Aircraft

Drone flight powered by lightweight hydrogen-producing pellets

Drone flight powered by lightw...
The hydrogen-powered drone takes to the Scottish skies
The hydrogen-powered drone takes to the Scottish skies
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The hydrogen-powered drone takes to the Scottish skies
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The hydrogen-powered drone takes to the Scottish skies
Although the flight only lasted 10 minutes with the drone cruising at an altitude of 80 m (262 ft), the cell reportedly had enough fuel to fly for two hours
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Although the flight only lasted 10 minutes with the drone cruising at an altitude of 80 m (262 ft), the cell reportedly had enough fuel to fly for two hours
The flight was carried out on Jan. 19th at Scotland's Oban Airport, by a team from the Scottish Association for Marine Science (SAMS)
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The flight was carried out on Jan. 19th at Scotland's Oban Airport, by a team from the Scottish Association for Marine Science (SAMS)
The fuel took the form of approximately 100 small solid pellets contained within an unpressurized cartridge
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The fuel took the form of approximately 100 small solid pellets contained within an unpressurized cartridge

At first glance, hydrogen fuel cells sound like a great power source for fixed-wing drones making long flights – they have much longer run times than batteries, and they emit no emissions other than water vapor. Unfortunately, the hydrogen typically has to be stored in large heavy pressurized tanks. Last month, however, a Raptor E1 electric drone made a successful test flight running on a unique new system that's actually lighter than the lithium-ion battery it replaced.

The flight was carried out on Jan. 19th at Scotland's Oban Airport, by a team from the Scottish Association for Marine Science (SAMS). Although the flight only lasted 10 minutes with the drone cruising at an altitude of 80 m (262 ft), the fuel cell reportedly had enough fuel to fly for two hours.

That fuel took the form of approximately 100 small solid pellets contained within an unpressurized cartridge. Made by Britain's Cella Energy, those pellets are composed of a proprietary chemical compound, and they steadily produce hydrogen gas when a small amount of heat is applied. The Arcola Energy-manufactured fuel cell converts that gas into electricity, which was used to power the drone's motor.

The fuel took the form of approximately 100 small solid pellets contained within an unpressurized cartridge
The fuel took the form of approximately 100 small solid pellets contained within an unpressurized cartridge

According to Cella, the pellets (which measure 1 sq cm each) are stable during rough air travel, and at temperatures as warm as 50º C (122º F). Pressurized hydrogen, by contrast, must be stored at very low temperatures.

"This flight used a small prototype system and we were pleased with the initial flight, with another flight scheduled to take place in the near future," says Cella's Managing Director, Stephen Bennington. "The larger versions of this system that we are already designing will have three times the energy of a lithium-ion battery of the same weight."

Ultimately, the technology may even be integrated into full-size passenger-carrying aircraft.

Source: Cella Energy via New Scientist

15 comments
BartyLobethal
Intriguing development. If it works for aircraft, it will work for cars. At the least, this radically changes the required re-fueling infrastructure.
Bob
Lots of questions here. Why only make a 10 minute flight if you had enough fuel for two hours? Are these new pellets metal or nonmetal hydrides? Or is the breakthrough just the fuel cell? And lastly whatever happened to fuel cells that could run on gasoline or ICE engines that run on pure hydrogen rather than converting it to electricity to power an electric motor?
Jimjam
There is no way to produce pure enough hydrogen in a way that is cheap enough for use in cars. Electrolysis of water is the only current method that produces hydrogen pure enough not to foul the fuel cell membrane. Reforming methane (natural gas) produces hydrogen that is too dirty for use in fuel cells. This could definitely have applications in aviation or drone use (particularly military where cost is less of an issue).
johanschaller
Bob, clearly, as the pellet material is a proprietary compound, the inventors are understandably coy about describing it in any kind of detail. And if the text wasn't clear enough, the hydrogen-containing pellets are definitely the focus of this article. Regarding flight time, in any experiment you certainly don't try to test all possible variables at once. As this drone is not some toy-store item, but a serious aircraft, it would be stupid to "see how long it will fly for", and most likely end up trashing the craft.
Anne Ominous
To Bob: Also, it is not true that hydrogen cannot be produced cheaply enough to drive cars. It most certainly can. The problems, and major cost and performance issues, are not related to PRODUCING it. Rather, they are with storing and transporting it. Storage is relatively risky, and SAFE storage is relatively heavy. Transporting it is likewise difficult and (relatively) dangerous, plus there is the difficulty of transferring it from one storage container to another. (I.e., from storage tank to rail or truck, from truck to fuel station, from fuel station to automobile.) Further, hydrogen represents a large amount of usable energy by weight, but not so much by volume. Even liquified, it takes a lot of hydrogen to go very far in a car.
vbillc
Let's go back to the 19th century and use water, carbide and acetylene
Marc Browne
They mentioned that it was lighter than lithium-ion but not if it had a higher energy density. A Tesla has a lot of batteries for a relatively (compared to ICE) short range, if the energy density is a lot lower than lithium-ion then the vehicle size would be prohibitive. Hopefully not though!
Mel Tisdale
If nothing else, this system would make a good range extender for electric cars and thus take away one of the major drawbacks that they have. As for the application itself, how big are the pellets by volume i.e. one square centimetre by how long? And what is their shelf-life?
Bob Stuart
It is finally becoming clear that the way to store hydrogen is one atom at a time, not in bulk. External containment only is generally insufficient. AFAIR, there are more hydrogen atoms in a gallon of water than in a gallon of liquid hydrogen, so high density without strong bonding is probably the new challenge.
Bob
To my critics, I questioned the short flight time because any good RC operator would have had no problem keeping the model up for a more impressive test flight unless there were other problems with sustaining the hydrogen production. Reporting a two hour flight would have been much better press than 10 minutes. Why didn't they prove it? A little more performance information about the so called proprietary pellets would have been nice. Otherwise this story smacks of more hype than substance. And lastly, as a chemist who has worked with the metallurgy of containing hydrogen, I have found it far more dangerous than anybody selling the idea of hydrogen powered transportation wants to admit. It is explosive in any range from 10-90% with the ability to embrittle and permeate many metals, even the hydride forms present risks. Leaks are always a problem and hard to detect. Hydrogen power can have many useful applications but it's safe use must be monitored closely.