The Anonymous Widower

Solar Power Could Make Up “Significant Share” Of Railway’s Energy Demand

The title of this post is the same ass this article in Global Rail News.

This is the first three paragraphs.

Solar panels could be used to power a sizeable chunk of Britain’s DC electric rail network, a new report has suggested.

Climate change charity 10:10 and Imperial College London’s Energy Futures Lab looked at the feasibility of using solar panels alongside the track to directly power the railway.

The report claims that 15 per cent of the commuter network in Kent, Sussex and Wessex could be powered directly by 200 small solar farms. It suggested that solar panels could also supply 6 per cent of the London Underground’s energy requirements and 20 per cent of the Merseyrail network.

In another article in today’s Times about the study, this is said.

Installing solar farms and batteries alongside lines also could provide the extra energy needed to power more carriages on busy routes that otherwise would require prohibitively expensive upgrades to electricity networks.

Note the use of batteries mentioned in the extract from The Times. This would be sensible design as power can be stored, when the sun is shining and used when it isn’t!

If you want to read the full report, click here!

I will lay out my thoughts in the next few sections.

Is This Technique More Applicable To Rail-Based Direct Current Electrification?

All of the routes mentioned for application of these solar farms,; Southern Electric (Kent, Sussex and Wessex), London Underground and Merseyrail are electrified using one of two rail-based direct current systems.

Consider the following.

Powering The Track

In the September 2017 Edition of Modern Railways, there is an article entitled Wires Through The Weald, which discusses electrification of the Uckfield Branch in Sussex, as proposed by Chris Gibb. This is an extract.

He (Chris Gibb) says the largest single item cost is connection to the National Grid, and a third-rail system would require feeder stations every two or three miles, whereas overhead wires may require only a single feeder station for the entire Uckfield Branch.

It would appear that as rail-based direct current electrification needs a lot of feeder stations along the line, this might be better suited for solar power and battery electrification systems.

Consider.

  • Most of the feeder stations would not need a connection to the National Grid.
  • Solar panels generate low direct current voltages, which are probably cheaper to convert to 750 VDC than 25 KVAC.
  • In installing electrification on a line like the Uckfield Branch, you would install the extra rails needed and a solar farm and battery system every two or three miles.
  • With the situation mentioned in the extract from The Times, you might add a solar farm and battery system, to a section of track, where more power is needed.
  • For efficiency and safety, power would only be sent to the rail when a train was present.

I trained as an Electrical Engineer and I very much feel, that solar power and battery systems are better suited to powering rail-based electrification. Although, they could be used for the overhead DC systems we use in the UK for trams.

Modular Design

Each of the solar farm and battery systems could be assembled from a series of factory-built modules.

This would surely make for a cost-effective installation, where capacity and capabilities could be trailored to the location.

Regenerative Braking

Modern trains use regenerative braking, which means that braking energy is converted into electricity. The electricity is handled in one of the following ways.

  1. It is turned into heat using resistors on the train roof.
  2. It is returned through the electrification system and used to power nearby trains.
  3. It is stored in a battery on the train.

Note.

  1. Option 1 is not efficient.
  2. Option 2 is commonly used on the London Underground and other rail-based electrification systems.
  3. Option 2 needs special transformers  to handle 25 KVAC systems.
  4. Option 3 is efficient and is starting to be developed for new trains and trams.

If batteries are available at trackside, then these can also be used to store braking energy.

I believe that using solar farm and battery systems would also enable efficient regenerative braking on the lines they powered.

But again, because of the transformer issue, this would be much easier on rail-bassed direct current electrification systems.

Could Wind Turbines Be Used?

Both solar farms and wind turbines are not guaranteed to provide continuous power, but putting a wind turbine or two by the solar farm would surely increase the efficiency of the system, by generating energy in two complimentary ways and then storing it until a train came past.

Wind energy could also be available for more hours in the day and could even top up the battery in the dark.

In fact, why stop with wind turbines?

Any power source could be used. On a coastal railway, it might be wave or tidal power.

Could Hydrogen Power Be Used?

I think that hydrogen power could be another way to create the energy needed to back up the intermittent power of solar farms and wind turbines.

I put a few notes in Hydrogen-Powered Railway Electrification.

 

Would The Technique Work With Battery Trains?

Most certainly!

I haven’t got the time or the software to do a full simulation, but I suspect that a route could have an appropriate number of solar farm and battery systems and each would give the battery train a boost, as it went on its way.

Would The Technique Work With 25 KVAC Electrification?

It would be more expensive due to the inverter involved to create the 25 KVAC needed.

But I feel it would be another useful tool in perhaps electrifying a tunnel or a short length of track through a station.

It could also be used to charge a train working a branch line on batteries.

Would The Technique Work With Dual Voltage Trains?

Many trains in the UK can work with both third-rail 750 VDC third-rail and 25 KVAC overhead electrification.

Classes of trains include.

  • The Class 319 trains built for Thameslink in the 1980s.
  • The Class 345 trains being built for Crossrail.
  • The Class 387 trains built for various operators.
  • The Class 700 trains recently built for Thamelink.

There are also other classes that could be modified to run on both systems.

Provided they are fitted with third-rail shoes, there is no reason to stop dual-voltage trains running on a line electrified using solar farms and batteries.

The technique could surely be used to electrify a branch line from a main line electrified using 25 KVAC.

Consider Henley Branch Line.

  • It is four-and-a half miles long.
  • It is not electrified.
  • It connects to the electrified Great Western Main Line at Twyford station.
  • The line can handle trains up to six-cars.
  • All services on the line are worked by diesel trains.

Services consist of a shuttle between Henley-on-Thames and Twyford, with extra services to and from Paddington in the Peak and during the Regatta.

Network Rail were planning to electrify the line using 25 KVAC overhead electrification, but this has been cancelled, leaving the following options for Paddington services.

  • Using battery trains, possibly based on the Class 387 trains, which would be charged between Paddington and Twyford.
  • Using Class 800 bi-mode trains.
  • Using Class 769 bi-mode trains.

All options would mean that the diesel shuttle continued or it could be replaced with a Class 769 bi-mode train.

An alternative would be to electrify the branch using third-rail fitted with solar farm and battery systems.

  • All services on the line could be run by Class 387 trains.
  • Voltage changeover would take place in Twyford station.

There are several lines that could be served in this way.

Installation Costs

I’ll repeat my earlier quote from the Modern Railways article.

He (Chris Gibb) says the largest single item cost is connection to the National Grid, and a third-rail system would require feeder stations every two or three miles, whereas overhead wires may require only a single feeder station for the entire Uckfield Branch.

If you were going to electrify, the twenty-four non-electrified miles of the Marshlink Line, with traditional Southern  Electric third-rail, you would need around 8-12 National Grid connections to power the line. As the Romney Marsh is probably not blessed with a dense electricity network, although it does have a nuclear power station, so although putting in the extra rails may be a relatively easy and affordable project, providing the National Grid connection may not be as easy.

But use solar farm and battery systems on the remoter areas of the line and the number of National Grid connections will be dramatically reduced.

Good National Grid connections are obviously available at the two ends of the line at Hastings and Ashford International stations. I also suspect that the electricity network at Rye station could support a connection for the electrification.

This could mean that six to eight solar farm and battery systems would be needed to electrify this important line.

I obviously, don’t have the actual costs, but this could be a very affordable way of electrifying a remote third-rail line.

Which Lines Could Be Electrified Using Solar Farm And Battery Systems?

For a line to be electrified and powered by solar farm and battery systems, I think the line must have some of the following characteristics.

  • It is a line that is suitable for rail-based direct current electrification.
  • It is not a particularly stiff line with lots of gradients.
  • It is in a rural area, where National Grid connections will be difficult and expensive.
  • It has a connection to other lines electrified by rail-based systems.

Lines to electrify are probably limited to  Southern Electric (Kent, Sussex and Wessex), London Underground and Merseyrail.

I also suspect there are several branch lines that could be reopened or electrified using rail-based electrification.

Conclusion

It’s a brilliantly simple concept that should be developed.

It is well suited to be used with rail-based direct current electrification.

It would be ideal for the electrification of the Uckfield Branch.

 

December 6, 2017 - Posted by | Travel | , , , , ,

2 Comments »

  1. […] Zero-carbon power sources for short lengths of electrification as I wrote about in Solar Power Could Make Up “Significant Share” Of Railway’s Energy Demand. […]

    Pingback by Hebden Bridge Station « The Anonymous Widower | December 14, 2017 | Reply

  2. […] This may seem bizarre, but read Solar Power Could Make Up “Significant Share” Of Railway’s Energy Demand. […]

    Pingback by East West Rail To Be A ‘Diesel Commuter Railway’ « The Anonymous Widower | December 17, 2017 | Reply


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