This is an improvement....
However why do they need 10 tonne motors for 400kW.
Possibly they should have stated the torque of the motors, as it is actually more relevant.
The 1500kW diesel motor is most likely turning at a higher rate than the stated electric motors, which are likely mated to directly to the propeller without a gearbox. The propeller may only be turning at 100-400 rpm, while a deisel engine may be rotating at 1500 RPM or greater.
As Power = Torque*Angular velocity (radians per second)
It is common for electric motors replacing internal combustion engines to be lower in power rating, as they develop a lot more torque at lower revs. Also add a more streamlined Hull, and the power reduction is not surprising....
I had a look on the map, and the distance of this ferry service (it is a regular ferry service) is only 5km. They could fairly easily avoid having to carry a large battery bank on board by using a reel in- reel out power cable carrying mains power from the shore to the boat... (If there is a mid section where the cable can be anchored to the seabed, they would only need stowage space for 3km of cable at the most.... This system is used in shuttle cars in underground mining operations... maybe this is thinking too far outside the box... Also, it is possible that the installation of the cable would exceed the cost of a batterypack with no guarantee that its life would be any greater....
One positive thing about having a trailing cable is that once it leaves the vessel, it will descend to the bottom fairly quickly as it will have a reasonably low tension on it as it is not a pull-cable.
Of course there may need to be a battery on board as well in case the power supply from shore fails.... (or the cable is cot for some reason...)
Sorry for thinking out loud.

A light and efficient hull makes sense but I would really prefer keeping several days of high energy operation worth of fuel aboard to deal with an emergency.
Granted it is unlikely that both electric grids will go down at the same time but how long will the ferry be able to keep functioning if they do? Can it stay in service if just one side looses power? How long can it stay under power if a storm make docking impossible?

@MD: I've been on one of its neighboring ferries. These ferries cross a fjord, many of which are more than 1 km deep. Anchoring a cable to the sea bed isn't an option. A cable is not an option entirely, because very large ships should be able to enter the fjord, and there are a handful of ferries in each of the larger fjords.

Slowburn, if it cant dock why would it be in service? The two areas are all of like 6km away I highly doubt a freak storm would catch them off guard. What I am curious about is how much it would cost to simply build a bridge...

re; Nick Thompson
Storms are not fully predictable. The Captain would believe that he would be able to make the trip safely but the storm gets worse faster than he anticipated. It has happened before and the captain was praised for his seamanship for taking the ferry out to sea and keeping her afloat for days. A tornado could destroy the docking facility as well.

Tornadoes that cause any kind of damage are extremely rare in Norway, and storms in those fjords are seldom very powerful because the fjords are narrow and deep most of their length. As to why they dont build a bridge, well, the problem is that the fjords mostly are very deep so you would have to have a free span of more than 5 km, and that will cost a lot, if it is technically possible. Norway only has a population of 5 million, so there's a limit as to how big projects wil be started. Also, Norway has very much hydroelectric power, more than 95%, and it would be sensible to use this power for transportation because it is completely emmission free. There are plans for a ferry-free road all along the west coast of Norway, and although this is something that probably won't be started this decade they say that the technology for this is available today. Because the fjords have been carved out by glaciers moving westwards, they have carried rocks with them and dropped them as they melted. That's why the fjords are very deep where they start and rather shallow at the point where they reach the open sea. Sognefjorden, the worlds second longest fjord at 220 km, is 1300m deep where it starts, and less than 200m at its treshold.

Using batteries to charge batteries seems like just multiplying inefficiencies. Factor in the original energy conversion of the utility plant, transmission line losses, batteries charge/discharge losses, and I suspect the actual carbon footprint is much larger now. Why not just put efficient diesel motors in the new aluminum cat? The new design alone would have cut the footprint, if that is the real driving factor here, in half.

How do they operate hydraulics and other peripheral systems? I've an EV aficionado but boats needs a lot of hydraulic pressure, usually hard to meet with electric pumps.

I call bullsh*t on the 10 minute recharge, suspect very strongly that it's actually battery CHANGE, not a battery recharge. Having worked around electric forklift trucks I can tell you unless there's been a giant leap in battery technology the batteries are probably going to be recharging at the dock and swapped out for each run.

re; PeetEngineer
Lots of tiny batteries.