How would this ship fare in a Force 11 storm?

Not going under any bridges will limit access to some harbours.
I bet it would redefine sea sickness on a whole new plane too.

"You can compare a symmetrical airfoil with a 'normal' sail" To my knowledge lift of a 'normal' sail (or a plane's wing) is generated exactly because of its a-symmetrical shape. The lift is transformed into a forward directed movement thanks to the working of the keel, which takes me to another question for such a ship. What does the text means by:"lift is generated when the wind comes from both port and starboard sides." ? Wind blows in only one direction at one particular moment, the movement of the ship also creates wind, but this is not what is meant here.

I suppose it works in much the same way the blade of a Darrieus wind turbine does by using the forward force vector generated by the aerofoil shape. If that is the case, I wonder how much forward force is generated at the bow end when there is a tail wind.
60% saving seems optimistic, but I am no aerodynamicist.
It would be interesting to see if stacking containers in a teardrop shape on a conventional container ship would provide any fuel saving, and if so, would it be enough to compensate for the reduced number of containers carried per voyage. (Of course, the tail of the teardrop could take the form of a wind inflated tapering shape at the stern just big enough to maintain laminar flow.)

Really bad idea, unless you have an adjustable ballast that would allow you to lower and raise the ship when storms come but this would take a significant amount of energy to raise a ship as large as this. Still in good weather you could skirt across the ocean quickly and when a storm came you could take on ballast and make the ship significantly more stable then most ships today with a greater ballast. I hope this is their concept.

This looks like it would need a huge keel for stability, which would keep it out of most ports.

well, we're not exactly naval engineers around here, but the idea seems to hold some... wind to it. There's ample wind in the sea, and it can be put to good use, why not?
I'm not sure how the ship (and its cargo) will fare on very rough seas, though. But I guess that's something naval engineers know how to solve :)

It seems similar (using wind to help power the ship) to Jaques Cousteus ship that has turbo sails on it. It does look cool but one wanders if the wind could top over such a tall ship?

I don't see the wind propulsion working well.
I would expect better than 80% reduction in emissions of pollution over a ship burning Bunker C just by going to burning methane and using a catalytic converter.

The site of the 'designers' shows the ship being loaded by trucks. Presumably this is because some bright spark twigged that it will be impossible to load this baby with gantry cranes. Whoops.
They clearly have no understanding of how modern shipping works.
Hats off for having a go, though.