carbon related

Feb 9, 2016

Budget carrier easyJet plans to turn Airbuses into Priuses

An easyJet/Cranfield University proposal to use a hydrogen fuel cell to haul its jets around taxiways to save fuel and fossil carbon emissions comes with numbers that could mean big

Ben Sandilands — Editor of Plane Talking

Ben Sandilands

Editor of Plane Talking

An easyJet A319, maybe not so easy on the eyes in its new livery
An easyJet A319, maybe not so easy on the eyes in its new livery

An easyJet/Cranfield University proposal to use a hydrogen fuel cell to haul its jets around taxiways to save fuel and fossil carbon emissions comes with numbers that could mean big savings on short haul routes like Sydney-Melbourne.

Just getting into position for takeoff can take an inordinate amount of time compared to the interval between lift off and touch down between close city pairs.

On some SE Australian flights the block time of 55 minutes or so for the actual flying comes with an extra 20-25 minutes of queuing and taxying depending on the congestion factor, making some trips slower than they were when Locheed Electra four engined turbo-props ruled in the early 60s.

Who hasn’t wondered, ‘Are we there yet’ when a flight to Melbourne from say the Qantas domestic terminal at Sydney is sent via that wonderfully daft and devious set of turns along taxiways to the far end of the third runway for a northerly departure.

These issues can be much worse on some European flights, which is where easyJet is hard at work undermining the likes of Lufthansa and BA with lower fares and roomier seats for those who pay for select rows on their jets compared to their legacy competitors.

The focus of the easyJet/Cranfield study is to replace the inefficient burning of fuel during the ground phase of a flight with electrical power stored in a hydrogen fuel cell routinely recharged by capturing the some of the energy wasted when the brakes are applied on landing.

There is more detail on this here.

The capture of such energy by fly wheels has been incorporated into some trolley cars and trucks for around 100 years, including in a pre-war trolley bus fleet in the Sandringham area of Sydney near its airport. Recovering part of the energy used to accelerate an automobile when it brakes has been integral to current and recent hybrid car designs.

The cost versus cash benefits of such designs has however been long disputed, and such technology is often seen as working best in a tax advantage or regulatory emissions reduction context where the rules reward such investments.

EasyJet will also have to get certification for such a modification, and practice tells the airline business that jet makers like Airbus or Boeing are needed to get on board to make such changes as intended at the regulatory and operational level.

It’s not as simple as the article in Business Traveller might suggest. The easyJet/Cranfield plan is also but one of many such proposals, including various studies aimed at similar outcomes by Airbus and Boeing.

But the potential savings to airlines, and the contribution that would be made to reducing emissions of fossil sourced carbon particularly in the case of short frequent flights could be very worthwhile.

(Visited 2 times, 1 visits today)



Leave a comment

8 thoughts on “Budget carrier easyJet plans to turn Airbuses into Priuses

  1. Tango

    I think there are at least two test systems out there.

    I just don’t think that flywheels are a correct application here.

    the best one has been garbage trucks where there is a lot of start stop ops and some construction machinery it works for.

    something that picks power off the APU or even engine on one side.

    The other aspect is how many flights get to the Runway, power up the engine or engines and find there is a turn around fault?

    Not simple indeed.

    How much warm up time does a jet engine need?

  2. Ben Sandilands

    The reference to fly wheels for stored energy was purely historic. Hydrogen fuel cells weren’t even on the horizon when trolley buses ran to Sandringham, and international movements through the Rose Bay flying boat base probably exceeded those from Kingsford Smith (Sydney).

  3. Roger Clifton

    Sounds like more junk to be airfreighted around the world. How about autonomous tugs that return to their recharging points after delivering each heavy to its runway? It would also remove the task of ground navigation from the cockpit to the tower.

  4. derrida derider

    Roger’s right – the easy solution is an unmanned tug. But not autonomous – you’d have terrible trouble getting safety certification for that (“what if it wandered onto the runway?”).

    A simpler solution would be to have the tug connected by a retractable (from the tug) lead and controlled by the PF. It could then be fail-safe – when the connection is broken the tug stops. About every tenth takeoff someone drives out and collects the discarded tugs from their designated dropoff area near the start of the runway – like collecting supermarket trolleys.

  5. NiallOC

    Hydrogen fuel cells? Why does everyone always, throughout time, think that they are the solution to every problem. They were invented in 1838, so aren’t exactly new. The trouble is that hydrogen is a really poor fuel. Also, would you like highly compressed (200bar+) hydrogen on your plane?

  6. Ben Sandilands

    NiallOC has a point, but due to poor wording in the original item I linked to, as in hydrogen fuel cell. These are for storing and liberating electrical energy over a shorter period, not for burning the hydrogen, although as Apollo 13 proved, they can explode.

    There was a celebrated briefing, possibly before 2000, by BMW about the difference between hydrogen fuel cells and hydrogen as a fuel, which it did put into some of its cars in Germany at least for a while.

    The punch line was that hydrogen as a fuel worked if it was rendered a super critical fluid, neither gas nor liquid, which required about something incredible like a pressure of maybe 700 atmospheres to render sufficiently dense to be useful except for the monstrous assemblage to contain it so that a light fender bender in traffic didn’t destroy a city block. The motoring media was told that at such pressures, even custard would be deadly.

    BMW did set up a small chain of liquid H service centres for a limited run of dual hydrogen and petrol cars but it clearly never caught on.

  7. AvroAnson

    “…although as Apollo 13 proved, they can explode”.

    If I remember correctly it was the oxygen tank which failed on Apollo 13. Maybe we should ban oxygen in aircraft?

    I think the concept of small tugs (whether autonomous or otherwise) is probably a better solution to the problem. No additional mass to be carried in flight, and of course all aircraft (up to the tug’s load limit) would benefit. There are of course a host of practicalities to be addressed in any such scheme.

  8. Dan Dair

    “There are of course a host of practicalities to be addressed in any such scheme”…..

    Not least, whether it is time-effective to tow an aircraft out to (or back from) the end of a runway.?
    If an ‘electric’-tug could tow an aircraft to (& from) the end of the runway as time-efficiently & more cost-effectively, I’d be bullying the tug-manufacturers to get to it right away.!

    I presume that there would be no type-certification required for this.?
    The airports would obviously need to be on-board with the plan, but at least if the tug failed, the aircraft could power-up its engines & trundle off by itself.!!!

    Providing the tugs are not horrendously expensive (& why should they be.?), their costs would probably be more than offset by the reduced wear & tear and maintenance on the jet engines.

    The fuel-savings would make the whole thing worthwhile
    & if the power could come from renewables or non-carbon-releasing it would be the icing-on-the-cake.

Share this article with a friend

Just fill out the fields below and we'll send your friend a link to this article along with a message from you.

Your details

Your friend's details