BBC article on green flying

[Bald Rick]

If they arent put out they are suppressed during rescue I think
AIUI they use blanketing foam for fuel fires, but for batteries they would need vast amounts of water to attempt to restrain overheating spreading. Could they get that in the right place when the batteries would presumably need significant containment for the role (it gets a bit chilly at airliner height - would that overcome the heating caused by being used??).
That's one thing I don't like about battery fires - fuel burns in the open (needs air) so can be smothered whereas batteries can be igniting in the middle and generating their own oxygen. And generating their own oxygen means an inflight fire would be very unfortunate.
An airliner battery fire is going to make a real mess of the runway and be a very difficult clean up!

I supoose a key difference here is the physical properties of kerosene vs Batteries for fires on the ground.

30 tonnes of Kerosene will tend to spread itself around a fair bit - just watch Die Hard 2 for a detailed technical exposition

30 tonnes of batteries will be much more contained.

 

[AlastairFraser]

Slightly off topic perhaps, but you raise a good point about the South East airports. We see airports across the country, many crying out for more airlines services, claiming that they can relieve capacity on the congested airports in the South East. One which was doing so before it closed (and will no doubt do so again if it reopens) is DSA. However BHX also used that argument when they built their runway extension.

It’s nonsense. Global airlines want to fly to LHR, they aren’t even that bothered about LGW any more, certainly not STN or LTN which are mostly the domain of the big low cost and leisure airlines. If they can’t get into LHR they go to an airport on the continent. It’s about the hub and spoke network. So what is the answer? Well you either build the third runway at LHR, you build an entirely new airport somewhere near London (to the East perhaps), or you allow that traffic to migrate to another country.

Everything else is just noise. The third runway is being proposed with the promise of greater regional connectivity to LHR, much of which was lost when it started costing the same to run a Shorts 360 from my local HUY to LHR as it did to use a 747! Clearly that’s uneconomical, but domestic air travel doesn’t fit in well with environmental concerns. Conversely, making domestic air travel prohibitively expensive (and thus freeing up slots at LHR) isn’t going to generate many slots for other inter continental traffic or access to new markets.

It’s a mess, but I don’t see a way out of it. Maybe battery powered aircraft the size of ATR72’s could plug the U.K. regions into LHR and that could be the justification for building that third runway. But the technology has to exist first, and I don’t believe it does.

Could airlines that have less connecting passengers through Heathrow (e.g Uzbekistan Airways) could be financially incentivised to give up Heathrow slots when Gatwick's new runway opens, given Gatwick still has a reasonable selection of destinations to connect onto?

 

[Meerkat]

30 tonnes of batteries will be much more contained.

An article about Fire Services struggling with EV fires stated that one issue is that once battery packs are off and burning they start violently ejecting cells, such that the surrounding area, ditches, etc needed searching for them.
Re the large volumes of Kerosene - in dramatic crashes a lot of it gets left behind during the slide whereas batteries are likely to still be in the plane when it comes to rest (I’m assuming that as the structure supporting that kind of weight is going to be pretty solid)

 

[Peter Wilde]

I think that in the distant future there is, in theory, a way forward for those airlines who want to keep flying lots of people in big, long-range planes to large, popular airports (which are the ones like Heathrow that are close to major cities and have good ground transport to get passengers there).

But that solution seems a very long way off, if it is not to involve fossil fuels.

Why? This fully-green solution would be to make synthetic jet fuel - in large enough quantities.

There is not enough easy-to-use feedstock (waste cooking oil, etc) in the world to use that solution at scale, but my impression is it is technically feasible to make synthetic liquid fuels out of less energetic feedstocks - even including taking CO2 out of the air! The snag - such a route would require truly heroic amounts of renewably-generated electricity.

The alternative of using electric batteries in planes might in theory be more efficient - but for large airliners, will the enormous batteries ever be made light enough to give large airliners sufficient range? At the moment it seems unlikely.

The whole of the public debate on this subject is very liable to greenwashing. Not only by airlines (as in BA’s failed attempt a few years ago to set up its own token syn-fuel plant, scrapped for cost reasons); and the rest of the aviation industry. But also by those with an interest in hyping various experimental technologies, to secure research funding.

So in the short time the political choices may be between flight rationing (either by higher fares or some sort of quotas); better alternative options, like rail services; flight shaming, as in Sweden; or carrying on with token initiatives while climate change is allowed to ramp up unchecked. Not a happy choice! The last of these option is, of course, what is happening at the moment.

 

[Meerkat]

A cynic might say the airline industry is throwing out promised miracle fuels to put off restrictions until the rapid increase in flights in China/India/Africa etc has made it too popular to restrict.

 

[Peter Wilde]

Could airlines that have less connecting passengers through Heathrow (e.g Uzbekistan Airways) could be financially incentivised to give up Heathrow slots when Gatwick's new runway opens, given Gatwick still has a reasonable selection of destinations to connect onto?

Gatwick’s latest plans have not yet been decided on. If approved, there will be much protest. Its owners’ initial scheme (allegedly privately funded?) to convert its northern emergency runway/taxiway to become a fully open second runway has previously been accused of creating a "second runway by stealth”. One also wonders: if the present taxiway becomes a runway, and creates more flights, where would they build some extra taxiways? Residents and local authorities are pressing for its re-submission as a proper plan for a new second runway, to be subject to full normal scrutiny.

No idea what the new Government will make of this. On the one hand, they want to expand the economy and streamline planning processes. On the other, will they want to endure all the protests? And would they ever again be able to hold their heads up as "one of the good guys” in international climate negotiations, if they let such an expansion of aviation (up to 100,000 extra Gatwick flights a year, protesters claim) go through unchallenged? All very unpredictable and controversial.

Surely it would be much saner to deal with the little annoyances that prevent more use of HS1 (long-winded checks and check-in times; cramped facilities at St Pancras; trains not calling at Ashford, Ebbsfleet or Stratford; not encouraging a wider range of operators and services; etc). Then there would be much less need for domestic or short-haul European flights. That was what the Channel Tunnelwas meant to be for!

 

[Ediswan]

Gatwick’s latest plans have not yet been decided on. If approved, there will be much protest. Its owners’ initial scheme (allegedly privately funded?) to convert its northern emergency runway/taxiway to become a fully open second runway has previously been accused of creating a "second runway by stealth”. One also wonders: if the present taxiway becomes a runway, and creates more flights, where would they build some extra taxiways? Residents and local authorities are pressing for its re-submission as a proper plan for a new second runway, to be subject to full normal scrutiny.

The emergency runway could be upgraded, but it is too close to the main runway to use both at the same time.

 

[AlastairFraser]

Gatwick’s latest plans have not yet been decided on. If approved, there will be much protest. Its owners’ initial scheme (allegedly privately funded?) to convert its northern emergency runway/taxiway to become a fully open second runway has previously been accused of creating a "second runway by stealth”. One also wonders: if the present taxiway becomes a runway, and creates more flights, where would they build some extra taxiways? Residents and local authorities are pressing for its re-submission as a proper plan for a new second runway, to be subject to full normal scrutiny.

No idea what the new Government will make of this. On the one hand, they want to expand the economy and streamline planning processes. On the other, will they want to endure all the protests? And would they ever again be able to hold their heads up as "one of the good guys” in international climate negotiations, if they let such an expansion of aviation (up to 100,000 extra Gatwick flights a year, protesters claim) go through unchallenged? All very unpredictable and controversial.

Surely it would be much saner to deal with the little annoyances that prevent more use of HS1 (long-winded checks and check-in times; cramped facilities at St Pancras; trains not calling at Ashford, Ebbsfleet or Stratford; not encouraging a wider range of operators and services; etc). Then there would be much less need for domestic or short-haul European flights. That was what the Channel Tunnel was meant to be for!

There will be much protest, but the Heathrow plans will be a **** load worse. Gatwick's plans modify existing infrastructure to limit new land use, the airport is already directly connected to a wide range of regional and longer distance rail services, plus it has fairly decent road connections.

With Heathrow, it requires the destruction of an entire village, intercity services are difficult to access, and the surrounding roads are pretty jampacked (the M25 and M4 are much worse than the M23 usually, for example).

I agree that more use of the Channel Tunnel should be permitted, but for any fundamental changes in the economics of using both the CT and HS1 (border control provision is something that will be much easier to tackle as technological improvements exist), we need to nationalise both as the per passenger charge of the CT and the per km charge of using HS1 make increasing Eurostar frequency pretty difficult. Unfortunately, I don't see the government forking out for that any time soon, let's hope that new operators provide at least another service per hour in the interim (perhaps Evolyn from a base at Ebbsfleet!).

The emergency runway could be upgraded, but it is too close to the main runway to use both at the same time.

I thought the purpose of the upgrade was to increase capacity by a significant amount?
How will the upgraded runway do this if it cannot be used simultaneously?

 

[Bald Rick]

I think that in the distant future there is, in theory, a way forward for those airlines who want to keep flying lots of people in big, long-range planes to large, popular airports (which are the ones like Heathrow that are close to major cities and have good ground transport to get passengers there).

But that solution seems a very long way off, if it is not to involve fossil fuels.

Why? This fully-green solution would be to make synthetic jet fuel - in large enough quantities.

There is not enough easy-to-use feedstock (waste cooking oil, etc) in the world to use that solution at scale, but my impression is it is technically feasible to make synthetic liquid fuels out of less energetic feedstocks - even including taking CO2 out of the air! The snag - such a route would require truly heroic amounts of renewably-generated electricity.

Paging: contestant @HSTEd ; specialised subject….

Surely it would be much saner to deal with the little annoyances that prevent more use of HS1 (long-winded checks and check-in times; cramped facilities at St Pancras; trains not calling at Ashford, Ebbsfleet or Stratford; not encouraging a wider range of operators and services; etc). Then there would be much less need for domestic or short-haul European flights. That was what the Channel Tunnelwas meant to be for!

HS1 will do nothing for domestic flights; HS2 would for Glasgow and Edinburgh - had it been built in full - but would have removed something like 12 flights a day each way from Heathrow, and maybe 2 from Gatwick.

HS1 meanwhile has capacity for roughly double the number of international service compared to that run today (if there’s capacity through the tunnel), and as discussed at length on this forum, the number of destinations potentially served is relatively small, and the number of flights it would remove from Hesthrow / Gatwick also small. Perhaps another dozen a day each way. Put another way, combined (doing HS2 in full and doubling international services via HS1) would reduce Heathrow runway usage by about 3%, and Gatwick by maybe 2%.

== Doublepost prevention - post automatically merged: 11 Dec 2024 ==

I thought the purpose of the upgrade was to increase capacity by a significant amount?

Not a significant amount. The proposal has the northern runway used for ‘smaller’ departures (ie narrowbodies), with the southern (existing) runway used by ‘larger’ departures (ie widebodies) and all arrivals. This will help improve efficiency of arrivals and departures, enabling some more. But AIUI, only about 15-20% more.

 

[Ted633]

To give an idea of just how much electricity a large modern aircraft needs.

A 787 has 4 generators, each capable of supplying 250kva each. Fag packet calculations makes that around 6000amps available to power all the on board systems (Hydraulics, fuel pumps, air conditioning, IFE etc etc etc)
Obviously, this isn't yet required to power the engines themselves and I've no idea what the current draw on that would be. But to give a flavour, the Auxiliary Power Unit in the tail (very small jet engine to supply power on the ground ) has an electric battery start. This will draw almost 400 amps just to crank it over.

Unless there is a complete revolution in battery technology (weight/volume to capacity) large electric airliners are a complete non starter.

 

[AlastairFraser]

Not a significant amount. The proposal has the northern runway used for ‘smaller’ departures (ie narrowbodies), with the southern (existing) runway used by ‘larger’ departures (ie widebodies) and all arrivals. This will help improve efficiency of arrivals and departures, enabling some more. But AIUI, only about 15-20% more.

15 to 20 percent seems to be a decent amount that is proportionate to current aviation needs (especially if my proposal to make BHX a US preclearance hub draws a lot of the US traffic to a hub there ).

 

[HSTEd]

Why? This fully-green solution would be to make synthetic jet fuel - in large enough quantities.

There is not enough easy-to-use feedstock (waste cooking oil, etc) in the world to use that solution at scale, but my impression is it is technically feasible to make synthetic liquid fuels out of less energetic feedstocks - even including taking CO2 out of the air! The snag - such a route would require truly heroic amounts of renewably-generated electricity.

You are quite correct that the available renewable feedstocks like cooking oil etc are grossly insufficient to supply the ~15 million tonnes of jet fuel used each year in the UK.
The only available feedstock in these quantities is atmospheric carbon dioxide.

Direct air capture of carbon dioxide, then synthesis of hydrocarbons using Fischer Tropsch (FT) and electrolytic hydrogen is certainly possible. The technology (likely iron catalysed FT to use the carbon dioxide directly) dates from the 1940s.

The real problem is you need the equivalent of 30-40GW of continuous electrical output to make the hydrogen.
The amount is of similar scale to total UK electricity consumption today.

But the technology to do this does already exist.

 

[gabrielhj07]

Or reduce capacity and whack up prices, with most passengers rerouted via through ticketing on the railway.

If a government were to act in such a way, what do you suppose an airline would do with its now surplus aeroplanes? Leave them sat on the ground? No, they would just fly them to markets less hostile. So diddly squat has been achieved for the climate, while domestic travel has been made worse.

 

[Tetchytyke]

any fundamental changes in the economics of using both the CT and HS1 (border control provision is something that will be much easier to tackle as technological improvements exist), we need to nationalise both as the per passenger charge of the CT and the per km charge of using HS1 make increasing Eurostar frequency pretty difficult

It should never have been sold to the Canadian pension fund in the first place.

But high speed rail isn’t really the solution either. HS2 will be a net carbon producer, and that’s even if it’s used to full capacity (which I doubt). And high speed rail will never have the reach of aircraft.

Even in Europe, using high speed rail incurs a significant time penalty. London to Berlin or London to Barcelona both take about 8 hours, as opposed to about 2 hours on the plane.

 

[pug1]

It should never have been sold to the Canadian pension fund in the first place.

But high speed rail isn’t really the solution either. HS2 will be a net carbon producer, and that’s even if it’s used to full capacity (which I doubt). And high speed rail will never have the reach of aircraft.

Even in Europe, using high speed rail incurs a significant time penalty. London to Berlin or London to Barcelona both take about 8 hours, as opposed to about 2 hours on the plane.

Yes I’ve never understood this argument that rail can replace flights for longer range international travel. London to Paris/Brussels perhaps, but anyone making such journeys from somewhere like Leeds or Manchester would have no time savings over flying even with the hassle of getting to the airport and the airport processes that come with that.

What it can do is reduce the need for domestic flights if implemented correctly. I still find it a hassle travelling by rail to LHR, because I can’t get a train to LHR so it’s a train to Kings Cross and either a transfer to Paddington for the express or a very long tube ride!

 

[Ediswan]

To give an idea of just how much electricity a large modern aircraft needs.

A 787 has 4 generators, each capable of supplying 250kva each. Fag packet calculations makes that around 6000amps available to power all the on board systems (Hydraulics, fuel pumps, air conditioning, IFE etc etc etc)
Obviously, this isn't yet required to power the engines themselves and I've no idea what the current draw on that would be. But to give a flavour, the Auxiliary Power Unit in the tail (very small jet engine to supply power on the ground ) has an electric battery start. This will draw almost 400 amps just to crank it over.

This role has been covered by batteries for decades and is only for the short period required to start the APU.

 

[Ted633]

This role has been covered by batteries for decades and is only for the short period required to start the APU.

Fully aware of that. Was just mentioning to give some comparison of how much power a battery would have to supply to continuously power a jet engine on an all electric design

 

[edwin_m]

HS2 will be a net carbon producer,

It was said in the early 2010s that HS2 would be broadly carbon neutral in operation, but since then the UK energy grid has been decarbonised to a large extent. Is that statement true today?

 

[AlastairFraser]

If a government were to act in such a way, what do you suppose an airline would do with its now surplus aeroplanes? Leave them sat on the ground? No, they would just fly them to markets less hostile. So diddly squat has been achieved for the climate, while domestic travel has been made worse.

Well, for example BA is in the process of retiring a lot of their older fleet and is trying to reduce their cost base, so they could reduce their A32x Neo series order a bit and order an initial ten electric/hydrogen turboprops instead.

It should never have been sold to the Canadian pension fund in the first place.

But high speed rail isn’t really the solution either. HS2 will be a net carbon producer, and that’s even if it’s used to full capacity (which I doubt). And high speed rail will never have the reach of aircraft.

Even in Europe, using high speed rail incurs a significant time penalty. London to Berlin or London to Barcelona both take about 8 hours, as opposed to about 2 hours on the plane.

The frequency of routes like e.g. London to Geneva could make a big dent into what you can capture. Yes, it's true that modal shift on a much grander scale would mean much bigger interventions.

 

[gabrielhj07]

Well, for example BA is in the process of retiring a lot of their older fleet and is trying to reduce their cost base, so they could reduce their A32x Neo series order a bit and order an initial ten electric/hydrogen turboprops instead.

Why would they do that? Leaving aside the fact that such an aeroplane doesn't exist, why would BA order something that they'd have next to no use for, and which would significantly raise their operating costs?

 

[Tetchytyke]

It was said in the early 2010s that HS2 would be broadly carbon neutral in operation, but since then the UK energy grid has been decarbonised to a large extent. Is that statement true today?

The carbon cost of the construction undoes all of the carbon savings from operation.

 

[edwin_m]

The carbon cost of the construction undoes all of the carbon savings from operation.

Evidence?

 

[Tetchytyke]

Evidence?

Will HS2 really help cut the UK’s carbon footprint?

The high-speed rail project has become one of the most costly and controversial of the modern era – and may not even be good for the environment

www.theguardian.com

The government’s own calculations for HS2 suggest its carbon emissions could exceed potential savings, even over the railway’s projected 120-year lifetime.

HS2 will not cut carbon emissions. According to HS2’s own forecasts, even over 120 years, its overall construction and operation cause carbon emissions of 1.49m tonnes of carbon dioxide equivalent. This represents just 1.18% of Britain’s annual transport emissions, but critics say it is still an increase when emissions need to be falling rapidly to reach net zero.

HS2’s construction requires vast quantities of concrete and steel, as well as diesel-powered machines moving millions of tonnes of earth.

Of course the picture may change if there's more modal shift than anticipated or if we get more of our electricity from non-carbon sources in the future. But as it stands the construction process emits huge quantities of carbon and the savings from operation won't be enough to cover those emissions.

 

[AlastairFraser]

Why would they do that? Leaving aside the fact that such an aeroplane doesn't exist, why would BA order something that they'd have next to no use for, and which would significantly raise their operating costs?

It helps their ESG plan, if not anything else.

 

[edwin_m]

Will HS2 really help cut the UK’s carbon footprint?

The high-speed rail project has become one of the most costly and controversial of the modern era – and may not even be good for the environment

www.theguardian.com

Of course the picture may change if there's more modal shift than anticipated or if we get more of our electricity from non-carbon sources in the future. But as it stands the construction process emits huge quantities of carbon and the savings from operation won't be enough to cover those emissions.

Thanks for that. It's from 2020 so there might have been further decarbonisation of the power grid since then. However, the cancellation of sections of it has probably reduced the benefits more than it has reduced the embodied carbon, so may well have made it worse overall.