Barcelona is turning subway trains into power stations
Barcelona is turning subway trains into power stations
grist.org
Barcelona is turning subway trains into power stations
19 comments
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It also reduces brake wear on the trains, so they'll need new brakes less often, and it improves air quality in the stations. Most of that black dust you see is brake dust. And you're breathing it in, too.
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Why can't they use the excess energy to make the train go again?
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They do... 1/3rd of it is used that way.
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Leaving the train at 1/3rd the speed it decelerated from?
What's really happening:
- Barcelona want to use regen braking to reduce power usage of their metro - this is good.
- Adding batteries to store all that energy for 30seconds at each stop is impractical in some way. It makes the train too heavy / They can't charge quick enough / The charging loss is too high. So, they go for a smaller battery.
- The electrical grid gets the rest of the energy dumped into it, only to supply it back to the train when it accelerates again. They use the grid like a battery.
- Some public relations person heard this and issued a press release - "Barcelona using metro as power station".
- Every engineer working on the project simultaneously groans in despair. The resulting low frequency wave shakes the foundations of Sagrada Família, setting the construction back another generation.
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19 comments
Are they generating more power than they are spending by making the train go? Has Barcelona mastered perpetual motion??
It's good thing, sure, but it's no savior. The blurb makes it sound like it's a net gain of energy, and that's impossible. It's not free energy. It's just upcycled waste.
I don't read it as magical energy created out of nothing, but I do read it as "free" energy that would exist whether this regeneration system is used or not, that would otherwise be lost as heat.
With or without regenerative braking, the train system is still going to accelerate stopped trains up to operational speed, then slow them down to a stop, at regular intervals throughout the whole train system. Tapping into that existing energy is basically free energy at that point.
Only because of the speed of the train. Fuel spent accelerating to later brake is wasted fuel. More efficient would be spending only enough fuel to come to a full stop without braking.
It reduces waste, yes.
Sure, and that's not a bad thing. But what is revolutionary and newsworthy about what Barcelona is doing?