I would LOVE a deep dive into the infrastructure necessary to charge this thing. They claim it will charge overnight, napkin math has that at roughly 3/4MW. Them's decidedly not rookie numbers. Extrapolating into the future, I imagine a busy port has some fairly reasonable number of tugboats (hard to find info on this) but for simplicity of the math let's say there are 12 and they have a 2/3 duty cycle, so we have 3MW of power being drawn constantly? I guess in the scheme of a port that might be a nothingburger but would love to know more.
> They claim it will charge overnight, napkin math has that at roughly 3/4MW. Them's decidedly not rookie numbers.
One could argue those are rookie numbers[1]:
Bastø Electric uses batteries with a capacity of 4.3 MWh. The fast-charging system has a capacity of 9 MW, according to the shipping company.
Not sure exactly how they do it but another ferry used on-shore batteries as a buffer[2], not unlike decoupling capacitors in electronic circuits. I agree a deep dive in the charger infrastructure would be interesting.
The ferry between Helsingør in Denmark and Helsingborg in Sweden has a 10MW charger at each side, to charge for 4-9 minutes depending on the timetable. (It runs back and forth all day and all night, carrying people, cars and trucks.)
See the chapter "Robot Arm" in this video to see it coupling.
10MW is around the power for an electric freight train, so these kind of numbers aren't uncommon for a port.
Burning 24.5 gallons of diesel makes 1 MWh of heat, so at 50% efficiency call it 50 gallons per MWh .
This makes the 6.2 MWh battery equivalent to about 300 gallons of diesel.
If you plug in this battery to charge at 1MW, it will take about 360 min to charge, so a 1 MW charging station is equivalent to a gas pump that pumps about one gallon per minute.
I do not think they are using the blue plugs shown in the picture for charging the battery. Those look like 480V 150A plugs to me, and those can only supply 0.077 MW. It is more likely those blue plugs are for "Shore Power" used while in port for stuff like like air conditioning, computers, cooking.
That's pretty cool, we'd often cross paths with tug boats tasked with moving container ships while sailing out on SF bay and their dual exhaust pipes are ridiculously huge relative to the size of the vessels. It's like a floating giant diesel engine with a helm+rudder attached.
I look forward to the era of day sails without the nauseating stink of diesel/bunker oil exhaust streams, probably not in this lifetime though.
> It's like a floating giant diesel engine with a helm+rudder attached
Funny. When I read the title, I immediately thought of a Naval Architecture professor who described tugs as "a floating engine with an insane amount of horsepower."
Tugboats are pretty incredible. Compared to container ships they look tiny, but they are actually pretty big. During Kings Day in Rotterdam I saw tugboats basically pirouetting in place while blasting water cannons. Way more nimble than even what I’ve seen from ski and wakeboard boats.
It's not a misquote at all. It's a hybrid. If batteries are nearly flat, and there is an emergency, the tug will switch over to its diesel engine and power itself over to the emergency task.
I don't think that's a fair assumption at all. There's a world of difference between being able to propel yoursellf versus relying on another vehicle when the emergency may occur in rough seas or busy channels.
Also the assisting tugboat would have to leave its station to assist to emergency boat.
But no, in general tugs don't always operate with a buddy.
