Shorter routes makes relevant the higher power demand that can be met by DC-charging

Three main factors to consider when plugging in at sea.

With the increase in Electrical Vehicles on the roads, offering customers the possibility of EV-charging at sea has become an increasingly interesting business proposition for ferry-operators. The investment costs for EV-charging system(s) are relatively low, but as EV-charging applications are developed and designed to be used on land, there is a significant risk that the investment will be wasted because the application is unsuited for on board charging. To minimize that risk, Marine Charging Point has identified three major factors to consider before investing in an on board EV-charging system: 

Energy supply and power demands 
To determine the technical specifications of an on-board EV-charging system, a first and very important step is to align the power demands for EV-charging with the energy supply of your vessel.  
The power demands for EV-charging will differ rather dramatically, depending on the route characteristics of your vessel, as well as the existing EV-charging infrastructure around ports of departure and arrival. If your vessel is operating on a longer route, for instance, a number of smaller AC-charging points (e.g. 22kW) could be sufficient to cover basic power demands since the EV’s would be able to slow-charge over a longer period of time. By contrast, if your vessel is operating on shorter routes (less than an hour), power demands are likely to be better addressed with bigger DC-charging points (e.g. above 70kW) since the time for charging is relatively short. Likewise, if the existing charging infrastructure around ports of departure and arrival are relatively well built up, you probably want to consider DC-charging even on longer routes so that you provide a competitive alternative for land-based transportation and charging.   
Once the power demands have been identified, alignment with your vessel’s energy supply should be considered. Both technically and financially, it may appear to be straight forward to simply hook up the EV-charging system to your vessel’s electrical grid, but this means that you are supplying EV-charging power from the same source as for the vessel’s propulsion. Depending on your vessel’s energy source, this could pose two rather different problems: 
If your vessel runs on fossil fuels, exclusively or in a hybrid combination, your customers and other interested parties might find it morally problematic that EV’s are charged from a non-green source 
If your vessel is electric or running on other alternative fuels, you could be using a limited source of energy that should be dedicated to propulsion and ship safety, for EV-charging 
To align these issues with the identified power demands, several options can be considered. For instance, to ensure that propulsion power is always prioritized (for fully electric vessels) or that you can guarantee that EVs are charged only with green energy (for hybrid vessels), you can choose an on board EV-charging system that is integrated with your vessel’s power management system, so that the EV charging power can be automatically controlled in terms of energy source and capacity at any given moment of your operation. Alternatively, and for all types of vessels, you can consider an isolated on-board EV-charging system with an independent power supply, for instance a battery pack.  
@Marine Charging Point we can be of assistance in determining your specific EV-charging power demands and we offer various solutions for how to align these demands with your vessel’s energy source. 
Working at the intersection between maritime rules and EV-charging standards 
It should be no surprise to anyone working in the maritime industry, that electrical installations and hardware are covered by different standards and rules at sea and on land. As a general rule of thumb the maritime rules are stricter and the standards higher, than they are on land, this being due to the fact that an accident at sea is considered to have a higher potential for loss of life and/or cascading accidents, and because the marine environment is typically harsher on equipment than most land-based environments.  
As there are currently no maritime regulatory rules that applies specifically to on board EV charging, the direct implementation of a land-based EV-charging system on board a vessel is, technically, not illegal. There are, however, regulatory guidelines in place, for instance the European Maritime Safety Agency’s “Guidance on the carriage of AFV’s in ro-ro spaces” and the UK Maritime and Coastguard Agency’s Marine Guidance Note on “Electric vehicles onboard passenger roll-on/roll-off (ro-ro) ferries”; these guidelines are effectively applied by many Flag States and Classification Societies during the approval process of on-board EV-charging systems. Moreover, it is worth noting that these guidelines have been developed as a pre-legislation tool to assist interested parties in making on-board EV-charging safe and functional. In other words, the guidelines are not there to prevent on-board EV-charging, but to provide advice on how to implement on-board EV-charging safely and efficiently in advance of upcoming legislation. Following the advice and guidelines when implementing an on-board EV-charging system thus makes sense, not just for ensuring that the system is future-proof in expectance of future regulations, but also, importantly, because the advice is pretty sound in terms of upholding the necessary safety levels of a vessel as well as in terms of setting specific technical requirements for the equipment, to ensure it can withstand the specific, somewhat harsh use-context on-board a vessel. 
The guidelines (and notations) differ slightly from authority to authority, and should thus be considered from case to case, depending on which approving authority a vessel is governed by, but the main conclusion across the board is that the ingress protection grade of all EV-charging equipment should be at least IP56, which excludes a large section of equipment from the land-based sector. Moreover, and more significantly is the fact that even properly graded equipment has to be modified for marine use, so that vessel crew are able to monitor and control the EV-charging system both remotely and locally. On-board EV-charging system therefore has to be integrated with vessel IAS so that the charging process can be monitored and alarmed, in addition, local monitoring and/or control panels should be provided, none of which are options available with existing EV-charging systems.  
@Marine Charging Point we have sourced and developed on-board EV-charging systems that addresses all safety and functional features of relevance to the marine environment and the applicable guidelines. Our systems have so far been approved by two maritime authorities and one Classification Society and we can be of assistance in getting through the approval process. 
How to make your investment pay off 
On-board EV-charging creates an additional stream of revenue from day one, and it can also serve as a branding tool that can attract more customers in a competitive environment. Ultimately, after investments costs are paid off, it should also result in actual, direct profit. For this to happen, however, paying customers have to be aware of the possibility of on board EV-charging and they have to be able to partake of the possibility in an easy and efficient manner. Because on-board EV-charging is not fully public, but only available to customers who buy/book a ticket for transport, existing land-based charging maps are probably not the best option for advertising on-board EV-charging; instead it can be considered whether on-board EV-charging should be offered as an additional service that can be booked and/or paid for when customers book and/or pay their ticket for transportation. On the other hand, to be able to direct more traffic to vessels, integration of on-board EV-charging possibilities with existing travel planning applications for EV-drivers would also be relevant. Pre-paid EV-charging via a booking system can in turn be problematic, because it necessitates that the customer knows exactly how much power is required for their vehicle, that they end up overpaying for the service, or alternatively, that they do not receive enough power to avoid subsequently having to use a land-based EV-charging station to be able to continue their planned travel. Land-based EV-charging systems are typically based on membership applications (with or without roaming options), but such applications require a stable mobile or internet connection, which is not always available on all legs of a vessels journey.  
@Marine Charging Point, we have the experience needed to guide you in determining the best option for making on board EV-charging easy and accessible to the end-user, thus ensuring that an investment in such systems pay off.