The London Underground planned on five weeks of tests to see how much energy it could collect when the trains braked on their approach to a substation. Just one week into the trial, the potential benefits of recycling energy were so strong that the city is already looking to step on the gas to expand the program.
"The results of this project are really exciting and show huge potential for harnessing some of the immense energy in our Tube trains," said London Deputy Mayor for Environment and Energy Matt Pencharz. "The trial puts London at the cutting edge of this kind of technology and clearly demonstrates how energy from trains can be recovered to power Tube stations, making the network more environmentally friendly and cost-effective."
The trial involved installing a new inverter system at the Cloudesley Road substation on the city’s Victoria Line. The inverter reclaims energy that would normally be lost when the subway is braking. In just the first week of the project, enough energy was reclaimed to power the large train station for two days.
Reduced carbon footprint, millions in savings
Technically, the recycling process is referred to as regenerative braking. City and transportation officials are excited about its potential for good reason. Transport for London (TfL), which manages most transportation in Greater London, said in a statement that London Underground could take advantage of what was a previously unavailable source of energy to reduce its carbon footprint and save as much as ₤6 million (US$9 million) annually to reinvest in the transportation system.
The project fits well with others transit and city officials have undertaken to modernize and increase capacity and efficiency for the city's transport system. Early this year, the Greenwich Power Station was upgraded with new gas engines replacing old boilers to generate cleaner, cheaper electricity for Tube operations -- with waste heat from the engines shuttled to a new local heat network.
TfL, the world's largest pay-as-you-go network, has made several improvements designed to make getting around London smoother and more efficient for riders. As of fall 2014, riders can use their contactless debit, credit or pre-paid cards from Council Lead Partner MasterCard to board buses and trains.
Council Lead Partner Microsoft provided its cloud services to TfL so the agency could develop citizen-focused web apps and manage the more than two million hits its web site gets daily. And Lead Partner Cubic Transportation Systems was awarded a contract in August to provide ticketing and fare collection services.