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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.
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.
It’s also the default for commuter trains, they pretty much all do it.
Regenerative braking on commuter trains is nothing new, it’s been around for decades.
And even in some prototype bus, the Gyrobus, in the 50’s that used an electrically charged flywheel that was also (to some degree) regeneratively recharged when breaking:
Rather than carrying an internal combustion engine or batteries, or connecting to overhead powerlines, a gyrobus carries a large flywheel that is spun at up to 3,000 RPM by a “squirrel cage” motor.[1] Power for charging the flywheel was sourced by means of three booms mounted on the vehicle’s roof, which contacted charging points located as required or where appropriate (at passenger stops en route, or at terminals, for instance). To obtain tractive power, capacitors would excite the flywheel’s charging motor so that it became a generator, in this way transforming the energy stored in the flywheel back into electricity. Vehicle braking was electric, and some of the energy was recycled back into the flywheel, thereby extending its range.
Source: Wikipedia: Gyrobus
That’s incredible.
Agreed, but here it is done highly effective. The 1.8 degree temperature difference is a huge plus too - they can now also save serious amounts of power on ventilation.
TfL, you listening?The heat on the underground is mad, makes it so hard to dress for the weather. Go out in a coat because it’s cold then get down on the central line and everyone is sweating hard
The warming is global, tubes included.
Agreed. I think TfL actually has begun looking into it but it’ll probably take years before the temperature is going to drop.
Why can’t they use the excess energy to make the train go again?
They do… 1/3rd of it is used that way.
Leaving the train at 1/3rd the speed it decelerated from?
What’s really happening:
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Barcelona want to use regen braking to reduce power usage of their metro - this is good.
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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.
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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.
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Some public relations person heard this and issued a press release - “Barcelona using metro as power station”.
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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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