Will Zero-Carbon Freight Trains Be Powered By Battery, Electric Or Hydrogen Locomotives?
These are a few initial thoughts.
We Will Not Have A One-Size-Fits-All Solution
If you consider the various freight and other duties, where diesel locomotives are used, you get a long list.
- Light freight, where perhaps a Class 66 locomotive moves a few wagons full of stone to support track maintenance.
- Intermodal freight, where a Class 66 locomotive moves a long train of containers across the country.
- Stone trains, where a Class 59 or Class 70 locomotive moves a very heavy train of aggregate across the country.
- Empty stock movements, where a diesel locomotive moves an electrical multiple unit.
- Supporting Network Rail with trains like the New Measurement Train, which is hauled by two diesel Class 43 power cars.
- Passenger trains at up to and over 100 mph.
I can see a need for several types of zero-carbon locomotive.
- A light freight locomotive.
- A medium freight locomotive, that is capable of hauling many intermodal trains across the country and would also be capable of hauling passenger services.
- A heavy freight locomotive, capable of hauling the heaviest freight trains.
- A Class 43 power car replacement, which would probably be a conversion of the existing power cars. Everybody loves InterCity 125s and there are over a hundred power cars in regular service on railways in the UK.
There are probably others.
The UK Hydrogen Network Is Growing
Regularly, there are news items about companies in the UK, who will be providing green hydrogen to fuel cars, vans, buses, trucks and trains.
Hydrogen is becoming a fuel with a much higher availability.
The UK Electricity Network Is Growing And Getting More Resilient
We are seeing more wind and solar farms and energy storage being added to the UK electricity network.
The ability to support large numbers of battery-electric buses, cars, trucks and trains in a reliable manner, is getting more resilient and much more comprehensive.
There Will Be More Railway Electrification
This will happen and installation will be more innovative. But predicting where electrification will be installed, will be very difficult.
Hydrogen Fuel Cells Now Have Rivals
Hydrogen fuel cells are normally used to convert hydrogen gas to electricity.
But over the last few years, alternative technology has evolved, which may offer better methods of generating electricity from hydrogen.
- Rolls Royce have developed a beer keg-sized 2.5 MW generator, that could run on hydrogen, which I wrote about in Our Sustainability Journey.
- Honeywell are possibly going the same route, which I wrote about in Honeywell Introduces Power Source For Hybrid-Electric Aircraft.
- JCB have converted diesel engines to run on hydrogen, which I wrote about in JCB Finds Cheap Way To Run Digger Using Hydrogen.
- Caterpiller, Cummins and Rolls-Royce mtu are showing signs of taking a similar route to JCB.
Fuel cells will not be having it all their own way.
Batteries Are Improving Their Energy Density
This is inevitable. and you are starting to see improvements in the fabrication of the battery packs to get more kWh into the space available.
In Wrightbus Presents Their First Battery-Electric Bus, I said this about the Forsee batteries used in the new buses from Wrightbus.
The Forsee brochure for the ZEN SLIM batteries gives an energy density of 166 Wh per Kg. This means that the weight of the 454 kWh battery is around 3.7 tonnes.
A one-tonne battery would have a capacity of 166 kWh.
- It is the highest value I’ve so far found.
- Technology is likely to improve.
- Other battery manufacturers will be striving to match it.
For these reasons, in the rest of this post, I will use this figure.
Some Example Locomotives
In this section, I shall look at some possible locomotives.
Conversion Of A Class 43 Power Car
There are two Class 43 power cars in each InterCity 125 train.
- The diesel engine is rated at 1678 kW.
- The transmission is fully electric.
- These days, they generally don’t haul more than five or six intermediate Mark 3 coaches.
I would see that the biggest problem in converting to battery power being providing the means to charge the batteries.
I suspect that these power cars would be converted to hydrogen, if they are converted to zero-carbon.
- I would estimate that there is space for hydrogen tanks and a small gas-turbine generator in the back of the power car.
- Much of the existing transmission could be retained.
- A zero-carbon power car would certainly fit their main use in Scotland and the South-West of England.
- I doubt hydrogen refuelling would be a problem.
They may even attract other operators to use the locomotives.
A Battery-Electric Locomotive Based on A Stadler Class 88 Locomotive
I am using this Class 88 locomotive as a starting point, as the locomotive is powerful, reliable and was built specifically for UK railways. There are also ten already in service in the UK.
In Thoughts On A Battery Electric Class 88 Locomotive On TransPennine Routes, I started the article like this.
In Issue 864 of Rail Magazine, there is an article, which is entitled Johnson Targets A Bi-Mode Future.
As someone, who has examined the mathematics of battery-powered trains for several years, I wonder if the Age of the Hybrid Battery/Electric Locomotive is closer than we think.
A Battery/Electric Class 88 Locomotive
After reading Dual Mode Delight (RM Issue 863), it would appear that a Class 88 locomotive is a powerful and reliable locomotive.
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- It is a Bo-Bo locomotive with a weight of 86.1 tonnes and an axle load of 21.5 tonnes.
- It has a rating on electricity of 4,000 kW.
- It is a genuine 100 mph locomotive when working from 25 KVAC overhead electrification.
- The locomotive has regenerative braking, when working using electrification.
- It would appear the weight of the diesel engine is around seven tonnes
- The closely-related Class 68 locomotive has a 5,600 litre fuel tank and full of diesel would weight nearly five tonnes.
The locomotive would appear to be carrying between 7 and 12 tonnes of diesel-related gubbins.
Suppose that the diesel-related gubbins of the Class 88 locomotive were to be replaced with a ten tonne battery.
Using the Forsee figures, that I quoted earlier, this battery would hold 1660 kWh.
At the power level of the 700 kW of the Caterpillar C27 diesel engine in the Class 88 locomotive, that would give more than two hours power.
It looks to me, that a battery-electric Class 88 locomotive could be a very useful locomotive.
It might even be able to haul freight trains in and out of the Port of Felixstowe, which would be a big advantage in decarbonising the port.
Certainly, methods to charge battery trains on the move, are being developed like the system from Hitachi ABB Power Grids, that put up short sections of 25 KVAC overhead electrification, which would be driven by a containerised power system.
These systems and others like them, may enable some battery-electric freight trains to work routes like.
- Felixstowe and Ipswich.
- Ipswich and Peterborough
- Peterborough and Nuneaton.
- Peterborough and Doncaster via Lincoln
- Birmingham and Oxford
None of these routes are fully-electrified.
But because of the power limit imposed by the batteries, these locomotives will need to be recharged at points on the route.
This Google Map shows the Ipswich and Peterborough route crossing the Fen Line at Ely station.
Note.
- Ely Dock junction in the South-West corner, where the line from Ipswich and Bury St. Edmunds joins the lines through Ely.
- Ely station towards the North-East corner of the map.
- Passenger trains run through the station.
But freight trains can take a route on the Eastern side of the station, which is not electrified.
At Ely station, a loop like this can be electrified using the existing electrification power supply, but at other places, systems like that from Hitachi ABB Power Grids can be used to electrify the loop or an appropriate section of the route.
These short sections of electrification will allow the train to progress on either electric or battery power.
A Hydrogen-Electric Locomotive Based on A Stadler Class 88 Locomotive
In The Mathematics Of A Hydrogen-Powered Freight Locomotive, I looked at creating a hydrogen-powered locomotive from a Class 68 locomotive.
I decided it was totally feasible to use readily available technology from companies like Rolls-Royce and Cummins to create a powerful hydrogen-powered locomotive.
The Class 68 locomotive is the diesel-only cousin of the electro-diesel Class 88 locomotive and they share a lot of components including the body-shell, the bogies and the traction system.
I suspect Stadler could create a Class 88 locomotive with these characteristics.
- 4 MW using electric power
- At least 2.5 MW using hydrogen power.
- Hydrogen power could come from Rolls-Royce’s 2.5 MW generator based on a small gas-turbine engine.
- 100 mph on both electricity and hydrogen.
- It would have power output on hydrogen roughly equal to a Class 66 locomotive on diesel.
- It would have a range comparable to a Class 68 locomotive on diesel.
This locomotive would be a zero-carbon Class 66 locomotive replacement for all duties.
A Larger And More Powerful Hydrogen-Electric Locomotive
I feel that for the largest intermodal and stone trains, that a larger hydrogen-electric locomotive will be needed.
With the way Wabtec are going in the United States, I wouldn’t be surprised to see a suitable locomotive cross the pond.
Conclusion
In the title of this post, I asked if freight locomotives of the future would be battery, electric or hydrogen.
I am sure of one thing, which is that all freight locomotives must be able to use electrification and if possible, that means both 25 KVAC overhead and 750 VDC third rail. Electrification will only increase in the future, making it necessary for most if not all locomotives in the future to be able to use it.
I feel there will be both battery-electric and hydrogen-electric locomotives, with the battery-electric locomotives towards the less powerful end.
Hydrogen-electric will certainly dominate at the heavy end.
Electro-diesel is the way to go! If the class 73 had a more powerful diesel engine than 600HP then it would be perfect, especially as it can be controlled from most Diesel and electric multiple units, making it good for rescuing broken down passenger trains, freight and high-speed passenger.
Comment by Squid | July 12, 2021 |
I think the HST Intercity 125 BR Class 43 will be converted to hydrogen, Birmingham Uni, BCRRE which was involved in converting with Porterbrook, a dual voltage Class 319 train into a tri-mode hydroFLEX Class 799 and a Severn Valley Railway diesel Class 08 shunter to Harrier HydroShunter, has leased a Class 43 train from Porterbrook. Steamology in 2020 won a £350,000 grant from Innovate UK for R&D of a hydrogen burning gas turbine for trains, I think the first train that will use the gas turbine is the hydrogen version of the Vivarail Class 230 range 650 miles. I think ammonia is better than hydrogen , the energy density is higher, Rail Industry Association Why Rail Electrification ? report page 31 by volume MJ/Litre Diesel 36, Hydrogen ( 700 bar ) 4.8, Hydrogen ( 350 bar ) 2.9, Battery pack -current 1.7, page 49 Liquid Hydrogen 8 and page 50 Ammonia 12.7, the report page 39 claims that a Class 66 loco needs 79 cubic meters of hydrogen which is far higher than your figure of 19 cubic meters for a Class 68 loco and batteries 136 cubic meters weighing 350 tonnes. Ammonia is also cheaper to transport and store as it’s only pressurised to 10 bar not 250 or 500 bar that a IMechE study states ( 350/700 bar is the pressures used in the vehicles fuel tanks not the tanker trucks and storage tanks ) or cooled at only -33 °C not liquid hydrogen -253 °C. RIA WRE ? page 50 rejects ammonia due to safety fears but the wikipedia article mentions ammonia was used to power trams in New Orleans 1870s-80s and Belgium buses burnt a mix of coal gas mostly composed of hydrogen and ammonia 1943-45 because of a shortage of diesel due to WW2 and wikipedia doesn’t write about any accidents and poisonings. I wonder how far an ammonia fueled Class 66 loco could pull a freight train without a tender, my guess is mid range but not long distance.
Comment by jason leahy | July 16, 2021 |
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