Electric Cargo Ships: Why Haven't They Happened Yet?

Electrification of cargo ships is something that futurists have been touting for a while. Even back in 2016 when it was clear that battery technology was improving, the idea was presented to industry. 

But, of course, there are hardly any electric boats, let alone any transporting containers across the Pacific and Atlantic Oceans. 

The question is, why didn’t this technological revolution happen?

The Enormous Energy Demands

One problem is the sheer energy demanded by many of these cargo ships. Container vessels and bulk cargo carriers need so much fuel to get them around the planet, and it simply isn’t possible to store that in batteries. 

For example, many ships require a marine water pump to pump seawater over the engines to keep them cool. This alone is an energy hog. Combine that with all the other components and you have a system that requires tremendous energy input to keep it stable. 

Battery Weight Constraints

Another issue that many people don’t consider is battery weight constraints. Even the most advanced batteries can’t match the energy density of diesels and fuel oils used in the shipping industry, meaning that they wouldn’t be able to carry as much cargo. 

As an example, the average large transport or cargo ship would require 10 tons of batteries for every 1 ton of fuel replaced. This ratio would make the entire ship unwieldy, and could even put it at risk of sinking to the bottom of the ocean. While smaller ships going shorter distances might be able to get away with it, ocean-going vessels cannot. 

High Upfront Costs

The high upfront costs of a lot of batteries for an ocean cargo ship is also prohibitive. These vessels would need the same battery power as thousands of regular road vehicles. 

For ship owners, these additional costs are impossible for them to absorb on their tight margins. As such, most electrification projects don’t go ahead on the high seas. 

Slower Regulatory Push

The regulations for what power sources you can use on the ocean are different. Unlike on land where the environment is a top priority, the same is not true at sea. The open oceans aren’t a part of any country’s territory, so most shipping firms simply find the cost-effective version for doing what they want to do, and run with that. 

Competing Alternative Fuels

Lastly, there isn’t really much point for shipping companies to invest in battery technology for their vessels. These days, there are so many alternative fuel sources and options in development that opting for electricity as the means to propel a ship feels risky. 

For example, consider that a lot of companies are now trying to power ocean-going vessels with substances, like ammonia. These wouldn’t necessarily work on land, but they do work on the open ocean, far from people. 

Downtime

Finally, batteries have downtime, meaning that shipping companies would often need to wait for them to charge. Diesel doesn’t eliminate this problem entirely, but it is a lot faster to refill and get back out on another transport trip.