What are the advantages of hydrogen trains, compared to overhead electrified trains?

[greywagtail]

I'm new to this forum and trains generally so please understand if I've written this in the wrong place/format, or if I don't know technical terms.
I'm curious about the reasons behind the development of hydrogen trains. I know they're marketed as better for the environment, but there's some problems with that to the point I don't really understand how they're better than overhead electrified trains like we have now.

Hydrogen trains are advertised as better for the environment than electric because the trains' only emissions are steam. But the energy needed to electrolyse that hydrogen mostly comes from natural gas, which is still a fossil fuel, the same as electrified trains if their electricity comes from fossil fuels. Wouldn't it make more sense to work towards powering trains with renewable energy, instead of making trains that use non-renewable energy in a different way?

I've also read that hydrogen trains would have lithium batteries to store the energy produced on the train. Lithium mining certainly isn't sustainable. That ties into the two positive things I know about hydrogen trains, which is that they could be used on tracks that don't have enough traffic to justify electrifying, and can be used even if overhead lines fail.

Using hydrogen trains on non-electrified routes makes sense, because it's probably better than diesel. But I don't understand how that makes hydrogen trains "the future of the rail industry" as I've seen in some articles. There is certainly an issue with "carbon neutral" things ignoring the emissions a step removed from the product, like electric cars with lithium batteries running off electricity that could be made with fossil fuels. So maybe it's a case ignoring the issues because the product just sounds greener. Or maybe it's a case of new and impressive things being built because they're new and impressive.

I'm curious what other people think about it! [:

 

[andrew749]

Electric trains have zero emissions - the emissions happen at the power station instead.

 

[AM9]

Electric trains have zero emissions - the emissions, if any, happen at the power station instead.

Corrected that for you. in the future an increasingly large proportion of electricity used by trains will be from renewable sources. It's possible that hydrogen fueled trains might use green hydrogen, but given the inefficiency of that process and the lack of assurance that projects being touted as 'green' will use hydrogen being sourced that way.

 

[Trainbike46]

I'm new to this forum and trains generally so please understand if I've written this in the wrong place/format, or if I don't know technical terms.
I'm curious about the reasons behind the development of hydrogen trains. I know they're marketed as better for the environment, but there's some problems with that to the point I don't really understand how they're better than overhead electrified trains like we have now.

Hydrogen trains are advertised as better for the environment than electric because the trains' only emissions are steam. But the energy needed to electrolyse that hydrogen mostly comes from natural gas, which is still a fossil fuel, the same as electrified trains if their electricity comes from fossil fuels. Wouldn't it make more sense to work towards powering trains with renewable energy, instead of making trains that use non-renewable energy in a different way?

If anyone is claiming that hydrogen trains are more environmentally friendly than electric trains they are lying; Hydrogen would be produced using electricity from the grid, and they require more energy overall, so they use more electricity than a full electric train. Clearly, the grid needs to be decarbonised ASAP, but as hydrogen trains require more electricity they are always less sustainable OHLE electric or even Battery electric trains.

I've also read that hydrogen trains would have lithium batteries to store the energy produced on the train. Lithium mining certainly isn't sustainable. That ties into the two positive things I know about hydrogen trains, which is that they could be used on tracks that don't have enough traffic to justify electrifying, and can be used even if overhead lines fail.

Using hydrogen trains on non-electrified routes makes sense, because it's probably better than diesel. But I don't understand how that makes hydrogen trains "the future of the rail industry" as I've seen in some articles. There is certainly an issue with "carbon neutral" things ignoring the emissions a step removed from the product, like electric cars with lithium batteries running off electricity that could be made with fossil fuels. So maybe it's a case ignoring the issues because the product just sounds greener. Or maybe it's a case of new and impressive things being built because they're new and impressive.

I'm curious what other people think about it! [:

Hydrogen is almost certainly not the future of the rail industry, because they are more expensive,require more energy and are less sustainable than electric trains; they may play a role on routes that have very low traffic and are too long to be practical for use of battery EMUs. In the UK that basically limits them to the West Highland, Far North and Kyle of Lochalsh lines. Other routes would be way better off with either OHLE or BEMUs.

Not a train example, but my local bus operator (translink NI) has both battery electric buses and hydrogen buses. In a presentation of decarbonising NIs public transport they stated that the hydrogen buses are:
- More expensive to buy
- More expensive to maintain
- More expensive in energy
- Required more changes to the bus depot (as hydrogen is an explosive gas), which further raised cost
compared to battery electric buses. The only reason they did get some hydrogen was because they had one route where the battery buses couldn't provide an all day service without recharging the battery. These same issues will apply in the consideration when choosing between OHLE, Battery and Hydrogen trains

I hope that makes sense! Welcome to the forum by the way!

 

[AM9]

If anyone is claiming that hydrogen trains are more environmentally friendly than electric trains they are lying; Hydrogen would be produced using electricity from the grid, and they require more energy overall, so they use more electricity than a full electric train. Clearly, the grid needs to be decarbonised ASAP, but as hydrogen trains require more electricity they are always less sustainable OHLE electric or even Battery electric trains.

Hydrogen is almost certainly not the future of the rail industry, because they are more expensive,require more energy and are less sustainable than electric trains; they may play a role on routes that have very low traffic and are too long to be practical for use of battery EMUs. In the UK that basically limits them to the West Highland, Far North and Kyle of Lochalsh lines. Other routes would be way better off with either OHLE or BEMUs.

Not a train example, but my local bus operator (translink NI) has both battery electric buses and hydrogen buses. In a presentation of decarbonising NIs public transport they stated that the hydrogen buses are:
- More expensive to buy
- More expensive to maintain
- More expensive in energy
- Required more changes to the bus depot (as hydrogen is an explosive gas), which further raised cost
compared to battery electric buses. The only reason they did get some hydrogen was because they had one route where the battery buses couldn't provide an all day service without recharging the battery. These same issues will apply in the consideration when choosing between OHLE, Battery and Hydrogen trains

I hope that makes sense! Welcome to the forum by the way!

There's a lot of talk about synthetic fuel for aviation use. Maybe that might be a better solution for 'long thin' rail routes than pure hydrogen.

 

[Trainbike46]

There's a lot of talk about synthetic fuel for aviation use. Maybe that might be a better solution for 'long thin' rail routes than pure hydrogen.

Maybe, I guess we'll have to see. Then again, those are usually manufactured out of hydrogen, and doing that and using them in an internal combustion engine instead of a fuel cell (like hydrogen) would reduce efficiency even more, and therefore require even more fuel.

As I've stated before, the priority for decarbonisation shouldn't be on the long, thin routes anyway. It should be on routes like the snow hill lines, the chiltern lines, the remainder of the GWML, and other busy lines. For the long thin routes we can wait and see for now (though scotrail has already decided what it will do with the West Highland, Far North and Kyle lines!)

 

[tbtc]

Welcome to the Forum

Blunt answer is that i don’t think that hydrogen trains have any advantages over electric ones

BUT our enlightened DfT don’t seem in much of a hurry to electrify more lines any time - it’s around a decade since Network Rail’s “control period” (the five year plan/ commitments sometimes referred to as CP5) promised electrification from London to Bristol / Oxford/ Nottingham/ Sheffield etc (as well as various other projects like the complete TransPennine electrification and the “electric spine” from the Midlands to Southampton , to get freight converted to electric) but clearly that’s not happened/ happening

As a result, we are stuck with a backlog of potential electrification projects (whereas, if the CP5 promises had been delivered, we’d probably be onto filling in the gaps between electrified lines by now, e.g. once you’ve done the MML as far as Sheffield then it’s not much further to go to Moorthorpe/ Doncaster, once you’ve wired main lines then secondary routes become a lot easier to justify)

I’ve given up hope of much electrification over the next decade, even Scottish plans are more focused on “wire the easy bits and let bi-mode trains deal with the awkward tunnels/ bridges”

Ten years ago, the CP5 plans fitted nicely into the availability of midlife EMUs freed up by Thameslink/ Crossrail (315/ 317/ 319 etc) which we could squeeze a decade out of before needing to replace them (in the way that BR kept electrification costs down by putting cascaded 305/ 308s etc on routes like Ilkley/ North Berwick, so that you didn’t have to factor in the cost of brand new trains when assessing electrification projects)

That would then mean we’d have enough cascaded EMUs to replace all Pacers and start making dents into the oldest Sprinters in the fleet

However, it obviously hasn’t worked like that, and the new public sector model of Government/ GBR/ DfT doesn’t look like they’ll be particularly generous over the next few years

So how do we deal with the perception that trains are dirty/ smelly/ polluting? Look at Marylebone, where the 68s chugging away stand out in a neighbourhood used to “zero emission” buses/taxis/ private cars (due to the congestion charge and lots of investment in buses by TfL)

We enthusiasts have played the “trains are Green, we should have more trains because it’s good for the environment” card, but as many big cities introduce Clean Air zones etc, the stench of diesel trains becomes more noticeable - I don’t think that New Street is any worse today than it’s ever been but there smell is much more noticeable these days because other polluters have cleaned up their act somewhat

So, in the absence of electrification any time soon, a train producing zero emissions at source becomes a lot more appealing - if electrification was being delivered as hoped for then we wouldn’t be considering compromised alternatives like hydrogen but i think That there’s a real danger that heavy rain will look like “part of the problem” rather than “part of the solution” if people are still stood breathing significant amounts of diesel fumes at busy stations, so I’m reluctantly in favour of hydrogen (or “bionic duckweed” or whatever else is flavour of the month) because I don’t think we can keep on burning all of these fossil fuels in city centres and get away with it

 

[Wolfie]

Welcome to the Forum

Blunt answer is that i don’t think that hydrogen trains have any advantages over electric ones

BUT our enlightened DfT don’t seem in much of a hurry to electrify more lines any time - it’s around a decade since Network Rail’s “control period” (the five year plan/ commitments sometimes referred to as CP5) promised electrification from London to Bristol / Oxford/ Nottingham/ Sheffield etc (as well as various other projects like the complete TransPennine electrification and the “electric spine” from the Midlands to Southampton , to get freight converted to electric) but clearly that’s not happened/ happening

As a result, we are stuck with a backlog of potential electrification projects (whereas, if the CP5 promises had been delivered, we’d probably be onto filling in the gaps between electrified lines by now, e.g. once you’ve done the MML as far as Sheffield then it’s not much further to go to Moorthorpe/ Doncaster, once you’ve wired main lines then secondary routes become a lot easier to justify)

I’ve given up hope of much electrification over the next decade, even Scottish plans are more focused on “wire the easy bits and let bi-mode trains deal with the awkward tunnels/ bridges”

Ten years ago, the CP5 plans fitted nicely into the availability of midlife EMUs freed up by Thameslink/ Crossrail (315/ 317/ 319 etc) which we could squeeze a decade out of before needing to replace them (in the way that BR kept electrification costs down by putting cascaded 305/ 308s etc on routes like Ilkley/ North Berwick, so that you didn’t have to factor in the cost of brand new trains when assessing electrification projects)

That would then mean we’d have enough cascaded EMUs to replace all Pacers and start making dents into the oldest Sprinters in the fleet

However, it obviously hasn’t worked like that, and the new public sector model of Government/ GBR/ DfT doesn’t look like they’ll be particularly generous over the next few years

So how do we deal with the perception that trains are dirty/ smelly/ polluting? Look at Marylebone, where the 68s chugging away stand out in a neighbourhood used to “zero emission” buses/taxis/ private cars (due to the congestion charge and lots of investment in buses by TfL)

We enthusiasts have played the “trains are Green, we should have more trains because it’s good for the environment” card, but as many big cities introduce Clean Air zones etc, the stench of diesel trains becomes more noticeable - I don’t think that New Street is any worse today than it’s ever been but there smell is much more noticeable these days because other polluters have cleaned up their act somewhat

So, in the absence of electrification any time soon, a train producing zero emissions at source becomes a lot more appealing - if electrification was being delivered as hoped for then we wouldn’t be considering compromised alternatives like hydrogen but i think That there’s a real danger that heavy rain will look like “part of the problem” rather than “part of the solution” if people are still stood breathing significant amounts of diesel fumes at busy stations, so I’m reluctantly in favour of hydrogen (or “bionic duckweed” or whatever else is flavour of the month) because I don’t think we can keep on burning all of these fossil fuels in city centres and get away with it

An excellent post. Hydrogen is at best a half-assed solution in the absence of proper electrification.

 

[SynthD]

Green hydrogen and conflict-free batteries are necessary for the full ideal of hydrogen powered vehicles to be delivered. It’s hard to say we will never reach that.

 

[E27007]

Do you recall the prediction of the 1950s, in the future, the motor car with a nuclear reactor under the bonnet?
I had a two-hour conversation with an Engineer responsible for commissioning hydrogen fuel cells, it was not good news for the temperamental hydrogen fuel cell, so many issues, failure to initiate, backfiring, water-logging , contamination of the hyrdogen - air interface.
I left with the thought, the latest version of the nuclear car story from all those years ago

 

[GRALISTAIR]

Welcome to the Forum

Blunt answer is that i don’t think that hydrogen trains have any advantages over electric ones

+1 from me

I'm new to this forum and trains generally so please understand ---

Welcome

 

[greywagtail]

Thank you all very much [: I'm not going to reply to everyone's messages because I don't want to spam, but I appreciate hearing everyone's thoughts. It's very interesting.

Green hydrogen and conflict-free batteries are necessary for the full ideal of hydrogen powered vehicles to be delivered. It’s hard to say we will never reach that.

Thank you! That is true. That would improve the case for hydrogen trains. I appreciate what Trainbike47 says also about potential situations in which they could be useful.

-- In the UK that basically limits them to the West Highland, Far North and Kyle of Lochalsh lines. Other routes would be way better off with either OHLE or BEMUs.

Not a train example, but my local bus operator (translink NI) has both battery electric buses and hydrogen buses. In a presentation of decarbonising NIs public transport they stated that the hydrogen buses are:
- More expensive to buy
- More expensive to maintain
- More expensive in energy
- Required more changes to the bus depot (as hydrogen is an explosive gas), which further raised cost
compared to battery electric buses. The only reason they did get some hydrogen was because they had one route where the battery buses couldn't provide an all day service without recharging the battery. These same issues will apply in the consideration when choosing between OHLE, Battery and Hydrogen trains

Very interesting!

-- our enlightened DfT don’t seem in much of a hurry to electrify more lines any time - it’s around a decade since Network Rail’s “control period” (the five year plan/ commitments sometimes referred to as CP5) promised electrification from London to Bristol / Oxford/ Nottingham/ Sheffield etc (as well as various other projects like the complete TransPennine electrification and the “electric spine” from the Midlands to Southampton , to get freight converted to electric) but clearly that’s not happened/ happening

As a result, we are stuck with a backlog of potential electrification projects (whereas, if the CP5 promises had been delivered, we’d probably be onto filling in the gaps between electrified lines by now, e.g. once you’ve done the MML as far as Sheffield then it’s not much further to go to Moorthorpe/ Doncaster, once you’ve wired main lines then secondary routes become a lot easier to justify)

I’ve given up hope of much electrification over the next decade, even Scottish plans are more focused on “wire the easy bits and let bi-mode trains deal with the awkward tunnels/ bridges”

Ten years ago, the CP5 plans fitted nicely into the availability of midlife EMUs freed up by Thameslink/ Crossrail (315/ 317/ 319 etc) which we could squeeze a decade out of before needing to replace them (in the way that BR kept electrification costs down by putting cascaded 305/ 308s etc on routes like Ilkley/ North Berwick, so that you didn’t have to factor in the cost of brand new trains when assessing electrification projects)

That would then mean we’d have enough cascaded EMUs to replace all Pacers and start making dents into the oldest Sprinters in the fleet

However, it obviously hasn’t worked like that, and the new public sector model of Government/ GBR/ DfT doesn’t look like they’ll be particularly generous over the next few years

So how do we deal with the perception that trains are dirty/ smelly/ polluting? Look at Marylebone, where the 68s chugging away stand out in a neighbourhood used to “zero emission” buses/taxis/ private cars (due to the congestion charge and lots of investment in buses by TfL)

We enthusiasts have played the “trains are Green, we should have more trains because it’s good for the environment” card, but as many big cities introduce Clean Air zones etc, the stench of diesel trains becomes more noticeable - I don’t think that New Street is any worse today than it’s ever been but there smell is much more noticeable these days because other polluters have cleaned up their act somewhat

So, in the absence of electrification any time soon, a train producing zero emissions at source becomes a lot more appealing - if electrification was being delivered as hoped for then we wouldn’t be considering compromised alternatives like hydrogen but i think That there’s a real danger that heavy rain will look like “part of the problem” rather than “part of the solution” if people are still stood breathing significant amounts of diesel fumes at busy stations, so I’m reluctantly in favour of hydrogen (or “bionic duckweed” or whatever else is flavour of the month) because I don’t think we can keep on burning all of these fossil fuels in city centres and get away with it

Thank you for explaining CP5! That's a very good point. I think it is definitely a good idea for environmental planning to encourage public transport, esp. trains, rather than cars so I understand where you're coming from. It's a shame about the network's slow electrification.

Do you recall the prediction of the 1950s, in the future, the motor car with a nuclear reactor under the bonnet?
I had a two-hour conversation with an Engineer responsible for commissioning hydrogen fuel cells, it was not good news for the temperamental hydrogen fuel cell, so many issues, failure to initiate, backfiring, water-logging , contamination of the hyrdogen - air interface.
I left with the thought, the latest version of the nuclear car story from all those years ago

I guess they might be solved sometime. Or they might not. I guess it's a matter of time to see. I just hope it will be considered in the fringe cases Trainbike47 mentioned and not a chance to "innovate our way out of problems" when there's already existing solutions to them.

Thank you for the welcomes! [:

 

[Nottingham59]

I'm curious about the reasons behind the development of hydrogen trains. ...

I'm curious what other people think about it!

My view is that Hydrogen may have a place as a energy vector for rail traction, but it is difficult to be sure. The technologies of hydrogen fuel cells, water electrolysis, and traction batteries are evolving so quickly that nobody really knows whether batteries or hydrogen will eventually become the economic winner for non-electrified lines.

OVERHEAD LINE ELECTRIFICATION (OHLE)
The first thing to realise is that overhead electrification of the railways is insanely expensive. [EDIT: in the UK at least.] Electrifying the Great Western mainline cost between £2M and £2.5M per single track kilometre. The industry is trying to bring that cost down, and I don't know what the latest figures for the Midland Mainline (MML) are, but everything on the railway costs around five times as much as it should. And it's not just the engineering: planning, regulatory, and project accounting rules means that cutting these costs becomes almost impossible.

Which means that OHLE is not financially viable for routes carrying less than about 8tph in each direction, though they fudge the figures with "non-financial benefits" or "Wider Economic Impacts" to justify electrifying routes that carry around 4tph, like the MML.

So less-used routes will have to use some sort of stored energy solution, rather than continuous electrification.

BIODIESEL
The cheapest option for low-carbon transport is to use bio-diesel or Hydrogenated Vegetable Oil (HVO) as a diesel substitute that can simply be used by existing rolling stock. I don't know why this isn't manadated for the entire diesel fleet today. Probably because there are no reseach grants or subsidies available ..... and converting today would mean ToCs / HM Treasury paying more for HVO than for fossil-fuel diesel.

BATTERY TRAINS
Battery trains are already in regular passenger service in Europe. Trains like the Stadler Flirt Akku have a range off the wires of 150km and can recharge on the wires in 15mins (though those figures will apply to different models). See https://www.stadlerrail.com/en/flirt-akku/details/

That means for longer routes, like lines to Penzance or to Inverness, you would need to invest in OHLE at intervals along the route to recharge the trains on the go. Which would be expensive and faults could leave trains stranded.

I understand that batteries are around 90% efficient, i.e. for every 100 units of electrical energy you put in, you get 90 units out. So batteries could be competitive versus continuous electrification on many routes in Britain.

HYDROGEN
Cylinders of compressed hydrogen can store many times the energy of batteries. Alstom claim and range of 1000km for their H2 trains in passenger service. https://www.alstom.com/press-releas...radia-ilint-start-passenger-service-first-100
Which means you could serve Thurso or Penzance without any additional [lineside] infrastructure.

But I understand creating green hydrogen (through electrolysis of water), compressing it, and using it in a fuel cell is only about 60% efficient over the whole cycle. So hydrogen would be more expensive than batteries, wherever the cost of energy is the most important factor. Which is most of the time with the current electricity generating mix.

However, the reason why Greens get so excited about Hydrogen is that it works really well with a renewables electricity grid. At 1pm today, wind was generating 12GW, solar 6GW and the grid only needed 4GW of gas to meet overall demand. In 10 years time, when we have twice as many wind and solar farms, we would have had a surplus of renewables and the wholesale price of electricity would have been near zero. Hydrogen could soak up that surplus at low cost, which transforms its economics.

It's easy to store hydrogen for a week or two. All it needs are enough empty cylinders able to take 700 bar pressure. So you can generate hydrogen, at low cost, in the weeks when the wind is blowing and use it as needed. This makes the 60% efficiency figure irrelevant. Using batteries simply as a store of energy for weeks at a time would be much more expensive.

So Hydrogen may have a place in the future. The Scottish Government seems determined to order H2 trains for its rural lines, so we shall soon find out!

Personally, I think that batteries will win out, but I can't be sure. What I am sure about is that the industry should be doing is converting to HVO immediately; and ordering battery trains now to displace diesel trains on those many routes than could already support them (such as Paddington-Oxford etc. etc.) With a plan to cascade those battery trains on to other routes as OHLE gaps get filled in (e.g. Liverpool-Nottingham; EWR). But that would involve some sort of system-wide planning with a bit of common sense and a long-term view. Which the industry and the [UK] government have proved time and again are incapable of delivering.

 

[Bevan Price]

The main snag with hydrogen is that it needs to be stored in heavy cylinders, which adds unproductive weight to the train, which requires additional energy to move.

The other snag is that you need to be extremely careful to prevent hydrogen leaks, otherwise you create a potential risk of fire or explosions.

So yes, hydrogen fuel may have a place in rail traction - but electrification should be the preferred long-term option.

 

[tomuk]

OVERHEAD LINE ELECTRIFICATION (OHLE)
The first thing to realise is that overhead electrification of the railways is insanely expensive.

It isn't insanely expensive even if you do it the over the top Network Rail Great Western Electrification Programme way. The rest of Europe can do it for a much more reasonable cost per km.

We need to just get on and do it. Running diesels, even 40 year old 15x on the WHL or HOWL is fine for the time being. Their emissions are less than negligible.

 

[greywagtail]

My view is that Hydrogen may have a place as a energy vector for rail traction, but it is difficult to be sure. The technologies of hydrogen fuel cells, water electrolysis, and traction batteries are evolving so quickly that nobody really knows whether batteries or hydrogen will eventually become the economic winner for non-electrified lines.

OVERHEAD LINE ELECTRIFICATION (OHLE)
The first thing to realise is that overhead electrification of the railways is insanely expensive. Electrifying the Great Western mainline cost between £2M and £2.5M per single track kilometre. The industry is trying to bring that cost down, and I don't know what the latest figures for the Midland Mainline (MML) are, but everything on the railway costs around five times as much as it should. And it's not just the engineering: planning, regulatory, and project accounting rules means that cutting these costs becomes almost impossible.

Which means that OHLE is not financially viable for routes carrying less than about 8tph in each direction, though they fudge the figures with "non-financial benefits" or "Wider Economic Impacts" to justify electrifying routes that carry around 4tph, like the MML.

So less-used routes will have to use some sort of stored energy solution, rather than continuous electrification.

BIODIESEL
The cheapest option for low-carbon transport is to use bio-diesel or Hydrogenated Vegetable Oil (HVO) as a diesel substitute that can simply be used by existing rolling stock. I don't know why this isn't manadated for the entire diesel fleet today. Probably because there are no reseach grants or subsidies available ..... and converting today would mean ToCs / HM Treasury paying more for HVO than for fossil-fuel diesel.

BATTERY TRAINS
Battery trains are already in regular passenger service in Europe. Trains like the Stadler Flirt Akku have a range off the wires of 150km and can recharge on the wires in 15mins (though those figures will apply to different models). See https://www.stadlerrail.com/en/flirt-akku/details/

That means for longer routes, like lines to Penzance or to Inverness, you would need to invest in OHLE at intervals along the route to recharge the trains on the go. Which would be expensive and faults could leave trains stranded.

I understand that batteries are around 90% efficient, i.e. for every 100units of electrical energy you put in, you get 90 units out. So batteries could be competitive versus continuous electrification on many routes in Britain.

HYDROGEN
Cylinders of compressed hydrogen can store many times the energy of batteries. Alstom claim and range of 1000km for their H2 trains in passenger service. https://www.alstom.com/press-releas...radia-ilint-start-passenger-service-first-100
Which means you could serve Thurso or Penzance without any additional infrastructure.

But I understand creating green hydrogen (through electrolysis of water), compressing it, and using it in a fuel cell is only about 60% efficient over the whole cycle. So hydrogen would be more expensive than batteries, where the cost of energy is the most important factor. Which is most of the time with the current electricity generating mix.

However, the reason why Greens get so excited about Hydrogen is that it works really well with a renewables electricity grid. At 1pm today, wind was generating 12GW, solar 6GW and the grid only needed 4GW of gas to meet overall demand. In 10 years time, when we have twice as many wind and solar farms, we would have had a surplus of renewables and the wholesale price of electricity would have been near zero. Hydrogen could soak up that surplus at low cost, which transforms its economics.

It's easy to store hydrogen for a week or two. All it needs is enough empty cylinders able to take 700 bar pressure. So you can generate hydrogen, at low cost, in the weeks when the wind is blowing and use it as needed. This makes the 60% efficiency figure irrelevant. Using batteries simply as a store of energy for weeks at a time would be much more expensive.

So Hydrogen may have a place in the future. The Scottish Government seems determined to order H2 trains for its rural lines, so we shall soon find out!

Personally, I think that batteries will win out, but I can't be sure. What I am sure about is that the industry should be doing is converting to HVO immediately, and ordering battery trains now to displace diesel trains on those many routes than could already support them (such as Paddington-Oxford etc. etc.) With a plan to cascade those battery trains on to other routes as OHLE gaps get filled in (e.g. Liverpool-Nottingham; EWR). But that would involve some sort of system-wide planning with a bit of common sense and a long-term view. Which the industry and the government have proved time and again are incapable of delivering.

Thank you! Very very interesting to read. That's changed my thoughts about them. Definitely when using renewable electricity. I appreciate the links about European hydrogen trains.

 

[Nottingham59]

Thank you! Very very interesting to read. That's changed my thoughts about them. Definitely when using renewable electricity. I appreciate the links about European hydrogen trains.

You're welcome!

The rest of Europe can do it for a much more reasonable cost per km.

So they say. I will edit my rant accordingly.

 

[Trainbike46]

So they say. I will edit my rant accordingly.

Are you implying other countries are lying about their electrification costs?

It's easy to store hydrogen for a week or two. All it needs are enough empty cylinders able to take 700 bar pressure. So you can generate hydrogen, at low cost, in the weeks when the wind is blowing and use it as needed. This makes the 60% efficiency figure irrelevant. Using batteries simply as a store of energy for weeks at a time would be much more expensive.

I'm pretty sre it's not possible to achieve that 60% in practice

It's also important to consider the cost of the rolling stock; both purchase cost and maintenance cost. For those, OHLE is by far the cheapest on a per seat basis, as battery and hydrogen trains are effectively EMUs with extra bits added on, which add costs and potentially reduce seating capacity.

There's also the issue of freight traffic. Currently there is no technology other than OHLE to decarbonise rail freight.

By no means am I saying they're never the option, but the vast majority of lines should get OHLE ASAP. We just need to get on with it, like Scotland is doing

 

[Nottingham59]

Are you implying other countries are lying about their electrification costs?

No, I did not mean to give that impression at all; my points were directed at the UK. See for instance the RIA "Electfication Cost Challenge" report:

https://www.nsar.co.uk/wp-content/uploads/2019/03/RIAECC.pdf

It's also important to consider the cost of the rolling stock; both purchase cost and maintenance cost.

Of course. But the Benefits-Cost Ratio (BCR) calculations for electrification projects do include such reduced ongoing costs, over a 60-year investment horizon. If the reduced costs for rolling stock procurement and maintenance did actually cover the cost of OHLE electrification, then the BCR would be calculated as infinite. And I've not seen that for any recent UK electrification projects.

As far as I can tell, the crossover point where the ongoing savings actally pay for the electficiation is about 8tph day-time frequency.

(As an aside, can anyone point me to the BCR figures for current MML electrification schemes?)

There's also the issue of freight traffic. Currently there is no technology other than OHLE to decarbonise rail freight.

Sure. Freight is important on some lines, and could contribute to the investment case. But full electrification should be compared to freight using Class 93 tri-mode and Class 99 bi-mode locomotives, using OHLE when under the wires and HVO diesel equivalent off the wires. Which would fully decarbonise UK freight operations at a fraction of the cost of electrifying all freight lines. Thouhg there are many lines, like Felixstowe to Nuneaton, which should probably get electrified once bimode freight locomotives are available.

the vast majority of lines should get OHLE ASAP.

I'd vote for battery trains with discontinuous OHLE, supplemented by megawatt-capable plug-in chargers at termini. Cheaper and much faster to implement than full OHLE. But that's just my opinion.

We just need to get on with it, like Scotland is doing

Scotland at doing a lot of things right, particularly with a steady rate of OHLE projects, but much of their programme is based around discontinuous electrification, at least for the next ten years. Which is sort of my point. They just need to order a fleet of battery trains and get on with it.

 

[XAM2175]

They just need to order a fleet of battery trains and get on with it.

Which is what's happening:

ScotRail’s New Trains Procurement Programme

An advert for a tender for legal services for the above (https://www.publiccontractsscotland.gov.uk/search/show/search_view.aspx?ID=AUG455691) gives some more detail on the fleet plan ScotRail Trains (SRT) plans to replace 65% of its train fleet (around 675 carriages) in the period 2027 to...

railforums.co.uk

 

[Energy]

I'd vote for battery trains with discontinuous OHLE, supplemented by megawatt-capable plug-in chargers at termini. Cheaper and much faster to implement than full OHLE. But that's just my opinion.

Problem with discontinuous is that you either need a long distance to lower the pantograph or be going low speed or just change mode at a station. The power changeover near Didcot I think was ~4km before the electrification end since it can't be done at busy junctions where the driver is concentrating on something else.

 

[Nottingham59]

you either need a long distance to lower the pantograph or be going low speed or just change mode at a station.

Sure, that's understood. But the savings from not having to rebuild a load of bridges or dig out tunnels could be substantial, and there are plenty of lines where stations would make suitable places to change mode. I guess we'll just have to see how it goes in Scotland in a couple of years time.

 

[Class 317]

I'd be surprised if hydrogen has a future for trains.It's so inefficient as an energy storage medium.
Creating it by electrolysis is limited to around 35% efficiency due to the chemistry involved so green hydrogen loses 65% of green energy unavoidably.
Currently it's around 50% efficient converting hydrogen back to electricity in fuel cells. Fuel cell efficiency has not really improved since Ballard worked on them in the late 90's and early 00's where it went from 35% to 50%.

Overall conversion efficiency (energy in versus useful energy out) is around 25%.

Currently batteries have overall conversion efficiencies of 75% and upwards depending on climate's (cold and hot can reduce their efficiency) and applications.

Battery tech has been improving at a rate of 7% a year with quite a few companies working on new types of battery technology including solid state batteries which are likely to increase energy density and reduce costs at a faster rate in the future.

A battery train with a 150- 200 mile range should be possible now with current battery technology if designed as a battery train from scratch. With fast charging at stops this could be extended to 2 to 3 time's this range. This should work for most branch lines and rural routes.

I think discontinuous electrification is the way to go for routes like Ashford to Hastings. A trickle charge whilst on electrified sections to provide range for branches with direct through services etc.

As battery tech improves discontinuous electrification and pure battery electric trains should be viable over a greater range of routes.

In terms of charging infrastructure, most rapid charging stations for cars are now using systems where batteries are trickle charged over time and then fast charge the car. Similar chargers would work for rural lines.

 

[Monarch010]

Problem with discontinuous is that you either need a long distance to lower the pantograph or be going low speed or just change mode at a station. The power changeover near Didcot I think was ~4km before the electrification end since it can't be done at busy junctions where the driver is concentrating on something else.

New trains are endowed with advanced technology, could not the changeover be automated?

 

[Energy]

New trains are endowed with advanced technology, could not the changeover be automated?

It is, see the 800s. It still requires the drivers attention to ensure the pantograph is lowered etc. and therefore can't be done at busy junctions.

Sure, that's understood. But the savings from not having to rebuild a load of bridges or dig out tunnels could be substantial, and there are plenty of lines where stations would make suitable places to change mode. I guess we'll just have to see how it goes in Scotland in a couple of years time.

Depends on the definition of discontinuous electrification.

Say there was 3 sections of a train journey, A B and C. If B was a bit tricky to electrify then you could just do A and C and have it switch to batteries at a station. This would be possible.

Having the pantograph drop before every bridge and tunnel would be much more difficult and would likely leave with not a lot electrified anyway due to the need to give adequate time for the driver and the automatic power switchover.

I'm not sure what the Scottish and Welsh governments mean by discontinuous, but I'd expect it it to be more like electrification at either end and battery in the middle.

 

[Snow1964]

Depends on the definition of discontinuous electrification.

Say there was 3 sections of a train journey, A B and C. If B was a bit tricky to electrify then you could just do A and C and have it switch to batteries at a station. This would be possible.

Having the pantograph drop before every bridge and tunnel would be much more difficult and would likely leave with not a lot electrified anyway due to the need to give adequate time for the driver and the automatic power switchover.

I'm not sure what the Scottish and Welsh governments mean by discontinuous, but I'd expect it it to be more like electrification at either end and battery in the middle.

There are basically two forms of discontinuous (short dead sections where live wire is replaced by an insulated section, usually under complicated low bridges); and long sections where batteries need to be used, and pantographs need to be dropped as no wires.

Clearance problems are not as bad nowadays as it is possible to fit solid bar conductors (which are relatively slim vertically) and there are insulated coatings that can be painted on metal over bridges.

 

[Nottingham59]

I'm not sure what the Scottish and Welsh governments mean by discontinuous, but I'd expect it it to be more like electrification at either end and battery in the middle.

That's what I mean in this context. Maybe a better term would be "intermittent electrification"?

To illustrate this, think about when the MML is electrified to Nottingham and Sheffield. This would immediately allow the following routes to convert to BEMU trains with, say, 50 miles of range:

• Liverpool-Nottingham, recharging at Liverpool-Hunt's Cross; Deansgate-Hazel Grove; Dore-Sheffield-Clay Cross; Nottingham Station.
• Newark Castle - Matlock
• Nottingham - Crewe
• Birmingham - Stansted

With 100 mile range, you could do Nottingham-Cardiff; Nottingham-Worksop; Nottingham-Norwich. So the entire passenger network from Nottingham, except the Lincolnshire routes, all without having to install a single extra mile of OHLE. And no need for Hydrogen either.

But I don't see any mention of these possibilities coming out of DfT, or GBR or the ToCs.

 

[snowball]

I'm not sure what the Scottish and Welsh governments mean by discontinuous, but I'd expect it it to be more like electrification at either end and battery in the middle.

Scottish (Decarbonisation Action Plan) and Welsh (Core Valley Lines) are quite different as far as I can see, on the basis of the information available so far. In Scotland we may have to wait several years to see how things develop, unless more information becomes available, for example next spring when the first review of the policy is due.

In the Core Valley Lines the whole idea is short earthed stretches of overhead line to avoid the expense of reconstructing difficult bridges or tunnels. I assume these would trigger circuit breakers on the train as existing neutral sections do, but with the pan remaining up. Perhaps someone will correct me on this.

The Core Valley Lines will also include some longer unelectrified stretches (such as the Rhymney line?) where the pantograph will need to be down - probably this will require driver action?

In Scotland the word mostly used is partial, not discontinuous. There is no evidence yet of firm proposals for short electrified or unelectrified sections. The shortest ones we know of yet are several miles, with, for example, electrified stretches radiating in four directions from a feeder station to be installed at the junction at Thornton, Fife. Some routes will be decarbonised by partial electrification and the use of battery trains. The intention seems to be that partial electrification will be compatible with the possibility of future conversion to full electrification. There are differing views in this forum as to how often this later infill will actually happen.

In Scotland the main motive for partial electrification is to decarbonise the network faster than would happen if they concentrated on complete electrification of one route at a time.

 

[Mikey C]

I don't think anyone is suggesting that hydrogen is BETTER than overhead electrification.

It's much cheaper and quicker though, and thus attractive for lightly used lines which will be well down the pecking order for electrification, even with a rolling programme, it will take a long time to get to the quiet branch lines. For certain lines near sources of hydrogen, it may be an alternative alternative to battery power.

 

[tomuk]

It's much cheaper and quicker though,

Than retaining some scant diesels for the infrequent WHL or some otherwise standard EMUs fitted with batteries?