While modern electric cars have only been available in large numbers for a few years, electric trains have been commonplace for some time.
As with electric cars, the source of the electricity used to power these trains impacts their overall carbon footprint.
The cleaner an energy source, the cleaner the vehicles it powers.
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In that respect, The Netherlands may be setting the standard.
The 600,000 daily passengers trains are supplied with 1.2 billion kilowatt-hours of wind energy by Eneco per year, as part of an arrangement with NS first announced in 2015.The two companies originally planned to transition Dutch electric trains to 100-percent renewable energy by 2018, but moved up the timetable after achieving 75-percent renewable-energy use last year.
Power from the rail network comes from wind farms not only in The Netherlands, but also Belgium and Scandinavia, according to Eneco.
Sourcing power from multiple countries ensures that there is an adequate amount of electricity for the rail network's needs at all times, Eneco said in a statement.
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The intermittent nature of many renewable-energy sources has led to some concern over what to do when the wind isn't blowing or the sun isn't shining.
Energy-storage systems that use lithium-ion battery packs to store excess power for later use are one solution touted by renewable-energy proponents.
The Netherlands currently has 2,200 operable wind turbines, with plans for a large new offshore wind farm as well.
Dutch NS electric train by Flickr user Riel Hemkes (Used under CC License)
In addition to the renewable-energy initiative, NS is in the process of reducing its overall energy consumption by 2 percent per year, having already achieved a 30-percent reduction from 2005 levels.
While the use of renewable energy to power electric trains is impressive, it does not account for all of the trains operating on the Dutch rail network.
A small number of trains—likely for freight service—are still diesel powered.
Dutch NS Sprinter electric train by Flickr user Alfenaar (Used under CC License)
That's because the greater infrastructure demands of electric trains limit where it is practical to use them.
Electric trains get their power from overhead wires or an electrified "third rail," installation costs of which must be factored into any decision to operate them on a given rail line.