StKeverne1497
Member
To provide battery EMUs to replace every one of the c5000 non pure EMU passenger vehicles on the network, with enough range for about an hour off the wire, would need roughly 750MWh of battery capacity. That‘s what Tesla produce every day for their cars.
I'm not sure that adds up, even if I'm right to assume you mean individual vehicles rather than "trains", and ignoring those trains that have unpowered vehicles.
750MWh divided by 5000 vehicles is 150kWh per vehicle. Elsewhere it looks as if a typical DMU uses about 10 times the amount of Diesel per mile as a car would. If you assume double the efficiency for a BEMU because of regeneration (no idea if that's an appropriate figure) and apply the resulting ratio (5 times the amount) to a rail vehicle, that's the equivalent of about a 30kWh battery in a car. Is that really enough for an hour of stop-start driving, fast acceleration and 60 - 75mph top speeds?
I mean, by my back-of-the-envelope you're possibly in the right ballpark if my assumptions are reasonable, but it's right at the low end I'd think.
The other question is whether a typical BEMU will need an hour of off-wires running. I gather TfW probably will, as the stretch between Queen Street and Penarth (for example) will not be wired, but is that a "normal" situation in the rest of the country , or is it more likely to be a few much shorter stretches, as happens north of Queen Street?