Believe it or not, that modern-looking tin can in the sky you're flying — with its touchscreen TVs at every seat — most likely took flight for the first time decades ago. All of those fancy electronics are upgrades sucking on outdated power systems. That's why these trolley carts were created to deliver a different kind of juice.
Researchers at the Fraunhofer Institute for Chemical Technology ICT have developed a trolley-sized fuel-cell generator that planes can safely carry for extra power with minimal upgrades. By making the generators the same size as the food trolleys, it guarantees that any large plane can already accommodate them. The compact generators also mean that as plane cabins are continuously upgraded over the years to incorporate new tech to make us comfy, the rest of the plane doesn't need really expensive upgrades, like more powerful turbines, to keep up with the extra power demand.
But since recharging such a large battery would take hours — much longer than an aircraft's turnaround time — the Fraunhofer Institute researchers instead opted for a fuel-cell based system. The most common fuel used these days is straight-up hydrogen, but it needs to be stored in pressurised containers which can be a safety risk aboard planes. So in this case, propylene glycol is used. It doesn't require a pressurised container, and it produces carbon dioxide as a by-product, not deadly carbon monoxide. So across the board it's a safer alternative, and it's easy for maintenance crews to quickly swap in a new bottle of fuel before each flight. [Fraunhofer Institute]