Is rail electrification the future, or the past

[whole diary]

[simonw]

I recently heard Chris Grayling questioning the need for electrification for Cardiff-Swansea and London Midland line. Whilst initially fuming, firmly believing we should electrify the whole network over 20-30 years, he then commented on new technologies including battery trains and hydrogen power.

At this point, my firm belief in electrification evaporated, why should we spend billions of pounds when stopping services can be powered by battery, and log distance services can powered by hydrogen? Both offer clean power, electrical tractiona n and performance.

Is C Grayling, and obviously his DfT^» (Department for Transport - about) team, right? or should we still be installing overhead power system, upgrading tunnels, etc?

[ChrisB]

If they delay much longer, other alternatives will be developed, there's no doubt.

There is doubt as to whether the UK^▸ (United Kingdom)'s electricity generation could actually cope if all lines were electrified quickly anyway. Whichever, doing nothing except bi-mode will only work for one stock rotation, and so he's just kicking the decision into the long grass, similar to what they've done/doing with airport capacity....

[ellendune]

To my mind there needs to be a long term (initially undated) plan  of which lines are priorities for with authorisation to NR^» (Network Rail - home page) to fund the basic planning of the work on each line. This would be followed by detailed planning of other works that will be required on these lines so that this can be carried out in advance, or passive provision made in the electrification.  So the whole work would be planned at least up to GRIP^▸ (Guide to Railway Investment Projects) 4 (single option development). 

The plan would then be prioritised and the early stages at least would be programmed. 

Advance works to provide the clearances required and any signalling works would then be authorised in a phased programme (so the whole area is not disrupted at once by the inevitable road closures) before actual electrification work started. 

I assume all new overbridges provide electrification clearances?  Equally all new signalling work should assume electrification. 

[Red Squirrel]

Hydrogen should be considered as a way of storing energy, not as a fuel. There are no hydrogen wells.

Making hydrogen is a good way of soaking up surplus energy (for example that which is generated by wind turbines when there is no other demand for it) but hydrogen fuel cells are not particularly efficient - they convert about 20% of the stored energy into power, which is about the same as internal combustion engines.

Long-distance rail systems are very well suited to receiving their power efficiently via OHLE. Branch lines may be suited to battery power (which is 80% efficient). Hydrogen will without doubt play a part in a future energy distribution and storage system, but its use in transport systems is likely to be limited.

And Grayling? He's just looking for excuses for not spending the money.

[simonw]

If I was looking for a way to store excess green power (overnight wind turbine, etc) it would not be Hydrogen storage, but methane.

CO2 + H2O => CH4 + 02

As a bonus, we already have large storage systems for methane, so it would be very easy to do.

[broadgage]

IMO^▸ (in my opinion), rail electrification is still the future, despite network rails inability to deliver it within budget or on time.
I do not expect hydrogen to be used on a significant scale, for the reasons given by others.
Diesel fuel is acceptable in the short term but will fall out of favour as supplies deplete and concerns over pollution grow.

That leaves electric power, from overhead equipment as the only likely technology for fast long distance trains.
Battery technology has improved substantially and may well be used for branch lines, especially in scenic areas where OHLE is objected to.
I doubt that we will see battery trains travelling hundreds of miles at high speeds, remember that significant power is needed for internal heating and cooling as well as for traction.
Battery power may well be used for short sections of otherwise electrified main lines where erecting OHLE is problematic. The sea wall route at Dawlish comes to mind, as do tunnels and bridges with limited clearances.

Steam may have a limited part to play, but I can not foresee any general or large scale return to steam.

The future is electric, despite recent setbacks.

[Red Squirrel]

If I was looking for a way to store excess green power (overnight wind turbine, etc) it would not be Hydrogen storage, but methane.

CO2 + H2O => CH4 + 02

As a bonus, we already have large storage systems for methane, so it would be very easy to do.

The trouble is at the other end, when you reverse that equation and produce our old friend CO₂. Producing hydrogen from wind power by splitting water is carbon neutral.

[ellendune]

The trouble is at the other end, when you reverse that equation and produce our old friend CO₂. Producing hydrogen from wind power by splitting water is carbon neutral.

But if you do both ends then it is CO2 Neutral.  The bigger problem is if you get a leak Methane is 23 time more powerful a greenhouse gas than CO2

[Red Squirrel]

The trouble is at the other end, when you reverse that equation and produce our old friend CO₂. Producing hydrogen from wind power by splitting water is carbon neutral.

But if you do both ends then it is CO2 Neutral.  The bigger problem is if you get a leak Methane is 23 time more powerful a greenhouse gas than CO2

Good point. D'oh.

[bradshaw]

Currently most of the hydrogen is produced by reforming methane, thus releasing CO2 and aging to greenhouse gases. While the fuel cell has potential for it to be realised a better, greener way of sourcing hydrogen has to be developed.

The use of battery/electric bimodes, as trialled a few years ago, has more potential in the immediate future and would allow through services on short branches, like Windemere

The current vogue of the electro-diesel bimode, pioneered on the Southern Region in the 60s, does allow for the development of a rolling, affordable electrification programme. Provided common sense prevails on the safe distance needed for 25kV clearances and the adoption of the new NR^» (Network Rail - home page) standards for OHLE structures.

[Bmblbzzz]

Battery power is a form of electrification, so if it is capable of appropriate speeds and distances for a particular line, I'd consider it perfectly acceptable. Battery technology is continually developing so there's hope in that direction yet. Nevertheless, for the foreseeable future, OHL^▸ (Over-Head Line) is far superior on power and distance.

It's clear that diesel remains the power source of the present, in the same way that coal was the power source of the present in the 1960s.

[JayMac]

Stick with the electricity. With more new build nuclear, and increased wind/solar, to generate it.

[Red Squirrel]

Currently most of the hydrogen is produced by reforming methane

I'll forgive your current pun, given the context; yes most hydrogen is produced from steam reforming of, as you say, methane. But these are exciting times.

[TonyK]

If I was looking for a way to store excess green power (overnight wind turbine, etc) it would not be Hydrogen storage, but methane.

CO2 + H2O => CH4 + 02

As a bonus, we already have large storage systems for methane, so it would be very easy to do.

All that is missing is the very large amount of energy needed to reverse the reaction that provided the CO₂ and H₂O in the first place. No such thing as a free lunch.

[SandTEngineer]

...as it happens: http://www.railwaygazette.com/news/traction-rolling-stock/single-view/view/hydrogen-fuel-cell-multiple-units-ordered.html

...and this from the Railway Gazette of 2008

Energy choice

The level of traffic is a key factor when comparing the cost of electrifying an existing railway with the cost of alternatives.

One can calculate or estimate the number of vehicle-km per kilometre of electrified track. Along with the electrification costs per track-km this number can be used to calculate the average costs per vehicle-km. This resulting number should be the critical factor in deciding between conventional electrification and the adoption of alternative traction.

Converting a railway for hydrogen trains will not require major investment in infrastructure, only in new rolling stock and the fuel supply. At present a hydrogen train would be considerably more expensive than its diesel powered equivalent, but this is certain to change over the next 10 to 15 years.

A recent study undertaken by the UK^▸ (United Kingdom)'s Rail Safety & Standards Board estimated that if the general cost targets for fuel cell technology are reached by 2020, a hydrogen train would be only 5% to 15% more expensive than an ordinary DMU^▸ (Diesel Multiple Unit), and hydrogen power will be more cost effective than electrification on railways with low to medium traffic densities.

But the application of general cost estimates to specific applications such as trains is not entirely without problems.

Energy efficiency

With diesel traction, only around a third of the energy in the fuel is converted to kinetic energy. With electric traction, almost 90% of the energy from the grid can be transferred to the wheels. Of course the losses in the power station and during transmission need to be added, and when the electricity is produced by fossil fuels the overall efficiency 'from well to wheel' is not quite so impressive. But if the electricity comes from renewable sources the overall efficiency remains high.

Hydrogen fuel cells have a lower energy efficiency then conventional electrification, due to the conversion losses in hydrogen production (electrolysis has an 80% efficiency), hydrogen storage (90%), the fuel cell (45%) and electric motor (90%). But hydrogen fuel produced using renewable energy will still have an overall energy efficiency comparable to diesel traction at roughly 30%, and that is before we take into account the considerable gains that can be achieved through the use of regenerative braking.

Hydrogen for railway use can be produced by electrolysis of water, with the environmental benefits dependent on the method of electricity generation, which can include renewable sources such as wind turbines. Surplus industrial hydrogen is a shorter-term source of fuel, and both options are currently available at the project site.