Is a battery powered container ship possible?
The automobile industry joins the challenge of providing alternatives to combustion engines by 2030. Governments also join the idea of zero emissions in their main urban centers. The 2030 agenda is imposed (the one that says who pollutes and who does not) as a step to reach the emission targets accepted in Europe and in the first world (China, Russia and others, of course not) by 2050.
Electrification in the individual means of transport is therefore a fact and is reaching a limit point. Society looks towards other sources of pollution, and questions itself logically why not do the same with maritime transport (responsible for 3% per year of total greenhouse gas emissions on the entire planet).
There are a few examples of energy electrification around the world.
The vessel Yara Birkland (7MWh/14 Knots) got into tests along 2021. The small tanker e5 test in short. Developments are being added that seek to advance experimentation and provide data for subsequent regulation.
But…Is there a limit?
To analyze this variable, let’s suppose that it is proposed to electrify the propulsion plant of a container ship type of 18,000 TEUs, the usual size used in intercontinental traffic (ASIA – EUROPE) that uses 31 days of navigation powered by a Diesel engine (one of the largest), with a consumption of 4,650 Tons (HFO).
The specific density or energy density for Fuel oil turns on 11.700 Wh/Kg. Ion-lithium gets a value of 300Wh/Kg. 40 times bigger for Fuel.
The total fuel consumption means 195 Tera Jules or 54 gigawatts-hour. As Diesel efficiency is 50% the demand power is 27 Gigawatts-hour. Leaving 20% of power on cell batteries means that battery weight goes to 110.000 Tons.
And what does this mean for the operation of an 18.000 TEU ship?
The container ship CNA CGM BENJAMIN FRANKLIN has death weight of 185.000 Tn. This means a reduction of cargo capacity of 60%. Huge!
Switching from fossil energy to electricity / batteries in a ship like the one analyzed in this example is for now a pipe dream.
As it happens with electric cars (where a battery weighs about 500 Kg and represents almost 24% of the total weight), the problem is complicated when we transport cargo where all the weight (including that of the batteries) counts for the final performance. (There we see the problems of TESLA with trucks!).
The solutions go through adapting to hybrid solutions (such as Toyota with the Prius) adjusted to displacements of limited autonomy and combined cycles. And this is so because the specific energy of fuel oil (44 Mj/Kg) is currently unbeatable. It would be necessary to multiply the specific energy of the batteries by 70 to equate them to fuel oil.
For the record specific energy or density energy of uranium ( nuclear burning) is 3.450.000 Mj/Kg….but this is another story!