While some short distance Ferries have have already gone battery-powered these were across short strips of water. The British channel is a slightly different magnitude of issue. Although the crossing is only 20-30 miles wide (at its shortest) this is still an order of magnitude larger than on pure battery powered craft that have been used in the past.
Encouragingly this is not been forced on P&O as as they have seen that the financial advantage is is in favour of upgrading their craft. Given that each of these craft cost more than 200 million pounds, this advantage is pretty large. I suspect that within the next decade there will be various ferries that can do this journey entirely on battery power.
While it will also have fossil fuel power any excess energy will also be used to recharge the batteries thus further increasing the efficiency of the ferry in question.
The efficiency of electrical power and and this ferrys setup will mean that they will be able to save around 40% of the emissions. Given that this will also be a saving of roughly 40% of their fuel it will also mean roughly 40% saving on this a not insignificant amount making the ferry more money for it’s owners.
While this is a first small step for for Channel crossing ferries it is an important one and as consumers we must keep up pressure on the companies to follow this up with more that is required in the next couple of decades.