Boeing has unvieled a new prototype unmanned aerial vehicle (UAV), or spy plane to you and I, called Phantom Eye which runs on hydrogen fuel. While this strange-looking aircraft will not be used for commercial flights, we often get questions such as “when will we be flying on hydrogen-powered planes?”.

The answer is: “no time soon”. While hydrogen is a great, clean, fuel source, it’s main problem is the volume of fuel required. Compared to our current fuel, or the biofuel we will be using in the coming years, hydrogen has a lot less ‘power’ for each litre of fuel – and therefore a lot more needs to be carried. In effect, you’d almost need to replace the whole lower deck of an A380 with fuel tanks to power a flight of any reasonable length.

This is not to say that hydrogen might not have some benefits and projects like the Phantom Eye and Boeing’s hydrogen fuel cell are providing much-needed insights into the use of such fuels.