Our set up Mitsubishi Outlander PHEV towing Swift Conqueror 480 1500kg starting with a full charge leaving our house travelling between 30 and 40mph (speed restrictions) to pick up the M6 Toll road 14 miles requires approximately 9.6kW, however the faster you go the less distance per kW, so in theory to tow a 1500kg (which is about the average weight of a modern UK caravan) at 50/55mph will require approximately 100kW taking into account regenerative energy recovery, so not really brilliant.
The caravan chassis manufacture AL-KO has already developed a caravan chassis designed with electric towcars in mind with regenerative energy recovering whist being towed, 80/100kW batteries and electric motors in the wheel hub, this can be topped up by solar panel of the caravan roof or charging up off the mains on site. The biggest problem at this moment in time is the weight of the batteries and obviously the cost.
The alternative is to take advantage and carryout a motorhome conversion on the current electric panel van appearing on the market like Ford/Mercedes etc, that way all the development cost being meet by the manufacture plus access to fast charging points
Unfortunately I have suffered a brain injury and occasionally I get confused and often say the wrong thing.