Shipping moves 90% of global trade and produces nearly 3% of global emissions. The sector has proved challenging to clean up, as cargo ships can travel for weeks between ports and typically rely on cheap, energy-dense and extremely polluting heavy fuel oil.

Earlier this year, international efforts to move shipping towards net zero by using cleaner fuels fell apart under pressure from the United States. But as battery prices fall year on year, there might be another way forward.

Electric ferries already shuttle passengers and cars on short routes, while harbour tugs and inland cargo vessels are also going electric. At present, electrification works best over modest distances where charging can happen at the dock.

Could it ever work for container ships crisscrossing oceans? These giants can travel from China to Europe without refuelling due to the energy density of oil. The weight and expense of battery packs means it would be hard to swap oil for batteries.

But electrification isn’t all or nothing. Batteries would need to begin by operating alongside liquid fuels. In

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