You've probably heard plenty about regenerative braking when it comes to hybrid and electric cars. Those vehicles are outfitted with technology that captures the energy usually wasted as heat during braking and feeds it back to the battery to increase a vehicle's range.
A trial of a new regenerative braking technology in London has taken that idea and super-sized it for the city's Tube trains. Using an inverter energy capture system, the new technology recovers the energy from the trains' brakes and sends it back to the mains as electricity. In a train system as large and as heavily-trafficked as the London Underground, the energy savings from this technology add up quickly.
The city just recently tested the technology at Cloudesley Road substation on the Victoria line and found that it could capture 1MWh per day, which is enough to power about 104 homes per year. That shaves five percent off the energy bill for the London Underground -- saving as much as £6 million every year. During the trial, the system captured enough energy in a week to fully power the Holborn Station for two days a week.
The system will also have additional energy saving benefits not measured in the study. Since the system captures the energy from braking that would otherwise be wasted as heat, the trains will be creating less heat and the stations will need to run their cooling systems less.
The new technology is part of a bigger project by Transport for London to make the public transportation system more energy efficient and lower its carbon footprint.