Peter Lynn's Can kites be economically viable (for propelling commercial shipping in mainstream applications)

Baptiste Labat shared this presentation on LinkedIn

Its in French… anyone care to “google translate” the gist of it in english?

Reminding that Skysails and KiteShip have validated ship kites for many years, and they are already economically viable for cultures that put a price on the pollution offset. Peter Lynn has had a close relation with KiteShip (where I met him) and long friendship with Dave Culp, so in a sense, those are Lynn related kites.

The holiday cruise market is not where the major economic shipping AWE action is. Kites have already been used as an entertaining means of moving cruise ships (Old Forum), but the average cruise ship consumers and owners are not so woke as to care much. Electrical cruise ships will similarly be more of a broader trend in overall shipping rather than central leaders in innovation. Many ships are already diesel electric, and merely need ship kites and batteries to go all out.

Right, it makes no sense to me to convert on board mechanical energy from AWE to electrical energy when you want mechanical energy to drive your boat at the end. So let’s add a flywheel to the boat, and batteries for eventualities.

If you’re going to be relying on wind to power your boat I don’t think you can go in a straight line, like you couldn’t in the age of sailing or can now in spaceflight.

Let’s also start from scratch: you want to buy a boat, add and delete some stuff, and then use that to deliver goods or people to another location at a speed and cost that people are willing to pay for, eventually. Your advantage is that you don’t have fuel costs. You rely on software to plot the best course, just like you rely on software to fly your kites.

You can charge your batteries at way-points, you can charge your flywheel at way-points and during sailing.

Let’s assume you’ve built the prototype and it is working. Now you’d like to be able to plot the most efficient routes based on the weather at that moment, the quickest routes, determine the locations of way-points, the size of your batteries and flywheel, your cargo. Ideas for that might come from shipping, sailing, aviation, spaceflight, and weather prediction, for example.

Flywheels: conversion from kite energy to prop thust will have conversion losses. Though I dont have real preferences, it seems earliest possible conversion to electricity and storage in batteries is the simplest and cheapest solution, looking to become a lot cheaper in few years due to electric cars.

Using direct tow is nice, as you get zero conversion. But the tow will mostly be perpendicular to your heading direction so this places severe design constraints on the hull.

Also the point of temporal energy losses. Vessels have huge drag losses related to going at high speeds. If you can go a bit slower in excessive wind but store the energy, that energy could be converted to relatively larger time savings later when you are underpowered.

The one place I see flywheels becoming commonplace is for sail-sport including kites. Reason: it is easy to confirm that a boat did not have with it stored energy at the beginning of a regatta.

Batteries have a limited lifespan and capacity, being also very polluting. An indirect wind propulsion of cargo ships by this means of storage is an illusion. For the rest, the analysis of Peter Lynn (whose link is lost) is largely confirmed. So the reply to the question of this topic is NO.

These things should be documented before stating them as facts. And lets face it, kite driven cargo ships wont be using 2020 battery tech.

I know capacity could be an issue, but mainly related to price IMHO, and price is dropping.

Wrt recharge cycles this article ( states most capacity remaining after 5000 cycles. That should at least be useful for 13-14 years of daily charge cycles. Mind you there must be some excess capacity, putting this number more around 20 yrs…

About pollution:

Quote: « Lithium-Ion batteries are considered landfill safe and were determined by the EPA to be environmentally neutral. Those you heard speaking are woefully misinformed. Over 90% of automotive lead acid batteries worldwide are recycled, and the materials they contain are literally dirt cheap. Traction battery packs for long range electric vehicles are much larger and are composed of far more valuable materials. There will undoubtedly be businesses that will find it worthwhile to Recycle or Reuse them, possibly Repurpose them over time.»

I know things are more complicated than what I’m saying here, but I think there is no concensus that these batteries are very harmful. At least in a 20+ year perspective.

What we do know is that using fossile fuels for this purpose is very harmful, and the effects are not possible to mitigate (except perhaps coupling use with carbon capture and storage).

You’d have to be very careful putting a flywheel energy system in a boat.
It’s moving.
Maybe a solid frame to hold an array of flywheels which are charged with alternate spins to counteract each others torques on being displaced , rotated …
How do the KERS cars cope? Maybe they’re aligned & don’t have to cope with a pitch movement.

The extraction of the rare earth minerals required for batteries constitutes a water disaster in the countries concerned, such as Australia, Bolivia, Argentina, Chile.

Thanks for the comments on the flywheel idea. Another issue with that idea would be the lower energy density of a flywheel. If you take energy density into consideration hydrogen (or methane) pops up again.

Trying to electrify freshwater shipping seems easier.

Some results from a google scholar search on electrifying merchant shipping:

Outdated paper:

Changes in container shipping industry:
Autonomous ship, environmental regulation, and

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No. Apparently you have not read this linked paper carefully enough.

“The lifetime of a battery is measured in discharge cycles (using 100% of a battery’s charge amounts to one full cycle). With a typical 100 kWh lithium-ion battery found in a Tesla Model S providing only 1,000 to 2,000 discharge cycles, current battery tech remains impractical and uneconomical for commercial long-distance drivers.”

“If this patent is revealed to be for the promised “million-mile” battery, we could expect it to hold 95% of its life after 1,000 discharge cycles, where typical Li-Ion’s are in the last quarter of their life. The new battery would hold an impressive 90% after 4,000 cycles (see chart).”.

This is quite different from your statement about what the article indicates.

I agree: do not confuse the reality of the facts with hypothetical promises.

I was thinking a battery that is 90% after 4000 cycles should do 5000 cycles during its lifetime easily. 5000/365=13.7 years. So my calculations were not wrong, like you state.

You are wrong a time more.
I did not state this.

This is not about your calculation, but about the promise the paper indicates after mentioning the fact.

I dont understand. Looking at the graph 4000 cycles should be a quite fair, even conservative estimate for the new battery

I think you need to tell me more exactly why you find something wrong with my referencing this article

The article indicates (I quote again)

This is not 5000 cycles, as you state:

I was talking about the new battery they were developing, that might be available by the time vessel AWE is operational (ie the blue vs the read curve in the plot).

The article mentions a promise for the new battery, not a reality.

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