Nottingham59
Established Member
To understand the implications of converting regional train services to battery or tri-mode operation, I thought it would be useful to consider what range and endurance would be possible with current battery technology. EMR use class 170s, so I'm going to propose a battery trimode for regional trains, based on a 3-car 170 (3x23m carriages; top speed 100mph; 3 x diesel engines rated at 315kW; acceleration 0.5m/s^2).
PROPOSED REFERENCE TRIMODE TRAIN
TRACTION POWER
Ignoring hotel power for now, I'm going to assume that average consumption of traction energy is between one third and one half of the peak total power of a 170 (which is 945kW). This is based on the 2021 record attempt, where 390044 used 8MWh to get from London to Glasgow in 4 hours. Average consumption at 2MW was 40% of the 5.16MW peak power of a 9-car Pendolino. If anyone has any better data for traction energy consumption by regional passenger stock, please share it.
The gives an assumed average power consumption, ignoring hotel power and after the effect of regenerative braking, of
RANGE WITH JUST EXISTING OHLE ELECTRIFICATION
Do you agree? Have I missed anything?
Now, interesting things happen when you start to add islands of electrification at places like Nottingham and Sheffield. But I'll look at those in another post, possibly tomorrow.
PROPOSED REFERENCE TRIMODE TRAIN
- one 315kW diesel engine, as on a 170. Able to use diesel fuel or HVO biodiesel.
- two 575kWh Turntide battery packs, as fitted to 802207 in the Hitachi tri-mode trial.
- maximum 2C recharge rate = 1.15MW per battery, when between 20% and 80% state of charge. Giving an operating recharge time (20% to 80%) of 575/1150 x60% = 0.3h (18 minutes)
- max electric power uptake on 25kV AC of 4MW, with a second pantograph below 10mph to keep within the 2MW per pantograph limit when stationary
- Plug-in charging at terminus platforms, using the MCS Megawatt Charging Standard for EV trucks (up to 3.75MW)
TRACTION POWER
Ignoring hotel power for now, I'm going to assume that average consumption of traction energy is between one third and one half of the peak total power of a 170 (which is 945kW). This is based on the 2021 record attempt, where 390044 used 8MWh to get from London to Glasgow in 4 hours. Average consumption at 2MW was 40% of the 5.16MW peak power of a 9-car Pendolino. If anyone has any better data for traction energy consumption by regional passenger stock, please share it.
The gives an assumed average power consumption, ignoring hotel power and after the effect of regenerative braking, of
- 472kW (50% of peak) on fast mainline routes like Nottingham - Cardiff and Nottingham - Leeds
- 315kW (33% of peak) on slow provincial routes like Nottingham - Skegness and Nottingham - Workshop
RANGE WITH JUST EXISTING OHLE ELECTRIFICATION
- On slow provincial routes, maximum range on battery alone will be 2x575/315 = 3.65h, with an operating endurance (from 80% charge to 20%) = 60% x 3.65h = 2.2h. Enough to get from Nottingham to Matlock and back.
- With the diesel engine, range is unlimited. One 315kW engine will match the assumed averge consumption, with the battery packs absorbing the peaks and troughs of energy use. One engine running at a steady speed will have lower diesel consumption and very much lower maintenance costs than three engines on a 170 running a typical DMU load cycle.
- On fast lines, battery-only range will be 2x575/472 = 2.4h (max) x60% = 1.46h (operating). 1.4h is enough to get from Severn Tunnel Junction onto the wires at Bromsgrove; and from Proof House junction to Nottingham (but not back again).
- On fast lines with the diesel engine running, endurance will be 2x575/(472-315) = 7.3h (max) x60% = 4.4h (operating endurance). Enough to get from Leeds to Nottingham via Barnsley and back. If the Leeds-Nottingham service went via Moorthorpe, it would have 40-50 minutes under the wires; plenty of time to fully recharge the batteries.
Do you agree? Have I missed anything?
Now, interesting things happen when you start to add islands of electrification at places like Nottingham and Sheffield. But I'll look at those in another post, possibly tomorrow.
