Green Trains, ie Carbon Neutral

[Damo666]

Listening to BBC Any Questions on Radio 4 last night (Fri 31st Jan 2020) Lord Mann said (in response to a question on HS2) that for freight we should be using "Green Trains, ie: Carbon Neutral; using Quiet trains..... That's within our technological grasp right now".

 

BBC4 AQ Timed at 36:50

 

Is this correct?
Are there such things as Green Trains?

or Carbon Neutral Trains?

or Quiet Trains? (What's the definition of quiet, apart from another get-out clause politicians can rely on)

 

I know the 'within our technological grasp right now' is also a bit of a get-out clause, but interested to know if this is just another example of political statements made-up to win an argument on-air and not being challenged by journalists.

[keefer]

100% electric railway (with power coming from carbon-neutral or renewable generation) and the fitment of/capacity to fully operate on-train regeneration & any 'last mile'/shunting diesels to run on bio-fuel - I think that's pretty achievable and not even using the latest hi-tech available.

Whether it will ever happen is debatable given how recent electrification projects have had the tendency to go badly wrong for one reason or another.

As to quieter trains there will always be noise, much of it coming from the wheel/rail interface and just the action of moving! Unless the whole railway goes mag-lev or on rubber tyres.

[iands]

Quiet Trains? Interesting comment. Obviously Lord Mann hasn't heard a class 68. A couple of weeks ago I happened to be heading to London from York, and whilst waiting for my train a Scarborough-Liverpool service headed out and I commented to my boss how loud the 68 was (actually quite deafening. And a couple of days later on our local news (Look North) there was a story about complaints from Scarborough residents on being woken at 4.30 every morning by the start up of locos since the 68s were introduced. Quiet trains may well be "within our technology grasp", bit it certainly hasn't been applied in the class 68 programme.

 

Edit: Just re-read the original post and realised that Lord Mann was perhaps referring to electric traction - point taken. However, my comment on the 68s remains. A 66 (IMO) is nought but a whisper in comparison to a 68.  

Edited February 1, 2020 by iands

[keefer]

Even modern electric trains seen to make way more noise than older 'classic' stock, but this is mainly due to the AC drives/electronics used to power them - some of them even play a scale as they pull away!

[Foden]

58 minutes ago, keefer said:

Unless the whole railway goes mag-lev or on rubber tyres.

Rubber tyres on the prototype, after years of complaining and protesting of un-prototypical rubber tyres on the model.

 

How charmingly ironic that would turn out to be!

[Nearholmer]

Rubber tyres are the enemy of energy efficiency, so quiet but in-green.

 

An electric railway powered by hydro-electricity gets probably as close as possible to genuine carbon-neutrality, although it might need to plant a lot of trees to make up for emissions during construction.

 

The technology necessary has been available since about 1883, and has even been used within these isles to a limited extent, a long time ago. The ordinary thing to do in mountainous districts, of course, and is what lies behind the odd frequency (16.67Hz) used for a lot of electrification on the continent.

 

Most of the UK isn’t well-placed for hydro though, so grabbing every other source than fossil fuels is probably the way forward, as is storing energy to tide-over (maybe a pun there) between periods of high availability and high demand.

 

Once you move away from wired (in the broadest sense) electric, to things like battery and fuel cells, it gets increasingly difficult, because conversion efficiencies are not all that good, and the mass and/or volume of the storage medium can become a limitation.

 

 

Edited February 2, 2020 by Nearholmer

[Ben B]

Carbon Neutral?  Either the passengers power the trains like the cars in the Flintstones (meeting Govt targets on getting us all healthy at the same time, bonus), or drag the preserved Jinty tank locos out from the KWVR, MR(B)… they've got those big keyhole-openings in the sides, clockwork-power would be about as green as you could get

[corneliuslundie]

I wonder how "green" batteries are, with the energy and rare elements used to make them and their limited lives and then need for disposal. This is not a statement. I just don''t know because it rarely seems to be mentioned.

Jonathan

[keefer]

Not too mention the inter-continental distances between the source materials and manufacture, and the particularly toxic nature of the processes involved.

The biggest carbon footprint of any vehicle is that of its manufacture, before it has even moved.

[Edwin_m]

4 hours ago, Nearholmer said:

The technology necessary has been available since about 1883, and has even been used within these isles to a limited extent, a long time ago. The ordinary thing to do in mountainous districts, of course, and is what lies behind the odd frequency (16.67Hz) used for a lot of electrification on the continent.

At the risk of going off-topic, I don't think it's a direct causation as you imply.  Early schemes could either generate and use DC, not very efficient, or use AC at a higher voltage with transformers on the train.  However at that time the only viable (variable speed) motors for traction applications would overheat at higher AC frequencies, and the alternative of on-board rectification wasn't possible either.  I'm not sure if similar frequency limitations applied to generators - possibly not as they would have run at constant speed - but if they did then the restriction would have been the same regardless of what was turning them.  

[Nearholmer]

The very earliest hydro-electric railway schemes did indeed generate, distribute and use at relatively low voltage dc, but that wasn’t viable for schemes over any distance or of any substantial power. Hydro offered the possibility of schemes of substantial size/power, but only if HV ac transmission was used, and in the absence of a viable means to rectify on board the trains that necessitated a ‘low’ frequency to avoid excessive arcing at the commutators of the only available types of traction motor.(unless you opted for a Kando-type design of motive power, which is horribly complex for most purposes).

 

I think, but would need to double-check, that at the very outset of such schemes the option of line-side rectification (rotary converters) wasn’t fully on the table either, so they couldn’t go to,say, 1.5KV dc as a lot of somewhat later schemes did.

 

So, what I’m contending is not that hydro forces low frequency (it clearly doesn’t), but that the ready availability of hydro resources is what drove railway electrification on the continent, it was too good a resource to miss out on, at a time when the only viable way to electrify was ‘low’ frequency ac. And, it’s stuck ever since. It is what lies behind the current situation.

 

 

 

 

Edited February 2, 2020 by Nearholmer

[Davexoc]

6 hours ago, Nearholmer said:

An electric railway powered by hydro-electricity gets probably as close as possible to genuine carbon-neutrality, although it might need to plant a lot of trees to make up for emissions during construction.

 

Therein lies the problem, everyone jumps on the zero emmissions part of the story. The alternative construction can have a massive impact on the true 'green' credentials.

 

5 hours ago, corneliuslundie said:

I wonder how "green" batteries are, with the energy and rare elements used to make them and their limited lives and then need for disposal. This is not a statement. I just don''t know because it rarely seems to be mentioned.

Jonathan

 

Pretty sure I remember reading somewhere that something like a Nissan Leaf will not be greener than a similar combustion engine powered vehicle until well after year 3, and if in that time you have to replace the battery, even longer.

[Edwin_m]

14 minutes ago, Nearholmer said:

The very earliest hydro-electric railway schemes did indeed generate, distribute and use at relatively low voltage dc, but that wasn’t viable for schemes over any distance or of any substantial power. Hydro offered the possibility of schemes of substantial size/power, but only if HV ac transmission was used, and in the absence of a viable means to rectify on board the trains that necessitated a ‘low’ frequency to avoid excessive arcing at the commutators of the only available types of traction motor.(unless you opted for a Kando-type design of motive power, which is horribly complex for most purposes).

 

I think, but would need to double-check, that at the very outset of such schemes the option of line-side rectification (rotary converters) wasn’t fully on the table either, so they couldn’t go to,say, 1.5KV dc as a lot of somewhat later schemes did.

 

So, what I’m contending is not that hydro forces low frequency (it clearly doesn’t), but that the ready availability of hydro resources is what drove railway electrification on the continent, it was too good a resource to miss out on, at a time when the only viable way to electrify was ‘low’ frequency ac. And, it’s stuck ever since. It is what lies behind the current situation.

Agreed.  But if the technology allowed the low-frequency AC to power a motor on the train then it could equally have powered a rotary converter, and DC generators were known technology, so DC traction would have been equally possible.   I suspect they were thinking of a main-line rather than a suburban railway and 15kV offered the best all-round solution available at the time (including, in an attempt to get back on topic, energy efficiency) just as 25kV did later.  

[Nearholmer]

16 minutes ago, Edwin_m said:

then it could equally have powered a rotary converter,

My point is that these railways were up and going before the combination of line-side rotary converter and medium voltage distribution to a loco with dc traction motors was viable for truly heavy main line traction (it was viable for metros by c1900).

 

I’ve now got Duffy to hand, and he says (p122) “The normative HVDC using a single trolley wire ........USA, in 1913”, and he discusses examples which were initially electrified using ac OHLE and ac motors, and shortly afterwards converted to 1.5kV dc using rotary convertors.

 

Nearly on topic, he ends the section (p129) with a paragraph starting “One point must be stressed. These early electric main line railways were only economic if they were supplied from hydroelectric stations.”

 

 

Edited February 2, 2020 by Nearholmer

[The Stationmaster]

Some examples from Switzerland -

 

Wengernalp Bahn Electrified June 1893.  DC powered averah ge contact wire voltage 1500v

 

Jungfrau Bahn.  Opened September 1898 3 phase ac 50Hz, average contact wire voltage 1125v (originally operated at 500volt at teh contact wire, then increased to 725v and finally to 1125v).

 

Cornergrat Bahn  Opened August 1898, as Jungfrau Bahn but average contact wire voltage 725v

[Dave John]

Well, there are many rubber tyred metro systems around the world. They are quieter and better able to handle gradients than steel on steel, but have higher rolling resistance so are less efficient. I would also suggest that stability at high speeds might be a limiting factor. 

 

https://en.wikipedia.org/wiki/Rubber-tyred_metro

 

But back to the op. Carbon neutral ? So not only does the energy to run the trains over their whole lifetime have to be generated in a carbon neutral way but also all the embedded energy in the materials and methods to build the railway.  Would that also have to compensate for all the historic embedded energy if existing infrastructure is used ? 

 

Fine, I know the get out clause is "we are going to plant some trees". But sooner or later you run out of space to do that. 

 

 

 

 

[Reorte]

52 minutes ago, Dave John said:

Would that also have to compensate for all the historic embedded energy if existing infrastructure is used ?

 

That'll be a big advantage to old infrastructure then. Whilst large scale steel production has never been carbon-neutral the majority of the power in the actual building was muscle power.

[Nearholmer]

SM

 

I’ve already accidentally wandered this thread off into the history of railway electrification probably too far, but it might be worth highlighting that the three-phase supplied mountain railways constitute something of a special case.

 

Before power electronics, controlling the speed of three-phase motors to any fine degree was difficult and complicated (the circuit diagrams of big c1900 three phase locos make your head ache) so although it was done (and lasted longest in main line service in Italy) it only ‘stuck’ as a system on a few railways where speed didn’t need to be finely controlled, just very consistent.

 

We got within a millimetre of having such a line in Britain, in the form of what became the Welsh Highland, and some of the locos were built for it, but it went through one of its many bankruptcies. IIRC that was to be hydroelectric, and the dam for it burst causing loss of life.

 

Also going from memory, I think the Gothard Railway was initially three phase, but converted to single phase late based on Simplon Railway experience.

 

Three phase railways, using three phase motors, could use industrial frequency way before single phase railways could, but not all did, and industrial frequency hadn’t been standardised then anyway.

 

K

[AMJ]

I have not heard of silent electric locomotives even our models are quite noisy.

 

DB & OBB both have a few electrics that the locals have given them a name after one of the music conductors as they make distinctive notes as they accelerate away from rest at stations.

[Reorte]

Any train moving at speed will be pretty noisy just from the wheel-rail interface, even on plain continually welded track, and perhaps aerodynamic noise too. Rubber would reduce but not eliminate that and as has already been pointed out be lousy for efficiency (presumably less of an issue on the lower-speed metro systems where it is used).

Edited February 3, 2020 by Reorte

[Nearholmer]

The man is quoted as saying ‘quiet’ and electric motive power can certainly be that, although can and always is are not the same thing.

 

Soft (Rubber tyre) wheels are inefficient by comparison with steel on steel wherever they are used, which is (a) part of why so few metros adopt the system,  and (b) modern practice, especially on HGVs and EVs is to use ‘rock-hard’ tyres.

 

You can get a rough(!) feel for the hard-on-hard vs soft-on-soft energy efficiency difference pumping up the tyres of a bike and riding it on a smooth road, then letting them down a tiny bit to ride on firm, mown grass ...... legs are great indicators of losses in the system!

Edited February 3, 2020 by Nearholmer

[PatB]

What's wrong with the sound of a brace of Paxman Valentas at full chat, I ask?

[Reorte]

5 hours ago, Lantavian said:

This might well be an issue for preserved railways. Steam locos produce a lot of CO2. 

 

They're also numerically insignificant, so much less than diesel trains on the national network, and I'd be surprised if they're significant in the overall grand scheme of things.

[Nick C]

In terms of the carbon-neutrality side, there is now a small solar farm connected directly to the Network Rail substation at Aldershot, and providing a small amount of traction current (https://www.independent.co.uk/travel/news-and-advice/solar-power-trains-railway-aldershot-uk-world-first-a9076136.html)

 

According to one of the people involved, even though that's only a small proof-of-concept system, they've done the numbers and reckon they could provide around 20% of the traction power from directly connected solar.

[PatB]

On 04/02/2020 at 19:15, Reorte said:

 

They're also numerically insignificant, so much less than diesel trains on the national network, and I'd be surprised if they're significant in the overall grand scheme of things.

True, but they are also a rather visible target, clearly give pleasure to people (always a black mark in some eyes) and also, being numerically insignificant, are ripe to become collateral damage from legislation aimed at something else. It would pay not to become complacent, as legislators have a long history of going after visible but insignificant minorities, rather than the beige majorities who are the actual culprits.