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Tesla Cargo Ship

Buckminster

Active Member
Aug 29, 2018
3,562
19,048
UK
Watching the RO-RO ships travel around the world, something struck me.

I've written a couple times (here and elsewhere) about how while it's not economically practical (with current tech) to make large electric-powered cargo ships that travel nonstop (don't care to redo the calculations yet again, but feel free to do them yourselves), it is economically practical to use them with floating "gigachargers" (deep sea wind, floating solar, inside a breakwater - ideally with the breakwater being a wave-power generator). These would transfer - for ships the size of a Maersk Triple-E - about a gigawatt hour per 80% charge, about every day or so.

Something occurred to me, though - and the situation could actually be a lot more than merely "economically practical" - rather, a major economic advantage.

Speed is a key part of the economics of shipping. For one, the faster you deliver your cargo, the more trips you can take. For another, the faster you deliver cargo, the more you get paid for that delivery (the reason why people do air shipping even though it's insanely expensive compared to shipping at sea). Double the speed and you might quadruple your revenue, for a given capital investment.

So why don't ships just go faster? Energy consumption, of course (operations, not capital, costs). The faster you travel, the more energy your ship has to burn to do so. Ships today don't want to have to pay more for fuel, so their cruising speeds are limited (the Glovis fleet usually cruises at about 20mph/30kph, for example).

Now, this might seem even worse for electric shipping. After all, big batteries are expensive, and the more power you burn, the larger the battery you need to have in order to charge at a given interval. But what happens if we reduce that interval significantly?

The rate at which you can charge a battery pack is irrespective of the size of the battery pack; for a given cell and cooling design, a 1kWh pack takes the same amount of time to charge as a 1GWh pack. A ship can do the same 30 minute 0-80% that a car or truck can, so long as the charger are sized to do so (just through a *much* fatter, crane-hoisted cable!). You certainly have more overhead - sailing a ship into a breakwater, docking alongside a charger tower, and connecting a liquid-cooled cable wider than your thigh, is not a 1-minute job like parking your car at a Supercharger and plugging in. But assuming that overhead can be kept "reasonable", there's nothing to stop you from charging far more often than once per day.

(Note that electric propulsion makes things like azimuth-mount thrusters ("azipods"), which allow ships to sail sideways and tightly control their position, more practical)

Let's say that instead of sailing for 23 hours and docking / charging for 1 hour, you sail for 5 hours then dock/charge for 1 hour. Now you're charging 4 times as much energy per day, for 87% as much sailing time. Burning four times the power lets you roughly double your travel speed - ~40mph/60kph. Meaning you can depreciate your capital costs across far more trips, and get paid more per trip for the faster delivery speed.

The only downside is that you burn twice as much power per trip. From an environmental standpoint, it's really a nothing issue: it's the power of the wind and/or sun, and most of the world's oceans are "deserts" - vast expanses with relatively little life, due to the lack of the sort of nutrient upwellings that you get near the coasts:

Seawifs_global_biosphere.jpg


In the above map, dark red zones have 1000 times more photosynthesis as dark blue zones, 150 times more than cyan zones, and 50 times more than green zones. It's mineral-limited, not sun-limited; if you block some sun in one location, it just leaves the minerals for the next bit over. On the other hand, sea life tends to flourish around manmade floating structures, akin to how it does around reefs.

Historically, ships have been getting a great rate on fuel costs, as they've been burning high-sulfur bunker fuel. Those days come to an end at the end of this year - the standards on bunker fuel have been raised to the point that it's now basically diesel, and in direct competition with diesel to boot. Ships can still use low grade fuel, but only if they put in (expensive) scrubbing systems on their ships that may cost more than just switching fuels. You're looking at at least "$2/gal" equivalent (prices are usually measured in $/MT), and more if oil prices rise from their (currently low) pricing regime, or further emissions restrictions (or carbon taxes) increase costs further. Let's say a long-term average of $2,50/gal - and that may well prove incredibly optimistic in the long run.

Ship engines are efficient - about 50%. Now, EV motors would also be unusually efficient in such situations, as they'd be large motors tuned for cruising speeds, and the charging process would also benefit from operation at scale. Let's say 87% round-trip efficiency. The fuel-powered ship gets propulsive energy for 27MJ/$. So if we're doubling the propulsive energy requirements, in order to match the price, electricity (at industrial rates, not home rates) needs to be generated at 54MJ/$ - aka, $0,067/kWh. Remember that it doesn't actually need to match bunker fuel costs, as you're shipping at nearly double the rate, drastically slashing your depreciation per trip while drastically increasing your income per trip.

That said, it would be awesome if electricity costs could beat fuel costs even when moving at double the speed. Is $0,067/kWh achievable? Well... "probably"?
  • Floating solar plants have so far mainly been built in freshwater, but if you have an effective breakwater, then it just comes down to an issue of material compatibility. Prices are similar to that of land-based PV - for example, Three Gorges Group is making a 150MW floating solar plant for a construction cost of $151M, or $1/W. That's just a few cents per kWh generated. The fixtures are more expensive, but installation is simpler and cheaper, on cheap/free "land". Since floating solar is a newer technology, it also has more room for price improvement.
  • Deep sea wind is not yet there in pricing; it's currently significantly more expensive than land-based and shallow-water wind. That said, it's also highly immature, and has a lot of room for improvement (and all oceanic wind has the advantage of being basically unlimited in tower height, with hardware shipped cheaply to its destination). Additionally, one of the major costs of deep-sea wind is transmission back to the shore, which is not applicable here.
  • Wave power is currently expensive, but regardless, not much is needed - only enough to make a breakwater.
Floating solar, at present, looks like the most realistic option for the bulk generation, with deep sea wind only as a supplement (turbine towers could double as platforms for storing charging hardware and/or docking ports)

Can chargers (and battery banks) be built at scale, using adjacent-generated solar at current solar pricing, and sell power for $0,067/kWh? That's harder to say - but this is exactly Tesla's plan for megachargers for Semi - and their announced pricing is $0,07/kWh (combining the low cost of solar generation with the battery banks it needs to be a reliable power source (direct DC/DC conversion, no grid costs) - batteries which simultaneously enable high charging speeds using said same DC/DC converters). A gigacharger would gain even larger economies of scale.

So... "probably". But the key aspect is: you can earn drastically more revenue from your ship if you run it on electricity, by sailing faster - since your fuel is cheap, clean, and it's much cheaper to add more electric powertrain power than diesel power.

Great idea to electrify bulk shipping!

A couple of thoughts:
  • Business model: I believe it would make sense to approach this issue from the high end as well, just like Tesla approached automotive electrification: instead of bulk cargo, go for really high speed sea delivery, with an electric fleet. Delivery times to Europe and China within 1 week will already favorably compete with air freight - which is a big and lucrative market. A 4x speedup to ~80 mph (radar assisted, of course) would cut delivery times to Europe from 20 days to 5 days and to China from 30 days to ~7 days. 100 mph+ would push things from a safety POV though, but would be even more lucrative.
  • Cell longevity is going to be an issue, as the major depreciation factor. The current global commercial shipping fleet's average age is over 20 years. Steel ship hulls can go on forever, and are expected to. How long are the best cell going to last, and what the degradation curve and how predictable are the failure modes?
  • Battery module safety: that's a lot of energy stored, many tons of TNT-equivalent, with the nearest fire trucks thousands of kms away. Robust, yet environmentally friendly modes of fire suppression of a battery fire have to be found - probably by compartmentalizing/sealing battery modules where a fire could not escape even if a runaway thermal reaction triggers inside.
  • Electric motors have other advantages over diesel motors: the huge engines of the really huge cargo ships can take more than an hour to warm up for departure. With an electric ship the ship is immediately ready for departure the moment the containers are loaded. More 'just in time' logistics are possible with an electric fleet.
  • "On the go" recharging: it takes capital investment but it's possible to do recharging "on the go": "recharging ships" which carry nothing but huge batteries, shuttling between cargo ships. The recharging ships would then periodically dock with the off-shore wind farms to recharge themselves. If there's enough of them then the offshore wind farms don't need any battery capacity at all: there would always be a "recharging ship" docked, using up available generated electricity.
  • What are the risks of weather patterns with too little or too much wind, and the resulting disruption to available energy? Delivery times must be guaranteed even in the face of hurricanes or doldrums. There must be a fail-safe plan to keep the spice going, probably by having the 'recharging ships' go back to the cost for electricity, or enough solar energy to keep things going in the worst case.
 

AudubonB

One can NOT induce accuracy with precision!
Mar 24, 2013
8,358
30,335
I’m not awake yet so there’s no excuse for my writing this but...
Re: Karen’s e-ships. Wouldn’t this entail re-designing all RO-ROs such that their hull speed (that’s a strict nautical engineering term) is greater than the Big Brick that they currently are? You’d end up looking more like an aircraft carrier than a car carrier.

Going back to sleep now.
 

KarenRei

ᴉǝɹuǝɹɐʞ
Jul 18, 2017
9,619
104,589
Iceland
Yes, optimal hull shapes are different for higher-speed ships than lower-speed ships.

Great idea to electrify bulk shipping!

A couple of thoughts:
  • Business model: I believe it would make sense to approach this issue from the high end as well, just like Tesla approached automotive electrification: instead of bulk cargo, go for really high speed sea delivery, with an electric fleet. Delivery times to Europe and China within 1 week will already favorably compete with air freight - which is a big and lucrative market. A 4x speedup to ~80 mph (radar assisted, of course) would cut delivery times to Europe from 20 days to 5 days and to China from 30 days to ~7 days. 100 mph+ speeds would push things from a safety POV though, but would be even more lucrative - and might allow approaches like a catamaran design, which would lower sea resistance and reduce energy costs.
  • Cell longevity is going to be an issue, as the major depreciation factor. The current global commercial shipping fleet's average age is over 20 years. Steel ship hulls can go on forever, and are expected to. How long are the best, most durable cells going to last, and what is degradation curve and how predictable are the failure modes, and is there a continuous maintenance mode that effectively refreshes all cells over the long run?
  • Battery module safety: that's a lot of energy stored, many tons of TNT-equivalent, with the nearest fire trucks thousands of kms away. Robust, yet environmentally friendly modes of fire suppression of a battery fire have to be found - probably by compartmentalizing/sealing battery modules where a fire could not escape even if a runaway thermal reaction triggers inside. There's a billion dollar ship to protect ...
  • Electric motors have other advantages over diesel motors: the huge engines of the really huge cargo ships can take more than an hour to warm up for departure. With an electric ship the ship is immediately ready for departure the moment the containers are loaded. More 'just in time' logistics are possible with an electric fleet.
  • "On the go" recharging: it takes capital investment but it's possible to do recharging "on the go": "recharging ships" which carry nothing but huge batteries, shuttling between cargo ships. The recharging ships would then periodically dock with the off-shore wind farms to recharge themselves. If there's enough of them then the offshore wind farms don't need any battery capacity at all: there would always be a "recharging ship" docked, using up available generated electricity.
  • What are the risks of weather patterns with too little or too much wind, and the resulting disruption to available deep sea wind energy? Delivery times must be guaranteed even in the face of hurricanes or doldrums. There must be a fail-safe plan to keep the spice going, probably by having the 'recharging ships' go back to the coast for electricity, or enough solar energy to keep things going in the worst case.

Great commentary.

  • Since you'd only ever charge up to 80% or so of nominal capacity (nobody is going to sit around deep sea waiting to charge to 100%), cell lifespan should be excellent. That said, you'd surely expect 1 or 2 battery swapouts over the lifespan of a ship. That said, maintenance on diesel engines over the lifespan of a ship isn't exactly cheap either ;) Tesla powerpack expected lifespans are 15 years.
  • Thankfully, the way you put out a li-ion battery fire is... water (and lots of it). Hmm, where could one find a ready supply of water.... ;)Basically, you'd just design every powerpack/megapack/whateverpack onboard to be able to be flooded.
  • You could even do more than that re: shuttling power. A ship with a >1GWh battery aboard could literally transport backup power from one port to another, for the costs of ship rents (I worked it out a while ago... it works out to somewhere between a fraction of a cent and several cents per kWh, depending on what ship rents are like at that given point in time - they vary a lot). Also, having multiple ships in a port with GWh battery packs and V2G connections would be a massive grid buffer. We're talking "Buffering entire coastal states / countries".
  • Wind/waves and solar tend to run opposite each other at sea, which is why they're a good complement to each other. Regardless, just like shipping is already routed based on weather, routes can also take into account price of power at a given charger, which would be proportional to how much it's generating / has stored and how much it's forecast to have when a ship arrives. More price-sensitive ships would take the cheapest route, while more time-sensitive ships would take the fastest route.
Whenever freight shipping goes electric, it's going to take a LOT of battery cell output to supply it. ;) It's a massive, massive market.
 

mongo

Well-Known Member
May 3, 2017
13,449
41,952
Michigan
I’m not awake yet so there’s no excuse for my writing this but...
Re: Karen’s e-ships. Wouldn’t this entail re-designing all RO-ROs such that their hull speed (that’s a strict nautical engineering term) is greater than the Big Brick that they currently are? You’d end up looking more like an aircraft carrier than a car carrier.

Going back to sleep now.
The non super-carriers look like they do in large part to having a waterline that fits through the Panama canal and a top deck that fits a fleet of aircraft with minimal drenching of top and hanger deck during storms. The super-carrier are too wide at the deck level and possibly too tall to pass, untill the Panama Canal expansion happens.

A longer ro-ro with the same hull same as current ones would have similar cross section in the water and less drag per car. extending the hull while not increasing tonnage would reduce drag, but have other impacts.
 
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Fact Checking

Well-Known Member
Aug 3, 2018
7,517
120,763
Vienna
Great idea to electrify bulk shipping!

A couple of thoughts:
  • Business model: I believe it would make sense to approach this issue from the high end as well, just like Tesla approached automotive electrification: instead of bulk cargo, go for really high speed sea delivery, with an electric fleet. Delivery times to Europe and China within 1 week will already favorably compete with air freight - which is a big and lucrative market. A 4x speedup to ~80 mph (radar assisted, of course) would cut delivery times to Europe from 20 days to 5 days and to China from 30 days to ~7 days. 100 mph+ speeds would push things from a safety POV though, but would be even more lucrative - and might allow approaches like a catamaran design, which would lower sea resistance and reduce energy costs.
  • Cell longevity is going to be an issue, as the major depreciation factor. The current global commercial shipping fleet's average age is over 20 years. Steel ship hulls can go on forever, and are expected to. How long are the best, most durable cells going to last, and what is degradation curve and how predictable are the failure modes, and is there a continuous maintenance mode that effectively refreshes all cells over the long run?
  • Battery module safety: that's a lot of energy stored, many tons of TNT-equivalent, with the nearest fire trucks thousands of kms away. Robust, yet environmentally friendly modes of fire suppression of a battery fire have to be found - probably by compartmentalizing/sealing battery modules where a fire could not escape even if a runaway thermal reaction triggers inside. There's a billion dollar ship to protect ...
  • Electric motors have other advantages over diesel motors: the huge engines of the really huge cargo ships can take more than an hour to warm up for departure. With an electric ship the ship is immediately ready for departure the moment the containers are loaded. More 'just in time' logistics are possible with an electric fleet.
  • "On the go" recharging: it takes capital investment but it's possible to do recharging "on the go": "recharging ships" which carry nothing but huge batteries, shuttling between cargo ships. The recharging ships would then periodically dock with the off-shore wind farms to recharge themselves. If there's enough of them then the offshore wind farms don't need any battery capacity at all: there would always be a "recharging ship" docked, using up available generated electricity.
  • What are the risks of weather patterns with too little or too much wind, and the resulting disruption to available deep sea wind energy? Delivery times must be guaranteed even in the face of hurricanes or doldrums. There must be a fail-safe plan to keep the spice going, probably by having the 'recharging ships' go back to the coast for electricity, or enough solar energy to keep things going in the worst case.
 

Etna

Member
Jan 31, 2017
386
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Québec City
I ran some numbers on a ULCC class ship awhile ago (and created the 3D model below just for fun). A trip of 6800 nm would require about 30 GWh.

If you want to check my math, that's 17.75 days at 16 knot with the engine producing 35MW (440000 DWT, sea margin 15%, engine margin 10% no ice class notation, no currents, no reserve, source https://marine.mandieselturbo.com/d...rs/propulsion-trends-in-tankers.pdf?sfvrsn=20).

30 GWh at 100$/kWh that's a battery pack cost of... 3 billion dollars. A little bit on the expensive side.

For the foreseeable future, the financing cost kills the business case of long distance electric ships. It does work on short distances though, like ferries.

Powership.jpg
 

KarenRei

ᴉǝɹuǝɹɐʞ
Jul 18, 2017
9,619
104,589
Iceland
I ran some numbers on a ULCC class ship awhile ago (and created the 3D model below just for fun). A trip of 6800 nm would require about 30 GWh.

If you want to check my math, that's 17.75 days at 16 knot with the engine producing 35MW (440000 DWT, sea margin 15%, engine margin 10% no ice class notation, no currents, no reserve, source https://marine.mandieselturbo.com/d...rs/propulsion-trends-in-tankers.pdf?sfvrsn=20).

30 GWh at 100$/kWh that's a battery pack cost of... 3 billion dollars. A little bit on the expensive side.

For the foreseeable future, the financing cost kills the business case of long distance electric ships. It does work on short distances though, like ferries.

View attachment 375802

Love the picture, but I think you missed the discussion. I pointed out right at the top that making whole transoceanic trips on a single charge is impractical (your numbers roughly match with mine - and the price isn't the only problem, it also totals your cargo capacity!). That's not what's being discussed, however; what's being discussed is fast charging en route at floating "Gigachargers". Totally different paradigm.

Large ships for making nonstop electric transoceanic cargo trips will surely be possible and economically justifiable some day, but that day is not around the corner.
 
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mongo

Well-Known Member
May 3, 2017
13,449
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I ran some numbers on a ULCC class ship awhile ago (and created the 3D model below just for fun). A trip of 6800 nm would require about 30 GWh.

If you want to check my math, that's 17.75 days at 16 knot with the engine producing 35MW (440000 DWT, sea margin 15%, engine margin 10% no ice class notation, no currents, no reserve, source https://marine.mandieselturbo.com/d...rs/propulsion-trends-in-tankers.pdf?sfvrsn=20).

30 GWh at 100$/kWh that's a battery pack cost of... 3 billion dollars. A little bit on the expensive side.

For the foreseeable future, the financing cost kills the business case of long distance electric ships. It does work on short distances though, like ferries.

View attachment 375802

35MW × 24 hours × 17.75 is 15GWh, is the 30GWh number round trip?

Alternative idea:
Keeping the 30GWh number, if one used zinc air batteries instead (470 Wh/kg) and mechanically recharged them at port, with the Zinc reactivated at a renewable power facility, it would cost somewhere around $220 million for the zinc and weigh 70,212 US tons.
At 100W/kg it could pump out > 6GW.

At 20 GWh, $150 million (raw material) and 47,000 US tons, 4GW output.
Edit: units error
 
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Etna

Member
Jan 31, 2017
386
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Québec City
Love the picture, but I think you missed the discussion. I pointed out right at the top that making whole transoceanic trips on a single charge is impractical (your numbers roughly match with mine - and the price isn't the only problem, it also totals your cargo capacity!). ...

Indeed I missed your first paragraph. Total cargo capacity would not be reached though, assuming the Tesla battery packs at 0.129 kWh/kg we would get just a bit more than half the ship capacity taken out.

35MW × 24 hours × 17.75 is 15GWh, is the 30GWh number round trip?

Yes round trip, I ran those numbers in the context of delivering stored power - forgot to specify that.
 
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OPRCE

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Jun 16, 2018
861
998
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Battery only is too heavy/expensive, would recharge painfully slowly or with massive power peaks.
Hydrogen hybrid power will make more sense for large ships, once the H2 infrastructure is developed, e.g. production/storage at offshore wind-farms. Europeans and Japanese are pushing in this direction.
Example concept: Zero-Emission Container Feeder Vessel

See here for more ZE ships:
Top 5 Zero Emission Ship Concepts Of The Shipping World
 

Electroman

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Aug 18, 2012
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Deep sea wind is not yet there in pricing; it's currently significantly more expensive than land-based and shallow-water win

How about a floating platform that hosts a few giant windmills and solar panels? is that even feasible? Are hurricanes an issue then? We have deep sea drilling infrastructure that withstands hurricanes.
 

mongo

Well-Known Member
May 3, 2017
13,449
41,952
Michigan
Battery only is too heavy/expensive, would recharge painfully slowly or with massive power peaks.
Hydrogen hybrid power will make more sense for large ships, once the H2 infrastructure is developed, e.g. production/storage at offshore wind-farms. Europeans and Japanese are pushing in this direction.
Example concept: Zero-Emission Container Feeder Vessel
While the inital topic which spawned this thread was mid sea recharging, reducing the battery capacity required, I don't see that a zinc air or similar tech would be prohibitive. Either the active material or the modules could be swapped out with a dedicated unit.

At 20GWh, 47k tons on a 440 k ton ship (11%) is not excessive, it would displace 2k tons of bunker C needed (50% engine efficiency, 40MJ/kg(11.111 kWh/kg) ) and could take the place of fixed ballast.

As for fueled ships, using the Sabatier reaction, a ship could run on renewable methane instead of hydrogen. H2 wins in energy per kg, but that is not a limiting factor. Liquified Methane is 40% more energy dense than bunker-C in terms of kJ/kg, but needs 80% more space. It also provides 2 times the energy per liter as liquified Hydrogen. Plus you avoid the flammability risks of H2 along with hydrogen embrittlement.
700 bar H2 is half the energy per liter of 250 bar CH4. Pressurized Liquid CH4 requires a temp below 190K, liquid hydrogen requires 20K. Ships already transport LNG, so it's already feasible.

Of course there is also the efficiency difference between a fuel cell and a gas turbine engine.

Running a closed combustion system, the engine can recompress the CO2 produced to feed the green plant to convert back to CH4.
 
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ReflexFunds

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Dec 7, 2018
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Watching the RO-RO ships travel around the world, something struck me.

I've written a couple times (here and elsewhere) about how while it's not economically practical (with current tech) to make large electric-powered cargo ships that travel nonstop (don't care to redo the calculations yet again, but feel free to do them yourselves), it is economically practical to use them with floating "gigachargers" (deep sea wind, floating solar, inside a breakwater - ideally with the breakwater being a wave-power generator). These would transfer - for ships the size of a Maersk Triple-E - about a gigawatt hour per 80% charge, about every day or so.

Something occurred to me, though - and the situation could actually be a lot more than merely "economically practical" - rather, a major economic advantage.

Speed is a key part of the economics of shipping. For one, the faster you deliver your cargo, the more trips you can take. For another, the faster you deliver cargo, the more you get paid for that delivery (the reason why people do air shipping even though it's insanely expensive compared to shipping at sea). Double the speed and you might quadruple your revenue, for a given capital investment.

So why don't ships just go faster? Energy consumption, of course (operations, not capital, costs). The faster you travel, the more energy your ship has to burn to do so. Ships today don't want to have to pay more for fuel, so their cruising speeds are limited (the Glovis fleet usually cruises at about 20mph/30kph, for example).

Now, this might seem even worse for electric shipping. After all, big batteries are expensive, and the more power you burn, the larger the battery you need to have in order to charge at a given interval. But what happens if we reduce that interval significantly?

The rate at which you can charge a battery pack is irrespective of the size of the battery pack; for a given cell and cooling design, a 1kWh pack takes the same amount of time to charge as a 1GWh pack. A ship can do the same 30 minute 0-80% that a car or truck can, so long as the charger are sized to do so (just through a *much* fatter, crane-hoisted cable!). You certainly have more overhead - sailing a ship into a breakwater, docking alongside a charger tower, and connecting a liquid-cooled cable wider than your thigh, is not a 1-minute job like parking your car at a Supercharger and plugging in. But assuming that overhead can be kept "reasonable", there's nothing to stop you from charging far more often than once per day.

(Note that electric propulsion makes things like azimuth-mount thrusters ("azipods"), which allow ships to sail sideways and tightly control their position, more practical)

Let's say that instead of sailing for 23 hours and docking / charging for 1 hour, you sail for 5 hours then dock/charge for 1 hour. Now you're charging 4 times as much energy per day, for 87% as much sailing time. Burning four times the power lets you roughly double your travel speed - ~40mph/60kph. Meaning you can depreciate your capital costs across far more trips, and get paid more per trip for the faster delivery speed.

The only downside is that you burn twice as much power per trip. From an environmental standpoint, it's really a nothing issue: it's the power of the wind and/or sun, and most of the world's oceans are "deserts" - vast expanses with relatively little life, due to the lack of the sort of nutrient upwellings that you get near the coasts:

Seawifs_global_biosphere.jpg


In the above map, dark red zones have 1000 times more photosynthesis as dark blue zones, 150 times more than cyan zones, and 50 times more than green zones. It's mineral-limited, not sun-limited; if you block some sun in one location, it just leaves the minerals for the next bit over. On the other hand, sea life tends to flourish around manmade floating structures, akin to how it does around reefs.

Historically, ships have been getting a great rate on fuel costs, as they've been burning high-sulfur bunker fuel. Those days come to an end at the end of this year - the standards on bunker fuel have been raised to the point that it's now basically diesel, and in direct competition with diesel to boot. Ships can still use low grade fuel, but only if they put in (expensive) scrubbing systems on their ships that may cost more than just switching fuels. You're looking at at least "$2/gal" equivalent (prices are usually measured in $/MT), and more if oil prices rise from their (currently low) pricing regime, or further emissions restrictions (or carbon taxes) increase costs further. Let's say a long-term average of $2,50/gal - and that may well prove incredibly optimistic in the long run.

Ship engines are efficient - about 50%. Now, EV motors would also be unusually efficient in such situations, as they'd be large motors tuned for cruising speeds, and the charging process would also benefit from operation at scale. Let's say 87% round-trip efficiency. The fuel-powered ship gets propulsive energy for 27MJ/$. So if we're doubling the propulsive energy requirements, in order to match the price, electricity (at industrial rates, not home rates) needs to be generated at 54MJ/$ - aka, $0,067/kWh. Remember that it doesn't actually need to match bunker fuel costs, as you're shipping at nearly double the rate, drastically slashing your depreciation per trip while drastically increasing your income per trip.

That said, it would be awesome if electricity costs could beat fuel costs even when moving at double the speed. Is $0,067/kWh achievable? Well... "probably"?
  • Floating solar plants have so far mainly been built in freshwater, but if you have an effective breakwater, then it just comes down to an issue of material compatibility. Prices are similar to that of land-based PV - for example, Three Gorges Group is making a 150MW floating solar plant for a construction cost of $151M, or $1/W. That's just a few cents per kWh generated. The fixtures are more expensive, but installation is simpler and cheaper, on cheap/free "land". Since floating solar is a newer technology, it also has more room for price improvement.
  • Deep sea wind is not yet there in pricing; it's currently significantly more expensive than land-based and shallow-water wind. That said, it's also highly immature, and has a lot of room for improvement (and all oceanic wind has the advantage of being basically unlimited in tower height, with hardware shipped cheaply to its destination). Additionally, one of the major costs of deep-sea wind is transmission back to the shore, which is not applicable here.
  • Wave power is currently expensive, but regardless, not much is needed - only enough to make a breakwater.
Floating solar, at present, looks like the most realistic option for the bulk generation, with deep sea wind only as a supplement (turbine towers could double as platforms for storing charging hardware and/or docking ports)

Can chargers (and battery banks) be built at scale, using adjacent-generated solar at current solar pricing, and sell power for $0,067/kWh? That's harder to say - but this is exactly Tesla's plan for megachargers for Semi - and their announced pricing is $0,07/kWh (combining the low cost of solar generation with the battery banks it needs to be a reliable power source (direct DC/DC conversion, no grid costs) - batteries which simultaneously enable high charging speeds using said same DC/DC converters). A gigacharger would gain even larger economies of scale.

So... "probably". But the key aspect is: you can earn drastically more revenue from your ship if you run it on electricity, by sailing faster - since your fuel is cheap, clean, and it's much cheaper to add more electric powertrain power than diesel power.


I love this post, I considered the possibility of sea charging stations a while ago but never got around to running the numbers. The potential increased speed really could change the game in terms of annual profitability.

I’m starting to think shipping could be a very large market for Tesla in the short to medium term. Calculations below, but roughly I estimate a fully electric fleet could use c.10,000GWh of batteries vs 1 billion EVs at 60kWh using c.60,000GWh. Tesla could potentially enter this market with a modular battery product similar to Megapack requiring limited additional R&D, however they could also decide to develop the full electric ship powertrain in-house. Building a full Tesla ship alone seems a lot less likely, but I wouldn’t completely rule it out.

Some more thoughts and calculations below, with a lot of help from @KarenRei's previous work. I’m no expert in shipping or ship engines/motors, so let me know if anything looks off. @Fact Checking

Economics of Electric ships vs the diesel Maersk Triple E – the world’s largest container ship and best in class for energy efficiency and cost.

upload_2019-2-10_17-11-59.png


Electric ship with no chargers - Based on this model, an electric ship the size of Maersk Triple-E would need a c.20.5gWh battery to complete a c.15,000 km journey. This is clearly impossible.

Electric ship with charging stations - With sea charging stations, the ships range could be reduced to c.800km with a 1.0gWh battery. This ship would be profitable, but more expensive (even with $100/kWh total battery & powertrain cost) and less profitable than the Maersk Triple-E. Even fuel cost would be more expensive than the Maersk Triple-E at $0.1/kWh. I think this ship will become economical vs the Triple-E eventually, but it requires significant further progress on the experience curves for batteries, electric powertrains and solar.


Electric ship with charging stations at 2x speed – Diesel engines lose significant efficiency when ships are operated at faster speeds. Electric motor efficiency is much more flexible to power output. Both types of ship will see significanttly increased drag at faster speeds. I’m roughly assuming an electric ship would consume c.63% more energy per ton per km at 2x the speed, but I need to do work on this though to get an accurate estimate. Using these assumption, the electric ship now gets 500km range on a 1gWh battery, requiring charging stops every 6.4 hours. Factoring in 1.5 hour stopping time, journey time reduces by 38%. Faster journeys should command a significantly higher freight rate, and also should start to compete with air freight. Even excluding this impact, the potential to complete more journeys per ship per year leads to ship level operating profit per year 71% higher than the Maersk Triple-E on my numbers. This would achieve a 2.9-year payback on initial capex vs my 3.7-year estimate for Maersk Triple-E.

These numbers are all in comparison to a best in class efficiency Maersk Triple-E. Smaller ships are significantly less profitable due to lower fuel efficiency for smaller engines and less economies of scale. The economics of electric ships are potentially more favorable for smaller ships of a more regular size, maybe half the size of Triple-E.

A large question mark still here is what are capex requirements for building the sea charging stations. Note Hawaii solar+storage projects have hit energy prices of $0.08/kWh. Sea solar is more efficient due to cooling, real estate cost is also lower, but installation and maintenance should be significantly higher. I may take a look later at how many charging stations will be required, what size they will have to be, and how practical it is to build batteries and charging infrastructure on the ocean.

Key assumptions:

Electric powertrain: 90% efficiency pack to wheels
Maersk engine: 50% efficiency fuel to motion.
Stop time for recharging = 1.5 hours
Charging/conversion losses: 10%
Energy consumption/ton/km 63% higher at 2x speed.
Battery & Electric Powertrain Price = $100/kWh.
Maersk Triple E Powertrain cost = $55m.
Solar/wind + storage + installation total cost = $0.1/kWh. (r)
Freight fuel cost - $600/ton (currently c.$400/ton, but much more stringent emissions regulations coming soon)
Freight price = $0.041/TEU/km. (I think roughly in-line with Shanghai to Europe)
Opex = $1.5/TEU. This is mostly maintenance & ship staff costs.
Port/terminal/canal fees = 35% of revenue.
Depreciation of ship cost over 15 years.


Modular batteries?

If electric ship batteries are stored in a Tesla Megapack type container, then the ship’s range could be modular. Additional capacity could be added or removed quickly in port depending on destination distance and density of sea chargers on-route. Also, once an individual Megapack capacity degrades below 80% or so, it can very easily be recommissioned for on-land stationary storage use.

Megapacks are reportedly 2.673Mwh, so c.375 would be needed for a 1Gwh battery. These are similar in size and shape to a standard TEU shipping container. So relatively small relative to 18,270 TEU capacity on a Maersk Triple-E ship. This likely takes up c.2x the space of the bunker fuel required for a diesel ship, but after adjusting for EV vs diesel powertrain, it may not reduce the freight capacity at all.


Battery swap cheaper than supercharging?

One other thing I was thinking, though it may be stretching practicality, is a battery swap option. It looks like the fastest port in the world can make 163 container moves per hour. This could correspond to offloading and onloading c.80 Megapacks. Currently 1Gwh fits in c.375 Megapacks, which are around the size of one TEU. If Tesla makes a Megapack 4x larger, or roughly the size of 4 TEU, then specialized and automated crane technology on these sea charging stations could potentially swap out the ships entire battery capacity in 1-1.5 hours to fresh batteries. This would save the need for building expensive supercharging infrastructure, and would also lead to 100% rather than 70-80% capacity after a one hour stop. It would require some very sophisticated automated battery swap and connector technology.


A look at potential market size:

It appears total global ship fleet is c.52k vessels and 1.9 million kdwt. The Global Fleet Revealed

My example above used a large ship with 182 kdwt capacity which required c.1Gwh batteries. If the total global fleet is converted to electric, this could then require 1.9mn/182 = 10,400 ships or c.10,000 Gwh. This compares to building a global EV fleet of 1 billion cars (with average 60kwh per car) which would need 60,000 gWh. Average ship age is 8-10 years, so this could be c. 1,000-1500 gWh per year demand. However, if the economics of electric ships prove far superior, the existing fleet will rapidly depreciate and annual demand for electric ships is likely to be much higher during the transition.
 
Last edited:

Beltsbear

Active Member
Jan 1, 2016
1,071
6,362
Dc
If the battery swap idea is feasible, it would be the best one. Wind farms could be located in some locations charging empty packs, and full packs would be swapped for empty at sea. The problem is bad weather. Of course the paradigm shift could be to do ALL OF THIS UNDERWATER. Sounds radical but undersea travel can actually be faster then surface if the vessel is designed right.
 

brucet999

Active Member
Mar 12, 2015
2,696
1,569
Huntington Beach, CA
I read that article and my first thought is where all of that hydrogen would come from? I Gates going to build a huge PV or wind turbine facility to electrolyze water into H2?
Is he going to use H2 from methane steam reforming, which consumes huge amounts of power to generate the heat needed and results in production of one molecule of CO for every three H2 molecules. Getting rid of the CO by further steam reforming results in one more H2 molecule and one molecule of CO2 - exactly what would have resulted from burning the methane in the first place.
What am I missing here?
 

Electroman

Supporting Member
Supporting Member
Aug 18, 2012
6,392
7,498
TX
What am I missing here?

What you are missing is, for a vehicle like an Yacht, battery powered electric drive train is not an option. Hydrogen is next best choice. Better than running diesel engines and polluting the waters.
 

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