The coalition government in the UK has said before that it is the “greenest government ever”, though this claim has been hard to justify considering the sometimes drastically differing views on climate of the Conservative and Liberal Democrat MPs. However, it seems the government has finally made good on this statement, by announcing huge reforms within the public transport sector, especially the rail network. The transport secretary Justine Greening has put forward a £9.4bn, a significant proportion of which will go towards the electrification of existing railway lines. Plans include:
- An £800m electrification of the line between Bedford, East England and Sheffield, Yorkshire, which will also complete the electrification of connecting lines between the East Midlands and St Pancreas Station, London.
- Two-thirds of the Welsh population having access to an electric train via a £600m revamp of the welsh valley lines to Swansea
- An ‘Electric spine’ running down the centre of Britain, linking Yorkshire, the Midlands and London more than ever before
Given that Britain has the most expensive rail network in Europe, it is hoped that not only will the further electrification of the rail network reduce British carbon emissions, but also reduce travelling costs. These changes are set to be completed by about 2019. But just how clean are electric trains? This article aims to weigh up the potential environmental benefits and issues related to electric trains.
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Electric trains are being given a huge monetary boost by the British Government, in an effort to become a greener government. Image Credits: Photos.com
Theory and History behind Electric Trains
As the name suggests, electric trains are powered by electricity rather than the traditional fossil fuels of diesel and coal. The electricity is initially generated in large-scale power stations, such as those that supply household electricity. Therefore the electricity may be generated via any energy source, from coal to hydroelectricity depending on the power station. This is then transferred to the locomotive via several different methods.
The two main ways in which an electric train is supplied with power are rechargeable storage batteries or, more commonly, via a stationary source, usually an overhead wire or a third rail. The 3rd rail method usually supplies DC electricity via a rigid conductor along the side of the railway track. Many overhead wire systems across Europe use 1500 Volts DC, though in Britain this is used solely in the Tyne and Wear Metro system.
Once the electricity reaches the train, power is transferred to the train via a contact conductor, which in an overhead wire configuration is a ‘pantograph’ (electric rod) attached to the roof of the train. This then drives the train wheels via the motor.
The first electric passenger train was engineered by Werner Von Siemens in 1879 and initially electric trains were used solely for underground systems where pollution from steam trains could be a hazard.
Italy was the first country to introduce a length of public electrified train track in 1901, though it wasn’t until the 1960’s that there was widespread electrification of Europe’s railways. Electrification of trains was revived in the 1980’s as the Japanese Shinkansen and French TGV ushered in a new era of high speed trains.
What Are the Environmental Benefits of Electric Trains?
As with all electric vehicles, there are significant cuts in carbon emissions when using electric trains as opposed to diesel or steam driven trains-pollution from the train itself is essentially zero. On top of this, the electricity is generated from a power plant, and though the power from these can come from non-renewable sources, this is still cleaner than using mobile coal and diesel sources. The Department for Transport (DfT) claims that carbon per passenger mile from an electric train is up to 35% less than that produced from a diesel train.
Furthermore, electric trains have lower energy and maintenance costs, which in turn can lead to cheaper train tickets. Electric trains also cause less wear to the track due to fewer reciprocating parts in comparison to traditional trains. A further advantage is that the electric motors in the train are highly efficient, with efficiency regularly around 90%. Recent advancements in efficiency include regenerative braking, which can be used to recover energy from braking, via motor-inverter drive systems.
Issues with Electric Trains
A major issue with electric trains is the cost of the infrastructure, though this is more of an issue in the United States than it is in Europe, as the infrastructure of the USA rail network is privately owned, and therefore it is currently still more economically viable to use predominantly diesel locomotives. Another issue is that some people believe an increase in overhead cables to be detrimental to the beauty of the surrounding countryside.
It had been suggested that as the speed of an electric train increases, then its advantage with regards to sustainability over other methods of transportation will diminish. However, it has recently been suggested that an electric train travelling at 300km/h would still have fewer carbon emissions per passenger than a diesel train traveling at a speed of 220km per hour.
Sources and Further Reading
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