What is the energy change in an electric train?

Answer 1

Hi

I'm trying to estimate how much electricity a new high speed train in the UK would use to go at 400 km/h and how many wind turbines it would require to run it. My physics is a bit rusty so I'd appreciate it if someone would check my calculations.

It is difficult to estimate how much energy these trains would draw down from the electric grid. Actual consumption will depend on the weight of the trains, gradients, maximum speeds and stopping patterns. Data produced for the European MEET project illustrates different consumption patterns over several track sections. Results for the consumption by German ICE high-speed trains which have a service speed of 330 km/h fluctuate from around 19-33 kWh per km.

Therefore, for estimation purposes I propose to split the difference and say they consume 25kWh per km.

2 questions

1. If a train consumes 25kWh per km and a wind turbine generates 1000kWh on average, how many wind turbines would be required to run at 330 km/hr? Would it be 25 x 330 ÷ 1000 = 8.25 ???

Yes, that is correct. Check the units: (25 kWh/km)(330 km/h)= 8250 kWh/h= 8250 kW.

You have said that a wind turbine generates 1000 kWh. Two comments:

#1-The units for a wind turbine should be 'kW when it's running', and

#2-That sounds like a large number for a single wind turbine.

But assuming for the moment that the number is accurate, then 8250 kW is

indeed the output of 8.25 wind turbines.

2. Also, would it be true to say that because energy use rises with the square of speed, trains operating at 400 km/h would use one and a half times more energy than at 330 km/h and require 8.25 x 1.5 = 12.375 wind turbines ???

Well, 400/330= 1.2121... and its square is about 1.47 so yes, it would take about 1.5 times as much.

Please let me know if this is right or wrong.

Answer 2

Electricity is changed to kinetic energy by causing the train to move. Electricity in the motor causes a force to be applied to the armature and transferred through a drive system to apply a motive force which results in motion.

Answer 3

Most trains now use electrical energy, some use diesel engines so that is chemical energy.

Answer 4

A maglev train uses magnetic propulsion to glide along the tracks so it never makes contact with the tracks or the sides. It also uses elctronic pulses to keep it moving.