Why can't cargo ships deploy floating solar panels to power the ship motors?
i'm guessing there's more research to make it feasable since i haven't seen "carbon neutral gas alternative" at the local Chevron.
Since solar panels are very thin and aimed up, it feels like they add minimal cross-sectional area to the craft. Your assertion seems trivially incorrect to me?
The requisite area to power a ship is huge, something like 1.4km^2 (ballpark estimate for 20% cells, reasonable capacity factor guess, 60 MW consumption requirement). If a ship is about 30m wide, it's trailing about 45 km of PV. You're not even into 4 digits of cargo ships before the combined length is longer than the circumference of the planet.
Drag (fluid mechanics generally) is... ludicrously complicated. For the typical shapes of ships, I believe you are correct that the main factor is cross sectional area perpendicular to the direction of travel, but that’s not universally true. i think that for a floating raft of panels, it would be proportional to the panel area, similar to how for winged aicraft its the wing area and not the cross section perpendicular to direction of travel.
You see solar panels added to a wide range of boats because even bunker fuel isn’t free and panels are light for the power they provide over even a few days. A current 399.9 * 61.3m container ship doesn’t need panels everywhere to benefit, but the potential savings is significant if they do.
“Lowering speed reduces fuel consumption because the force of drag imparted by a fluid increases quadratically with increase in speed. Thus traveling twice as fast requires four times as much energy and therefore fuel for a given distance.”
https://en.wikipedia.org/wiki/Slow_steaming
“Container ship Emma Mærsk in Aarhus, 5 September 2006 Mærsk Line's E-class container ships such as the Emma Mærsk can save 4 metric kilotons of fuel oil on a Europe-Singapore voyage by slow steaming.[5] At typical fuel prices of US$600-700 per tonne,[4] this works out to a saving of US$2.4-2.8 million on a typical one-way voyage. Maersk's Triple E-class container ships were designed for slow steaming and have less powerful engines than their predecessors.[5]”
Put another way if there was excess torque being generated it would go somewhere such as increasing the engine RPM.
For example, one tonne of fuel is about 11 MWh. So if you run the calculations, you will see that adding solar panels to a diesel boat, even if the energy they provide is free, essentially never ROIs, and makes the boat less reliable and useful as a boat.
These kinds of engines generate tens of megawatts when they are on, and they are always on when the ship is moving.
The reality of large internal combustion engines is you still pay for every single kWh. These ships already have extremely complex electrical systems with multiple redundancies and load balancing etc.
The dealbreaker is R&D as unlike a house or sailboat you can’t just yolo where panels are placed and wires run etc, this is all bespoke engineering with few of any give design being manufactured and little available space.
If you said fuel was 5.5 MWh per tonne people would wonder what you cut it with.
The reality of outputting 80MW is that the power to your lights is a rounding error and you’d be better off buying a robot to regularly clean the hull.
That’s almost correct, good try.
> lights is a rounding error
Ships use electrical power for far more than lighting, and no electricity is not a rounding error compared to profit it’s a significant expense for cargo ships.
The solar panels would be more expensive than bunker fuel.
Sails would be cheaper.
maybe with an emergency diesel engine in the back.
https://www.newscientist.com/article/2445620-worlds-largest-...