conventional water electrolysis, you're doing so in the vicinity of huge amounts of highly-oxidising... well... oxygen. Read "explosion waiting to happen". This is why the Hindenburg was a bad idea, by the way - it stored huge amounts of hydrogen.

          And solar panels? Really? You know the ecological impact of them and the amount of power they can *actually* produce and the amount of infrastructure they require to store it for the other 16 hours of the day? You'd be lucky to generate enough for a car journey or two in a car (if you're talking intermediate electrolysis) from a petrol-station sized solar panel, and you'd have more lead, acid, copper and plastic than you would solar panel. All of that has to have had used energy to extract it, refine it, combine it, package it, ship it and replace it. You really are no better off.

          And notice how *everything* comes back to electricity, plastics, semiconductors, rare-earth materials, extremely high precision engineering, transporting heavy stuff to lots of places around the country and constantly repairing it etc. all the time? Don't think fancy methods - think volume. You need the energy to push a car several hundred miles on a tank. That energy, eventually, comes from electricity (e.g. solar). How much impact and time does it take to generate that amount of energy from your method of generation even with 100% efficiency? (e.g. solar = all day, coal-fired power grid = fraction of a second). Now factor in just how many other items are required, just how many transfers (e.g. thermal -> electrical -> chemical -> electrical -> physical) etc. are required, their efficiencies etc.

          Electric cars are *STILL* a nonsense. When we can get a solar panel that can literally power an entire car to run 16 hours a day from a square meter on the top of its roof, then it's worthwhile. Until then, you're just putting "green-looking" steps into an inherently "ungreen" process and ignoring everything else you've done wrong.

          Electric cars are good for milk floats. They were 30 years ago and they didn't *pretend* to be green - they AREN'T - but the tech that drives your modern electric car is actually inherently WORSE in green credentials than a 30-year-old milk float.

          1. Chemist

            "When we can get a solar panel that can literally power an entire car"

            I think peak sunlight is only ~1kW/m^2. So I don't think we will ever see that except for exotic, lightweight cars running in a very sunny climate.

            1. Lee Dowling Silver badge


              Yeah, I know. I wasn't going to mention that. Solar is really a crock.

              But it's the transfers and origins that matter, not what fancy new technology you use. If the energy to run your car comes from solar power originally, then it's quite simple to work out Watts required and how large/efficient a solar panel you'd need to do a single journey. If you assume less than 50% efficiency overall for such things as transfers, conversions, storage losses, etc. then you'll see if it's even *viable* (and that just assumes you *can* get losses down to 50% at all). If doesn't matter if it's via hydrogen, direct electric, compressed air or whether you're synthesising oil, it's the origin of the energy that matters.

              Electric cars work. But somewhere you're burning 80kW worth of coal, or a huge FIELD of wind/wave/solar power at very inefficient ratios rather than 80kW worth of petroleum. I know very well that we don't have much of that left, but until even *one* of the renewables technologies can compete on a real scale (without subsidies, taking its lifespan into account, actual envrionmental cost of setup and maintenance etc.) it's a waste of time and we're just burning coal / oil / gas / uranium in order to make up for the low, unreliable yield of a field full of plastic towers stuck in a hostile environment that are difficult to repair.

              Personally, I just think that petrol cars will get more efficient (efficiency hasn't really been a selling point historically) and then we'll find a slightly different grade of petrol that people can run on in the meantime and that's easier to find (e.g. we'll go back to 90 octane instead of 95/98 or something). People are more likely to own an LPG car in the next ten years than they are an electric car.

  7. Matt 21

    Not a good solution

    The problem is that London is over-crowded. The streets have got too much traffic and the public transport system is hopelessly inadequate. So, of course they decide to build more offices and higher offices to make things worse!

  8. Anonymous Coward

    Re: Hydrogen

    "but hydrogen supplies would be an issue"

    Forgive me if I'm wrong, but doesn't London have a huge river going through it, with 2 tidal surges per day. If the Thames Gateway can generate 128GWh of leccy per hour, why can't they build another, much smaller if necessary that simply sits there cracking water on demand all day long, straight into the tanks of an orderly queue of Taxis? Once the the initial build cost is out of the way, the project is pretty much self sufficient. The water comes from the river, the power to crack it comes from the river, and when the hydrogen is combusted, it turns into more water, that goes via the water cycle, and probably ends up back in the river. Not exactly perpetual motion, but build cost out of the way, the only thing this will need is maintenance to make sure the cogs dont seize up and tanks don't leak.

    1. Anonymous Coward
      Anonymous Coward


      Oops, looks like I might have been read the wrong Wikipedia articles and got slightly fudged generation figures there.

      I can't actually find anything online about hydroelectric power generation on the Thames, bar this article.

      So, doing some simple maths, £1M would buy me 20000 tankfulls of diesel. How much power does 200 homes use up, and could this much power crack enough water on demand to refuel London's Taxis?

    2. Mediocrates

      Hydrogen won't work

      Hydrogen is difficult to work with due to the small size of the molecule -- hard to compress and passes right through materials that can contain other gasses. This leaking hydrogen would not recombine with the oxygen it was originally bound to, resulting in less water on the planet. Plus the whole water --> hydrogen+oxygen --> water fuel cell idea is at best about 60% efficient.

  9. Steve Renouf

    Or..... Joe's cells... anyone?

    Or they could just generate the hydrogen as they need it - a la "Joe's cells"

    or just Google "Joe's cell"

    [url=]Joe's cell[/url]

    1. Danny 14 Silver badge

      The title is required, and must contain letters and/or digits

      wow a cell that works forever, has zero emissions, gets power from atmosphere. They dont have a sarcastic icon on here so i'll let you off.

      I like the testimonials from people who built one themselves, installed it in a truck and were visited by people threatening to kill him if he didnt stop.


    2. Anonymous Coward
      Anonymous Coward


      Just Google "First law of thermodynamics"

      There's also a handy song to help you remember.

  10. This post has been deleted by its author

  11. LuMan

    Size Matters, too!

    I reckon it'll be a good idea to try getting black cabs electrified. Swappable battery packs (see previous) have a number of advantages (and disadvantages) but the feasibility gathers more pace if the actual size of the cabs is reduced. On the odd occasion I go to London I see hundreds of cabs with only 1 or 2 people in them. Hulking great lumps of metal they are too*!! Make them smaller and lighter and the efficiency improves greatly. Make it obvious to the customer whether they're good for 3, 4 or 5 passengers and we may be on to something.

    *The cabs, not the people!

  12. raivn

    Green Taxi

    "They run on nuclear rods that glow green like in the Simpsons. Also this green glow is used to light the inside of the car and the TAXI sign on the roof"

  13. Nigel 11


    From what little I know of the taxi trade, the article seems rather pessimistic.

    Don't taxi drivers spend a significant part of the day parked, either in taxi ranks or taking (legally mandated?) breaks? If these were equipped with fast charging technology, then a taxi could be recharged several times per day, not just once.

    Equipping taxi-only locations with fast charging facilities would be easier than rolling them out to the general motoring population. Similarly battery-swap stations would be easier for a fleet of standardised London taxis.

  14. Anonymous Coward
    Anonymous Coward


    Boris gets something right!

  15. Nigel 11

    Why no mention of CNG

    Why no mention of compressed natural gas? True, it's still a fossil fuel. However, less CO2 emissions than diesel, and extremely clean-burning.

    The barrier with respect to ordinary motorists is whether they be trusted with a high-pressure gas cylinder, and especially with the refilling thereof? That's less of an issue for professional drivers with strong vehicle inspection regimes already in force.

    1. Danny 14 Silver badge
      Thumb Down

      The title is required, and must contain letters and/or digits

      you mean like th LPG pump at the petrol station opposite my works? The one I fill my land cruiser up from?

      1. Anonymous Coward
        Thumb Up

        compressed not liquified

        It takes more energy to liquify a gas that in does to compress it. Your land cruiser can use it too. Lots of buses where I live are using CNG now, and a few using re-newable CNG captured from the rubbish tip. Although cost from that is a bit more expensive because of the extra filtration or something.

      2. Nigel 11

        CNG <> LPG

        LPG is liquid propane gas (could also be low pressure gas). It's not under high pressure, it's not a great hazard, the public can buy cans of it for blowtorches, camping cookers, etc. and in rural areas houses have large tanks of the stuff as their domestic gas supply delivered by even larger tanker lorries.

        CNG is compressed natural gas, ie methane. To store a useful amount in a vehicle means a very high gas pressure.

        1. John Smith 19 Gold badge

          @Nigel 11

          "To store a useful amount in a vehicle means a very high gas pressure."

          If you don't like the pressure of a CNG tank, you're going to hate an H2 tank. The usual figure mentioned is about 5000 psi.

    2. John Smith 19 Gold badge
      Thumb Up

      @Nigel 11

      "Why no mention of compressed natural gas? True, it's still a fossil fuel. However, less CO2 emissions than diesel, and extremely clean-burning."

      Actually it doesn't *have* to be.

      ElReg reported a British Gas funded study that (yes not very likely to be a low priced supplier) that estimated that 50% of the current UK gas supply could be met by anaerobic digestion of putrifiable waste (that's meat, soft fruit, animal slurry. Basically anything not loaded with lots of cellulose and chlorophyll)

      Not quite the warm fuzzy "Carbon free" option Green campaigners love but in *principle* Carbon neutral.

      It might also reduce UK dependence on Russian gas and some of their suppliers more unusual business practices.

      A distinction that might be a bit tricky to explain to Bozzer.

  16. Vulch

    Hybrids could fit

    Extended battery pack for journeys within the congestion zone, switch to fossil fuel outside to recharge and for extra range. Capable of zero tail-pipe emissions, but not always doing so.

    Cab's here, better get my coat.

  17. Anonymous Coward
    Anonymous Coward

    Idle & Plug in Hybrids

    Taxi's spend a lot of time idling, that may improve the outlook for a hybrid.

    Swappable battery packs seem the obvious thing for a large fleet of one-design cars though.

  18. Nigel 11

    Regenerative braking

    Another thing not mentioned is that cars with batteries employ regenerative braking. The greater the amount of start-stop driving, the greater the advantage of this technology, even if it's a hybrid with little electricity storage capacity. London taxis probably do more start-stop than any other sort of motorist. Why don't they take the drive system from a Prius and put it in a taxi? (as a solution that's available now)

    Also in passing - why isn't there a van variant of a Prius? City centre vans are probably nearly as much start-stop as taxis but I'd guess lower annual mileage because more time stopped loading and unloading.

    1. justkyle

      They're working on it...

      Stay tuned for the Prius V...

      We'll probably see it before the Bright Idea from Bright Automotive, even though the Idea looks really cool.

  19. Britt Johnston
    Big Brother

    cheap electricity: nice while it lasts

    Meanwhile, engineers are working on a way to count wheel rotations, in order to back-charge the fuel taxes you saved.

  20. Anonymous Coward

    Zero tail pipe emissions?

    Instead, they will all be combined and sent up a large flue at a powerstation outside London.

  21. Frederic Bloggs

    Do you have a downer on hydrogen fuel cells?

    Isn't it curious that neither the fourth estate nor the politicians that feed them with press releases can be bothered to remember/research stuff on any particular scientific or engineering topic?

    For instance, last week Boris's Deputy Mayor Kit Malthouse launched the first two of eight hydrogen fuel cell buses (which will be used on route RV1). These are not trial buses, they are *production* units. The (much smaller) trial buses have been running on the route for several years.

    Once more fueling infrastructure is in place there seems to be a genuine desire to have more such buses on other routes. And this is 1st Bus's take, not some pie eyed greenery eating surrender monkey.

    It follows that, with a bit creative thinking on the part of TfL, that infrastructure could be used by other transport providers such as licensed taxis. Hopefully before the first lithium battery fire occurs in an electric car.

    1. John Smith 19 Gold badge

      @Frederic Bloggs

      "Do you have a downer on hydrogen fuel cells"

      Depends what you mean by that phrase.

      If you mean a system based on a reformer that takes a *liquid* fuel and turns it into Hydrogen for processing by a fuel cell no. Methanol, Ammonia, even LNG are all good.

      If you're talking about a pure stored Hydrogen system. Yes.

      A few points you may be unaware of regarding Hydrogen.

      Room temp H2 piping is welded (and X-rayed) stainless steel. IE It's *very* expensive relative to normal natural gas piping (plastic or metal). Hydrogen diffuses through metal (or any other kind) walls *very* easily.

      If you want to send it as a liquid you're looking at "Vacuum jacketed" IE *concentric* welded stainless steel lines with a vacuum between. Liquefying it take 1/3 of the energy carried per unit mass of H2 your liquefying.

      So factor in an *extensive* pipe laying operation across London if you want to do this the *proper* way.

      That suggests they will make H2 by catalytic processing of natural gas, a *highly* energy intensive process to produce the "clean" fuel. They will then take a shed load *more* energy either to compress it to a reasonable volume or liquefy it.

      My point is that Hydrogen has a *lot* of problems which make the idea of it as a "drop in" replacement for *any* fuel ridiculous.

      Key point. Hydrogen is an *exceptionally* awkward energy carrier (not a primary fuel. It's only found raw in interplanetary space at a few atoms per m^3) to make, transport and store due to its natural *physical* properties, which don't change unless you live somewhere like Pluto.

      It has *very* poor energy *density*. 1 kg of gasoline gives c62Mj at roughly 1.4l. 1Kg of H2 gives c112Mj at c12.9l (*If* it's at -253c), but as you've spent 1/3 of that to liquefy it in the first place. 20% more energy at only 820% more volume.

      H2 is stored at either -253c (that's *very* cold) or 5000psi or 34.5Mpa (about 345 atmospheres). The USAF issues TNT equivalents on containers pressurised to this level. A bus using this storage method should be good several kilos of TNT.

      No doubt the buses have passed crash testing but at the end of the day we'll know what *really* happens if there is a serious crash. *Hopefully* the tanks will vent and a fountain of H2 will spurt up into the sky and disperse before it ignites (IIRC H2 explodes in air at >4% and <96% H2 concentrations). If not and you're nearby you will see an interesting example of a gas/air explosion. Sometimes referred to as a poor mans atomic bomb.

      James May was very impressed by the LH2 Honda he drove in the US some time ago on Top Gear. The issues he identified are *very* relevant to getting acceptance of non fossil fuel powered vehicles.

      However his grasp of engineering practicality is about about as sound as my grasp of playing a Bach Concerto.

      1. Tigra 07

        Do some research John Smith, proper research, not just Googling

        "It's only found raw in interplanetary space at a few atoms per m^3)"

        Hydrogen is everywhere, it's the most common element in the universe and actually easily extracted.

        Ever wonder what the H is in H2O?

        "Sometimes referred to as a poor mans atomic bomb."

        By who?

        It will burn upwards quickly if it leaks, injuring no one except people standing on top of it, in which case it's better a fuel cell than an exploding petrol tank.

        You can always tell someone who used Wikipedia or Google to make their argument without pointing out a single Pro John Smith

        1. dpg21


          "Ever wonder what the H is in H2O?"

          OK Einstein, how do you get the H out of the H2O? That's right, with electricity! If you need 30% of the energy required to extract the H from the H2O to compress the gas, then a hydrogen fuelled car will be 70% as efficient as a battery car.

          1. Tigra 07

            RE: dpg21

            "then a hydrogen fuelled car will be 70% as efficient as a battery car."

            But it will run almost 3 times as far at a decent speed, rather than at a maximum of 25mph like the electric car.

            Electric cars need expensive, close to £30k batteries to move a third of the distance of a fuel cell, which toyota can make for £15k currently.

            Ever wonder why uptake of electric cars is so poor?

            They cost around £100k for a decent one.

            Toyota, with 15 years+ of research reckons they can currently make fuel cells at £15k, and the whole cars at comparable price to current models with mass production.

            They've got more research into electric and fuel cells than any other manufacturer and they've given up on electric, so argue all you want, but we get hydrogen only vehicles from a few manufacturers between 2014 and 2015 (including BMW, Toyota, Mercedes).

            Oh, and the energy argument doesn't work as we're expected to experience blackouts around 2015.

            How much worse will that be with all electric cars charging everywhere at night?

            They need power plants, which use nuclear energy or fossil fuels, meaning more pollution.

            All electric cars still cause pollution.

        2. John Smith 19 Gold badge

          @tigra 07

          "Hydrogen is everywhere, it's the most common element in the universe"

          Quite true.

          " and actually easily extracted.""

          Not quite true.

          "It's only found raw in interplanetary space at a few atoms per m^3)"

          Please note that word "raw" as in the *elemental* form, H2.

          You don't want a Hydrogen carrying molecule you want *raw* Hydrogen. BTW *all* combustion vehicles already use a mixture of Hydrogen carrier molecules. They call it petrol or gasoline.

          The difference is the amount of *energy* someone is going to put in to get it, multiplied by the amount of energy someone will need to use to process it into a form that can be stored in your vehicle. Even electrolysis is a red herring. Most is still made by processing Methane at on site filling stations. OTOH *directly* usable fuels are *directly* usable.

          Bacteria can make Methane and some (reported in ElReg from a Sulphur belching undersea vent )can make Propane as well. None have been found (or made) to produce Hydrogen.

          I hope that has clarified my views.

  22. Raggs

    Battery tech in 10 years

    Considering the variety of new, promising battery technologies, surely it's possible that some of these will have come through by 2020.

    We have the st. andrews air battery, which they reckon could get upto 10x more storage than current batteries, even 5x would mean ranges of 500+ miles for a lot of vehicles. We have others working on nanotube batteries, which whilst haven't massively increased storage, have recorded much larger power output abilities. So a combo of both could help with frequent start stopping of taxis and the overall distances.

    Charging of course is still potentially an issue, but with official charging stations chucking out power, it should be a far better charging time than we now see.

    Not even touching on the potential for more efficient electric motors (this probably won't get as much improvement as batteries admittedly).

  23. Richard Porter

    Never mind the cabs, Boris,

    (or the Routemaster replacement) - BRING BACK THE TROLLEY BUS!

    Lugging tonnes of lead (or lithium) around the city isn't the answer.

    Electric cabs wouldn't necessarily be plug-in but could use contactless inductive charging at the taxi rank. The problem would be disconnecting and reconnecting every time the queue moved forward. The answer would be to build taxi ranks like nose-in bus stations with an electronic indicator to show the next cab in the queue or a system to call forward the next cab to the pick-up point.

  24. Wize

    What about the occasional crazy trip to Manchester?

    The guy with a big wad of cash and missed his plane/train to somewhere will be told NO by all the battery cabs who wont be able to travel that far and back on one charge.

    Thats the trouble with battery powered cars. Its not a 5minute fill at the fuelling station.

    1. dpg21

      Maybe not 5 minutes yet ....

      But there are commercial chargers already out there that will do it in less then 10. Typical range for an EV at the moment is about 150 miles, double or treble that and get the charge times to below 5 minutes and there'll be no appreciable difference between taking a long journey in an EV vehicle or a petrol one.

      1. Tigra 07

        Fail dpg21

        No electric car can get 150 miles.

        They get half typically at normal driving, and thats assuming you don't stop and start or drive over 25.

        Stop using the same picture every time you post a message dpg21.

        You can't provide any evidence to that last claim.

        Name a single car under £100k that gets 150 miles on a single charge of REAL driving.

        I'll even help you with this. ""

        And notice not a single one under £100k gets over 50 miles per charge.

        And don't forget the batteries in these things are close to £30k IF they're mass produced, if these cars don't sell well the next ones will be in smaller number and cost even more.

        Electric can't compete in any area hydrogen can dpg21, face the facts.

  25. Anonymous Coward

    "zero tail pipe emission "

    I've got a friend with a car that managed that with his petrol car...

    See- not a single tail pipe!

    Two massive side ones, though...

  26. Anonymous Coward
    Anonymous Coward


    The Guadrian have fixed their picture.

  27. Juan Inamillion

    I can see it now

    Outside. Central London. 2 AM

    Punter "Taxi!"

    Cabbie "Where to guv?"

    Punter " Putney please, my good man"

    Cabbie "Sorry guv, I've only got enough battery to get me home to Leytonstone"

    Whirrrrrr...... (into the distance).

    Instead of worrying about what powers the bloody things, perhaps they should take a look at getting rid of all the old really really really uncomfortable ones (you know, the ones that throw you out of the seat when going over a road hump at 3mph). The ones where the heaters don't work, the ones where you break your fingernails trying to lower the window so you can see where you're being taken (usually for a ride).

    Actually, why not just get rid of the stupid Hackney Carriage design altogether and use really really really comfortable, warm, mist-free windows, like with the 'people carriers' you get with the better known private mini-cab companies.

    I was in a black cab recently that had a LCD screen in the back - with adverts playing on it. WTF.

  28. Robert Leeming


    "This means that one will normally need to store the stuff as a cryogenic liquid, which leads to the issue of the liquefied gas boiling off from its tank"

    Surely the hydrogen will be stored as a compressed gas, not below its b.p?

    1. John Smith 19 Gold badge

      @Robert Leeming

      "Surely the hydrogen will be stored as a compressed gas, not below its b.p?"

      *Both* are options. Note Hydrogen has *very* low density (specific gravity relative to water is 0.07 According to Sutton & Biblarz Rocket Propulsion Elements. That is not a typo). Very roughly that's 1/10 the density of a hydrocarbon fuel.

      At standard conditions (0deg C, 1 atm) 2g needs 22.4 litres of space. Applying 1000 atm (14700 psi) will give you 2Kg. Current tank designs run about 5000psi so roughly 600g/l of tank capacity. Compressing Hydrogen is pretty energy intensive.

      LH2 at -253c gives you roughly 1Kg per 14l. Liquefying Hydrogen is quite energy intensive.

      Trying to fill up a GH2 vehicle at a LH2 filling station will not work.

      Isn't it amazing how shifting from a *naturally* liquid to a naturally gaseous fuel shifts your whole perspective on what 's important in a fuel tank?

  29. Dr Dan Holdsworth

    Supercapacitors, anybody?

    The two main problems with electric cars are speed of recharging, and lack of range. Solve the slowness of recharging problem, and as long as charging stations are common enough you've got the lack of range thing solved as well. The only technology that can do this that is vaguely common at the moment is a supercapacitor; you'd need to fit these both in the cars and in the charging stations, to even out the demand at each charging station.

    Oh, and you need a super-powerful source of electricity to run everything; something like a lot of nuclear reactors, for instance.

    1. John Smith 19 Gold badge

      @Dr Dan Holdsworth

      "Solve the slowness of recharging problem, and as long as charging stations are common enough you've got the lack of range thing solved as well. "

      You're right on the charge rate. Supercapacitors can take big chunks of charge quickly.

      However IIRC their issue is that their power density is poor. Basically a lot fewer atoms of a supercap are actually *storing* electrons versus those in a battery.

      At one time NASA looked at using electric motors to move the Shuttle main engines during launch (the current system is a monopropellant turbine driven hydraulic system with a nasty fuel). The last go round of the EAPU project seemed to have gone with a supercap/battery mix to handle the rate and capacity issues.

      I'd check KWh/l and KWh//kg

  30. Aitor 1 Silver badge

    Fuel cells

    Please don't use fuel cells with hydrogen... as it tends to scape earth's atraction, and we will lose atmosphere to space: a very bad idea.

    If pollution is the problem, the solution is very simple: LPG cabs, they pullute like 20 times less than diesels, specially particles (soot). Hybrid LPG taxis would be even better.

    As for the future, electric taxis are clearly the future. With current (this is, in preproduction) batteries, a cab would make 400 miles, and most cabs don't do that in a day. Leave it charging overnight, and everything should be ok.

  31. Andus McCoatover

    Zero tail-pipe emission??

    Damn. That's put paid to a lot of "Greasy Spoon" café's in the Smoke. When I porked out at one near Smithfields - at 05:00 in the morning, my 'greenhouse gases' must've exceeded that of a 50-tonner.

    Majority of the patrons were taxi drivers. ("Gor' blimey, mate, you wouldn't believe 'aw much gas I've 'ad in the back of my cab. 'nuff to blow up the smegging 'indernberg. 'onest, Gov!")

  32. Anonymous Coward

    Johnny cabs?

    Just like in Total Recall.

  33. Antidisestablishmentarianist


    What about the funkin stinkin buses?

  34. Anonymous Coward


    Dash it sah!

    Bring back the rickshaw to this splendant isle!

    That will get the layabouts moving!

  35. Andrew Norton

    Volt's a plug-in?

    last I looked, it was an extended-range hybrid, not a plugin, plus the generator IS enough to run the car when the battery is flat. (the 1.4l engine drives a 74hp genny, meaning it has the same egine size+power as a late 80's volvo 340, but without the RWD fun)

  36. Kevin McMurtrie Silver badge

    Range extension, maybe

    Taxis spend so much time stopped that a tiny diesel generator could keep them going all day. The generator could be either off or running at peak efficiency at all times, so there should be combustion efficiency and emissions improvement with that model. The question is how much all of this weighs compared to simply using a big diesel motor. I'm skeptical of current battery technology available for cars.

  37. Anonymous Coward
    Anonymous Coward

    London Black Cabbies

    "London black cabs to go electric in 2 weeks"

    Well... I suppose it gives the cabbies something to talk about.

    A curious breed. They're kind of like a cross between Magnus Pike and Jade Goody, with an unhealthy dollop of full-fat Duke of Westminster on the side for an added sense of inherent London ownership.

    It's a shame more of them aren't spit-roasted.

    1. Anonymous Coward
      Thumb Up


      You'll have to explain to non British readers who those people are.

      You must take a lot of taxi rides.

      Spot on.

  38. Mark Dowling

    Hybrid taxis

    Seems to me that taxis in a Volt style setup should be able to keep the battery topped up without plug-in while stopped in ranks etc. It is certainly worth subsidising taxis or short hire cars like Zipcar or Autoshare over private cars for hybrid tech since most private cars spend 21 out of 24 hours a day parked.

    As for electric - probably better to look at trolleybuses rather than a set of charging points which would be oversubscribed (like the Boris bike points at railway stations). The overhead wire would be problematic but perhaps Bombardier could be persuaded to adapt their PRIMOVE technology for high-density buses.

  39. Seanmon

    The title is required, and must contain letters and/or digits.

    Taxis in an urban environment is about the only place I can realistically see electric cars working. One lot up here in the Weej are having some success already.

  40. scatter

    Cabs are ideally suited to being pure EVs

    Daily mileage of a central London cab is unlikely to exceed 150 miles (9 hours is the maximum you can drive for in a day and average traffic speed in London is about 15mph if I remember right) which is an eminently achievable range. And it's a very stop start drive cycle - perfect for EVs.

  41. Anonymous Coward

    A great step forward, but.....

    When can we expect police boxes that are larger inside than they are outside?

    Mines the one with the 12 foot long multicolored scarf...

  42. John Smith 19 Gold badge

    Kinetic batteries anyone?

    That's a high speed flywheel (usually magnetically suspended in a vacuum) with integral solid state motor/generator system.

    Potentially fast charging, slower releasing high power density and as long as the vacuum stays intact good long term storage (no gradual loss of capacity as *all* battery systems seem to have).

    You still need to generate the power in the first place but that's a given for *any* option.

  43. Mips
    Jobs Halo


    Your comments are just much semantic bollocks. Any improvemnt is better than none.

    When leaving Charring Cross to cross to the north side of Trafalgar Square I took to the practice of holding my breath to cross the road. Apart from the risk of getting knocked down (mostly by cyclist as nothing else was moving) the choice was of passing out or getting poisoned by the toxic cloud. I wasn't just the taxis I think the buses were worse.

  44. Tigra 07

    The title is NOT required

    Hydrogen range is easily triple electric range, without the load of batteries filling the boot.

    Pro Electric campaigners always use the same arguments against hydrogen power:

    1) It's dangerous. Name a single death from hydrogen and i can name even more from electric.

    2) It's impractical. Then why do Toyota state that electric is not a permanent solution compared to hydrogen?

    I'll take Toyotas word over anyone elses here because they can actually offer proof and have over 15 years of research in both electric and hydrogen transport.

    1. Andus McCoatover

      1) It's dangerous. Name a single death from hydrogen and i can name even more from electric.

      1) Hindenberg.

      2) My missus's 'cooking experiments'.

      As to 2), the police are looking for the Oulu Serial Gasser. Best I piss off, she's approaching.

      OK, I'll give you the last phrase.

      "Old Sparky" might top the chart on that one.

      1. Tigra 07
        Thumb Down

        RE: Andus

        It's widely known that the deaths on the hindenberg were caused by "A" jumping from the hindenberg, and "B" it crashing.

        Only a small handful of people sustained burns and they weren't considered life threatening.

        The skin on the hindenberg created static and lit the hydrogen, which dissipated quickly.

        As for your wife's cooking, thats between you and your smoke alarm.

    2. John Smith 19 Gold badge

      @Tigra 07

      "Hydrogen range is easily triple electric range, without the load of batteries filling the boot."

      Well that's a pretty definitive statement.


  45. Adam Nealis

    Run them on water.

    Or at least a combination of water and petrol.

    This is not perpetual motion, by the way.

    1. Anonymous Coward
      Anonymous Coward


      Don't believe all you read on the internet !

      This is nonsense !

    2. Francis Boyle

      Yes it is

      Just with extra obfuscation (and possibly self-deception).

  46. dpg21

    Don't need to swap the batteries people.

    The technology already exists to fast-charge automotive batteries. Current technology batteries can be charged to 80% capacity in less than 10 minutes. Here's a link for the unbelievers:

    1. Tigra 07

      RE: dpg21

      The ones for your house cost £3k when i last looked and weren't that efficient, so industrial ones for petrol stations are likely closer to £40k.

      And with the cars costing so much and being so rare, noone will buy these things.

      And don't forget to mention that the £30k batteries in these things degrade quickly after 3 years, or less if you don't treat them right.

      You used the same tactic everywhere here dpg21, by Googling your evidence for your argument.

      Look up hydrogen vehicle stats, and look up electric.

      Electric needs a breakthrough on cost, infrastructure, more efficient batteries, smaller batteries, power supply.

      Hydrogen needs only infrastructure according to several manufacturers, including Toyota.

      And countries are already building it, so hydrogen cars will storm the markets, while electric cars are still too expensive and useless for anything other than milk floats.

      Do your research dpg21

  47. kingosticks

    The London Electrical Cab Company

    I'm really surprised there is no mention of the London Electrical Cab Company. Electric taxis have been done before, complete with swappable batteries. The technology has changed somewhat since then but batteries are still heavy and the whole thing requires a decent infrastructure. Depending on what history you read they were not a complete disaster - oil companies got their act together but electricity companies didn't. There are a bunch of really interesting accounts about it all but searching now I can't find anything good.

  48. John Smith 19 Gold badge
    Thumb Up

    London cab battery packs could be the DRAMs of the 2nd decade.

    Standard size, so level(ish) playing field.

    More capacity, faster charge, lighter weight -> economic advantage.

    Operators prepared to pay *for* economic advantage.

    Enough players and enough market to make incremental innovation (still compatible iwth charging infrastructure) worthwhile.

    OK chances are it will go nowhere, but a guy can dream, can't he?

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