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Power Transportation Science

Football Field-Sized Kite Powers Latest Freighter 251

coondoggie writes to tell us that a new freighter set to launch in December will be receiving a hefty dose of power from a kite the size of a football field. The 460-foot ship, owned by the Beluga shipping company, hopes to see as much as a 50% drop in fuel consumption during optimal conditions. "The SkySails system consists of a towing kite with rope, a launch and recovery system and a control system for the whole operation. The control system acts like the autopitot systems on an aircraft, the company says. Autopilot software sends and receives data about the sail etc to make sure the sail is set at its optimal position. The company also says it provides an optional weather routing system so that ships can sail into optimal wind conditions.The kites typically fly at about 1,000 feet above sea level, thereby tapping winds that can be almost 50% stronger than at the surface. "
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Football Field-Sized Kite Powers Latest Freighter

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  • Optimum conditions (Score:2, Interesting)

    by EmbeddedJanitor ( 597831 ) on Monday November 26, 2007 @05:28PM (#21484247)
    happen maybe 1% of the time? What is more interesting is how the system performs over a whole year.

    Still, good to see that people are trying different ideas.

  • Most of the power? (Score:2, Interesting)

    by JonathanR ( 852748 ) on Monday November 26, 2007 @05:28PM (#21484253)
    So a kite that provides most of the ship's power can only afford a 50% reduction in fuel consumption? Hmmm...
  • Re:Yay old tech (Score:3, Interesting)

    by JonathanR ( 852748 ) on Monday November 26, 2007 @05:34PM (#21484333)
    But No.6/Bunker-C is all the residual shit that can't be used for anything else. It'll get burnt somewhere, somehow. Refiners will find a way to sell it.
  • by Quadraginta ( 902985 ) on Monday November 26, 2007 @05:36PM (#21484379)
    All they need is to have a moderately strong, steady wind that is abaft the beam. Plus good enough weather that they don't risk the kite and its hardware. If you sail the traditional sail-era trade routes the wind is abaft the beam quite a bit more than 50% of the time, the wind is steady at 1000' in the open ocean pretty much always as long as the weather is good, and you can supply your own finagle factor for how often the weather is good.

    Frankly, I think the major limitation on any kind of sail power has been crew cost. Big freighters run with tiny crews these days, and often not very well trained and not especially reliable, except for the top few officers. Getting a crew that can handle a big sail competently, without endangering the cost of the apparatus, sounds expensive. But maybe they've got a robotic, computerized control system that can eliminate that problem.
  • by puppetman ( 131489 ) on Monday November 26, 2007 @05:42PM (#21484439) Homepage
    The original article is here:

    http://hardware.slashdot.org/article.pl?sid=06/07/08/1735227 [slashdot.org]

    The original article claimed a 33% savings in fuel costs. This new article claims a 50% savings under optimal conditions. Interestingly, the greenhouse gas savings are only 10-20%. Where is the logic in that?
  • Or better yet why? (Score:4, Interesting)

    by LWATCDR ( 28044 ) on Monday November 26, 2007 @05:45PM (#21484475) Homepage Journal
    Why put them on the sail. What are the odds that the sail will be pointing at the sun... Why put them on the sail/kite at all instead of the ship? Why risk them getting lost if the sail goes into the water or the cable fails? Why try to make the as flexable as the sail so it is easy to store in case of storm or headwinds? The electrical load of a freighter is actually pretty small compaired to the propulsion load. So are you going to carry a big honking electric motor to use make in to an hybrid? If so why care the extra weight and drag on the screw shaft for something you could only use for a few hours each day?

    Why not? Because it wouldn't really help in any way and would cost a lot of money.
  • by orclevegam ( 940336 ) on Monday November 26, 2007 @05:47PM (#21484493) Journal
    They mention directing the ship into areas that provide better conditions. I wonder if this isn't a tradoff between energy efficiency and shipping time. If the ship re-routes from the optimal path in terms of distance to the one that's longer but provides better weather to reduce fuel, that seems to imply that time is a less important factor than cost. Of course in many cases in which you're shipping things by boat it's the case that time really is less important than cost, as if time was more important you'd be shipping by airplane anyway, but it's still interesting to consider the implications here. Maybe you can get a shipping discount on boats that take the most energy optimal path as opposed to those that take the distance optimal one.
  • by florescent_beige ( 608235 ) on Monday November 26, 2007 @06:00PM (#21484657) Journal

    I just watched their promo video at SkySails [skysails.info]. (The video is here [streamingfarm.tv]). They can point as close as 50 degrees off the wind, so tacking is possible. In other words, if oil went up to $1000 a barrel they could theoretically sail either way across the Atlantic, albeit taking 2 or 3 times as long.

    They show 30% fuel savings, but oil prices have gone up a lot recently, so it might well be closer to 50% now. It launches and recovers automatically and has an automatic control system.

  • It's a washout! (Score:2, Interesting)

    by iamacat ( 583406 ) on Monday November 26, 2007 @06:06PM (#21484721)
    What happens when the kite falls into water and the wind is not enough to lift it up wet? Or worse, what if it falls on top of the ship and hurts sailors, breaks things or rips? It seems we are too hasty to discard centuries of experience in designing sails, masts and lines. Even a spinnaker is at least tied to the top of the mast to keep it from falling and main sails are still useful in head and side winds.
  • by Quadraginta ( 902985 ) on Monday November 26, 2007 @06:10PM (#21484773)
    I don't think it's so important how long it takes for a cargo to get somewhere so much as it's important that it get there when it's scheduled to do so, not earlier and not later. Modern manufacturing, to say nothing of port operations, rail schedules, et cetera, are pretty reliant on things being delivered at a certain hour on a certain day. If a boat happens to come in a day late or something, everything is flung out of synchrony -- you have to pay workers who are doing nothing, because the boat isn't there yet, and you have to hire other guys at overtime rates when the boat does come in, and meanwhile you've missed your rail connection and your factory has run out of raw materials or your showroom has run out of the popular new model of widget...
  • by ACMENEWSLLC ( 940904 ) on Monday November 26, 2007 @06:31PM (#21485089) Homepage
    TCO is often overlooked.

    Take a look at private boats -- sail VS diesel. Sure, sail power is free, right? No. The cost of the sail which wears out, the cost of the lines & riggings. Add it all up and get TCO. Depending on what you are doing, diesel may be cheaper. Especially in commercial applications.

    The cost savings in fuel is offset by the cost in the kite, riggings, and management of the kite. The TCO will be interesting to see. I would be surprised if it was any better than a wash in savings.

  • Furthermore, the kite has upward lift, which helps pull the bow out of the water. This makes it feel less of the effects of waves, smoothing out the ride a bit.

    Unless they put a lot of [heavy] steel stiffening in, the ship will flex at the attachment point rather than lift the bow. Ships aren't rigid.
     
    On top of which, even if the kite were attached at the eyes - you don't want upward force. Upward force doesn't contribute as much to propulsion as lateral force.
  • by TubeSteak ( 669689 ) on Monday November 26, 2007 @06:49PM (#21485263) Journal

    I wonder if this isn't a tradoff between energy efficiency and shipping time.
    Just so everyone has an idea of the time spans involved:

    Pacific Rim* to West Coast USA - 11 to 15 days
    Pacific Rim to East Coast USA - 25 to 50 days
    Europe to East Coast USA - 7 to 14+ days

    The other important routes are Europe to Pacific Rim & Pacific Rim to the Mediterranean.

    Saving 10~50% in fuel costs is no joke when these boats are burning >$20,000 tons of fuel per day. The only businesses that would care about slightly slower shipping are those running Just-In-Time inventory systems and they can either keep paying their existing shipping rate or adjust their systems to compensate for the extra X days of transit.

    *Hong Kong, Russia, India, etc.
  • by necro81 ( 917438 ) on Monday November 26, 2007 @07:09PM (#21485519) Journal

    Thus this 50% efficiency figure seems to me to only apply to one direction of travel. Overall, if one uses the same amount of energy in both direction then that's only a 25% savings. Not bad perhaps.
    I don't know about you, but a 25% gain in efficiency seems pretty good to me. I wouldn't mind being able to get by on 25% less electricity or natural gas at home.

    The real question isn't necessarily the efficiency gain in percentage terms, but whether the fuel savings can offset the cost the kite system. No. 6 fuel (which most ships use) is relatively cheap, because it is one refining step above tar. Seriously, it is really nasty stuff, and doesn't burn cleanly at all. A big cargo ship will go through thousands of gallons of it a day, maybe in just hours. If you can use 25% less fuel in a year, that starts to look like hundreds of thousands of gallons of fuel saved per year, which in turn could mean hundreds of thousands of dollars a year in savings.
  • Related development (Score:4, Interesting)

    by XNormal ( 8617 ) on Monday November 26, 2007 @07:18PM (#21485607) Homepage
    Makani power [makanipower.com] are planning to generate electricity using high altitude kites - at a cost competitive with coal power.

    There's very little information about them for now but they did get a $10M investment from Google. Here [pbs.org] is what Cringely dug up about them from old Usenet posts of one of the team members.
  • by mangu ( 126918 ) on Monday November 26, 2007 @07:23PM (#21485677)
    This new article claims a 50% savings under optimal conditions. Interestingly, the greenhouse gas savings are only 10-20%


    Obviously, conditions aren't always optimal.

  • by Anonymous Coward on Monday November 26, 2007 @07:25PM (#21485691)
    We can fix that: install turbines in the kite to produce electrical power to the ship (it is btw. not my idea, a French or Belgian writer invented this solution back in the 1970'ties) the biggest challenge is making a light, flexible, strong and conductive wire.

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