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      Abbreviated rules   07/28/2017

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vibroman

FP Teslaof the seas?

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All electric autonomous container ships?

really? How does that work given that a containership needs many 10's of thousands of horsepower over extended periods of time to operate? Currently we are stuggling to get a 2 tonne vehicle to travel more than 300 miles? Report seemed to reference small vessels not the big uns. Gonna need a helluva battery bank.

 

 

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It will probably soon be feasible to make a collision avoidance system for boats for open water use. Definitely enough by way of sensors to connect to autopilot systems. A back-up assist for docking would be great!

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1 hour ago, Bcubed said:

Likely a hybrid system, diesel-electric or turbine electric like locomotives.

These systems have been used on ships and boats for at least 70 years or so, so not really a new idea.

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Also significantly more complex and therefore less reliable than a simple electric motor.

The advantage of the electric drive in autonomous applications is its reliability. Without reliability hard to be autonomous.

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Autonomous robotic mechanics will have that fixed right up for you! 

     Something that Rolls Royce has been making big progress on is monitoring those electric motors in the drive pods on ships. They can predict well in advance from vibrations and input/output curves when a motor will need service and can do that long before something breaks down. I would think that a small gas turbine generating the electricity for electric drives could go many months in an autonomous vessel.

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10 hours ago, vibroman said:

All electric autonomous container ships?

really? How does that work given that a containership needs many 10's of thousands of horsepower over extended periods of time to operate? Currently we are stuggling to get a 2 tonne vehicle to travel more than 300 miles? Report seemed to reference small vessels not the big uns. Gonna need a helluva battery bank.

Do you have a link? The reporter may have screwed this one up ... a container ship needs something like 50,000 kW to keep it moving at a functional hull speed. So about 17,000 Mwh of energy for the trip from China to Los Angeles. A 1 MWh battery bank fits in a 40 foot container, and runs about $0.5 million in quantity.  So they would need to spend over $6 billion in batteries to power each container ship, and most, if not all of the capacity of the ship would be spent on batteries, leaving little to no room to actually haul anything. It would take at least two weeks to charge up such a ridiculous battery bank, and if they scaled it down to small ships, it would still take a large portion of the cargo capacity to store the batteries. Diesel and bunker oil have something like 50x to 65x the energy density of batteries. So multiply the size and weight of the oil or diesel fuel tank times at least 50 to get an idea of the battery bank requirements.

They probably mean that it's a diesel-electric or oil-electric, like what Rasputin and Kent mentioned, which is dead common for container ships, and maybe the novelty is that it's autonomous. But what does that accomplish? It saves the job of maybe three or four crew? You still need all the regular crew for maintenance, shore communication, and the regulation crew. Seems a silly idea. I get it when the cargo of the autonomous vehicle is a single bar patron in a Lyft coming home while shitfaced, yeah, an autonomous drunk-cab might be efficient. But there doesn't seem a lot of upside with a few hundred million dollars of cargo to skimp on a few salaries.

Yeah, the Navy might find that it improves their safety record.

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1 hour ago, Rasputin22 said:

Autonomous robotic mechanics will have that fixed right up for you! 

     Something that Rolls Royce has been making big progress on is monitoring those electric motors in the drive pods on ships. They can predict well in advance from vibrations and input/output curves when a motor will need service and can do that long before something breaks down. I would think that a small gas turbine generating the electricity for electric drives could go many months in an autonomous vessel.

Rasp

The motor is the easy part, and yes Vibration Analysis is one of several tools we use to assess the condition of the machine.

The diesels / gas turbines add a significant amount of complexity and therefore potential un reliability to the system so although you can monitor it remotely for changes in condition, even with the best CM tools failures can arise be detected and cause functional failures withing the typical passage time of such vessels. End result you will need someone to fix it when it breaks. Now eliminating the Naviguessers thats another story. We were telling them that 40 years ago!! Trouble was apparently this new thing called GPS by magnavox was not to be trusted;-). In fact we put a ship on Admiral Sterlinggraff (sp) reef in the S china sea back in the day because they would rather believe a hazy noon sight over the Magnavox !

Mike

I was refering to a piece from the mythical FP which said all electric container ships. Which clearly are not feasible This is why I started the thread.

 

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On 9/13/2017 at 5:46 PM, vibroman said:

 

I was refering to a piece from the mythical FP which said all electric container ships. Which clearly are not feasible This is why I started the thread.

FP? I'm not sure that exists, it isn't feasible.

All-electric container ships, agree, not feasible with batteries. But hydrogen or someday capacitors, maybe.

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51 minutes ago, mikewof said:

FP? I'm not sure that exists, it isn't feasible.

All-electric container ships, agree, not feasible with batteries. But hydrogen or someday capacitors, maybe.

Mike, is there any way to make the hydrogen that doesn't consume more power than it provides, or at least has no more loss than using electricity to charge a battery?  Sure, hydrogen burns clean, and it has a pretty good energy density, but until we get clean electric power aren't we just moving the pollution from one place to another?

And capacitors?  Current technology gives about 50 Wh/liter stored energy density.  Compare that to 10,000 Wh/liter for diesel fuel.  Is there any realistic possibility that the capacitor energy density can be improved 200X?  Or even 20X?  At some point, the cost savings of paying for recharge electricity (vs burning diesel fuel) will tip the scale, but you need a way to store that power.  Capacitors are even worse than the best batteries in terms of energy density, although the charge/discharge efficiency and cycle limits do help this equation.  And the best batteries are still not good enough for this application.

So what breakthroughs are needed, and what can we anticipate?

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I'm not one to always be looking for the newest shiny technology that's perpetually 20 years off but I'm keeping an eye on direct solar-to-hydrocarbon technology. The inputs are CO2, water, and photons and the product is long-chain hydrocarbons with all the energy density thereof but without the messy and costly step of having to go through algae or other biological intermediaries for the conversion process. Of course, the fit with existing infrastructure is great. 

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1 hour ago, valis said:

Mike, is there any way to make the hydrogen that doesn't consume more power than it provides, or at least has no more loss than using electricity to charge a battery?  Sure, hydrogen burns clean, and it has a pretty good energy density, but until we get clean electric power aren't we just moving the pollution from one place to another?

And capacitors?  Current technology gives about 50 Wh/liter stored energy density.  Compare that to 10,000 Wh/liter for diesel fuel.  Is there any realistic possibility that the capacitor energy density can be improved 200X?  Or even 20X?  At some point, the cost savings of paying for recharge electricity (vs burning diesel fuel) will tip the scale, but you need a way to store that power.  Capacitors are even worse than the best batteries in terms of energy density, although the charge/discharge efficiency and cycle limits do help this equation.  And the best batteries are still not good enough for this application.

So what breakthroughs are needed, and what can we anticipate?

Hydrogen will always require more power than it provides. Some people claim it doesn't when they use natural gas to get the hydrogen, but then you're just using very old solar energy that made the fossil fuel. If you're electrolyzing water then it's basically just a very efficient battery ... but, you can get the hydrogen with power that you would otherwise have to throw away, like nighttime baseload, so it's definitely viable. You're right, hydrogen isn't really a power source, it's a form of energy storage.

But then when you really think about it, gasoline, diesel, bunker oil or natural gas is a form of energy either, they're also energy storage, they have stored the solar energy in a fossil form through photosynthesis back when dinosaurs were around.

And yes, neither capacitors nor batteries can touch the energy density of liquid fuels. But I like capacitors because they bypass the phase change problems of batteries and unlike batteries they seem to be following their own Moore's Law of development; a 1 Farad capacitor cost about a thousand bucks when I was a kid, and it was the size of a small refrigerator. Now it's about ten cents and it's the size of an M&M candy. There is still a lot of progress needed, as well as circuit management because capacitors aren't constant voltage. But as we get better at nanoscale fabrication, we'll find geometries and materials that can polarize a lot more charge in a smaller space. I guess the needed breakthrough is some kind of nanoscale printing method with carbon.

To me, it's easier to manage charge on an engineered surface in a capacitor than in an engineered molecule. I know that we're good at making mountains of microchips with nearly perfect repeatability, and avoid the phase loss of burning stuff and chemical storage. Istream is probably right, there is good work in solar to hydrocarbon, but with things like algae, the efficiency of photosynthesis is about 12%. Then you have to dewater the biomass, concentrate it, refine it, then burn this expensive engineered molecule.

 

 

 

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41 minutes ago, mikewof said:

But then when you really think about it, gasoline, diesel, bunker oil or natural gas is a form of energy either, they're also energy storage, they have stored the solar energy in a fossil form through photosynthesis back when dinosaurs were around.

True, but I suggest that this isn't a particularly useful way to look at it.  Take it back far enough and we have to consider the stored energy density of the big bang monobloc.  I don't think I'd be very comfortable carrying one of those on my boat!  And recharging it would be a bitch.

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56 minutes ago, mikewof said:

Hydrogen will always require more power than it provides. Some people claim it doesn't when they use natural gas to get the hydrogen, but then you're just using very old solar energy that made the fossil fuel. If you're electrolyzing water then it's basically just a very efficient battery

Shouldn't you say "a very inefficient battery"?  Modern electrolysis is only about 60% efficient when comparing the energy used to convert water to hydrogen and pressurize it for storage, to the thermal energy of the hydrogen produced.  But I guess the question is "efficient compared to what?"  I don't know the refining efficiency for diesel fuel, solar panel conversion is about 20%, windpower conversion is theoretically limited to under 60%, etc.  But I'm mixing conversion efficiency with storage efficiency.  Using hydrogen as an "energy battery" doesn't seem very efficient.  I suppose if the conversion energy is cheap (your off-peak electricity), then using that to convert water to hydrogen may be better than the other alternatives.

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5 hours ago, valis said:

Shouldn't you say "a very inefficient battery"?  Modern electrolysis is only about 60% efficient when comparing the energy used to convert water to hydrogen and pressurize it for storage, to the thermal energy of the hydrogen produced.  But I guess the question is "efficient compared to what?"  I don't know the refining efficiency for diesel fuel, solar panel conversion is about 20%, windpower conversion is theoretically limited to under 60%, etc.  But I'm mixing conversion efficiency with storage efficiency.  Using hydrogen as an "energy battery" doesn't seem very efficient.  I suppose if the conversion energy is cheap (your off-peak electricity), then using that to convert water to hydrogen may be better than the other alternatives.

For grid-scale storage (and container ships are nearly grid-scale) batteries still aren't too feasible except in a distributive way, like in a hundred thousand EVs. (Those megawatt batteries do work, but with their lifetimes they are very expensive.) The current practical grid storage is pumped water, compressed air, and thermal. On a grid scale, hydrogen production from water seems to be an order of magnitude more efficient than batteries. On a small scale though, batteries still win because you don't need the storage and the fuel cell.

And yes, you nailed it, when your power is free (like nighttime excess baseload) then hydrogen is super efficient. Even with free power, storing utility scale power in batteries still isn't efficient. And cheap energy storage is the main issue as all of these coal plants go offline, because as we move to more natural gas baseload, we then risk not being able to get enough gas for power when it is needed to heat buildings. Stored power becomes more important, so that the peak loads can be managed. I would still pick pumped power or compressed air over hydrogen, but hydrogen is dead easy to set up and doesn't need geologic features like caverns and lots surface water with an elevated place to pump it.

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5 hours ago, valis said:

True, but I suggest that this isn't a particularly useful way to look at it.  Take it back far enough and we have to consider the stored energy density of the big bang monobloc.  I don't think I'd be very comfortable carrying one of those on my boat!  And recharging it would be a bitch.

All power is solar, except for ocean power, geothermal, and nuclear, and nuclear is too expensive now that we don't need enriched uranium for the Cold War.

Every form of solar power suffers from either entropy (i.e. air pollution or limited resources) or intermittency. So that's a useful way to define it. 

Ocean power could run everything, but as most sailors know, building anything to work in the ocean tends to suck up money like a crack whore sucking cocaine through a utility hose. We haven't cracked ocean power yet. When we do though, it will become our new baseload power.

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48 minutes ago, mikewof said:

Ocean power could run everything, but as most sailors know, building anything to work in the ocean tends to suck up money like a crack whore sucking cocaine through a utility hose. We haven't cracked ocean power yet. When we do though, it will become our new baseload power.

Meaning wave and current and tide energy?  I've often wondered about somehow connecting a generator to my floating dock, which the tide raises and lowers twice a day, up to 12 ft range.  Speed of the rise / fall is an issue, and I hope I wouldn't need some secondary mechanical energy storage mechanism before I could convert the energy to electricity.   OK, how much does my dock weigh?  I need to crunch some numbers.

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2 hours ago, valis said:

Meaning wave and current and tide energy?  I've often wondered about somehow connecting a generator to my floating dock, which the tide raises and lowers twice a day, up to 12 ft range.  Speed of the rise / fall is an issue, and I hope I wouldn't need some secondary mechanical energy storage mechanism before I could convert the energy to electricity.   OK, how much does my dock weigh?  I need to crunch some numbers.

There isn't much energy in that. Say your floating dock weighs a 2,000 kg, and the tide rises it 3.6 meters, twice a day. That potential energy is 2 * 2000kg * 9.8m/s^2 * 3.6 = 141 kJ. If you stored the power in a battery and used it for a hour a day, with you coupling loss, phase conversion in and out again that's only about 1kW. 

But if you coupled the wave energy (assuming you were on the shore rather than in a bay) over even 1 foot rise/fall with 3 waves/min, that's 3*60*24*2000*9.8*0.3 = 25,000 kJ. That's useable, you could potentially grid-tie that if you conditioned it, or set up a compression column to run a little homebrew wells turbine.

One thing that I'm surprised nobody ever developed is a mooring or dock stabilizer for boats that charges the house battery with the rising and falling waves ... convert some of the unwanted pitching and rolling at anchor to useable power.

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3 minutes ago, mikewof said:

There isn't much energy in that. Say your floating dock weighs a 2,000 kg, and the tide rises it 3.6 meters, twice a day. That potential energy is 2 * 2000kg * 9.8m/s^2 * 3.6 = 141 kJ. If you stored the power in a battery and used it for a hour a day, with you coupling loss, phase conversion in and out again that's only about 1kW. 

I never said it would be a good idea!  But wouldn't the energy be double that since we can extract energy from both the rise and the fall?  And even more than that since on the rise we can "push" against the substantial positive flotation.  But even it it's 2kW, that's the same daily power production as 400W of solar panel, at perhaps only 100X the price (if I could figure out how to build the thing.)  But I bet I could launch a kickstarter project and get lots of fawning press coverage if I tried.  People want to believe...

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