crs1026
Superstar
The amount of electricity a fleet of trains uses is minuscule compared to the total electricity produced. I am not sure about other regions, but the Total Annual Ontario Electrical Energy Demand in 2019 (I'll ignore 2020 because of COVID) of 135.1 TW was 14% below the peak demand of 157 TW in 2005.
To carry this a bit further, the granular data on where power comes from hour-by-hour can be found at http://reports.ieso.ca/public/GenOutputCapability/PUB_GenOutputCapability.xml.
A single VIA locomotive, with HEP, represents about 4 Mw at full power. A single freight locomotive is similar.
So yeah, on any given day, even at peak there is already enough electricity in reserve on the Ontario grid to power many hundred locomotives at full power, without anybody's lights blinking. With regenerative braking, that demand can be mitigated.
I do think that some sort of storage technology will factor into railways' electrification, so that power can be stored at low demand times and drawn down during peak periods, so that railway propulsion doesn't strain Ontario's electricity supply.
And this assumes that power will come from the grid. There is so much room for freestanding supply these days.
- Paul




