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Mind the amp! Tube recharges with braking energy



New technology recycles enough energy from Tube trains to power stations

A world-first trial of technology to collect waste energy from Tube train brakes has captured enough power to run a large Underground station – opening the way for significant savings, London Underground claims. The technology is regenerative braking - essentially, switching an electric motor to act as a dynamo so that it acts as a brake while converting the train’s kinetic energy into electrical energy rather than heat.

The basic idea is not new - trains on several London Underground lines use the principle to save energy and generate less heat - but the new scheme on the Victoria line has demonstrated that it is possible to return power to the grid.  A five-week trial of the system at the Cloudesley Road substation near King’s Cross on the Victoria line showed that the technology recovered enough power to run a station as large as Holborn for more than two days per week.

Carbon footprint

London Underground said the results show that tapping into a previously inaccessible resource could its carbon footprint and save £6m a year. The results indicated that 1 megawatt hour of energy can be captured per day – enough to power 104 homes per year.

Chris Tong, London Underground’s head of power and cooling, said: “This state-of-the-art regenerative braking system has the potential to transform how we power stations across the TfL network, unlocking massive power savings and significantly reducing our energy bills. We are committed to doing more to reduce our energy use, and this technology – a world first for metro railways – is one of a number of innovations we’re embracing to lower our environmental impact.”

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