The city of Barcelona is utilizing the regenerative braking system of its subway trains to power trains, stations, and electric vehicle charging points in the neighborhood.
Most passengers exiting the station in Bellvitge, a working-class neighborhood on the outskirts of Barcelona, are unaware of how advanced the city’s subway system truly is. Using technology similar to regenerative braking found in electric and hybrid vehicles, the trains they ride generate a portion of the electricity that feeds into nearby electric vehicle charging stations, lights up the station, and powers the elevators that take them to the platforms, according to Popsci.
Every time a train prepares to stop, the energy generated by all the friction is converted into electricity, which is then channeled to inverters and distributed throughout the subway system. One-third of that electricity helps to run the trains, while the remainder is used for station amenities and the expanding network of EV charging points.
Subway in Barcelona. (Photo: TEFL).
Super-fast charging points outside the Bellvitge station are among four charging stations installed last July. The city’s primary transit provider, Transports Metropolitans de Barcelona (TMB), plans to add three more charging points as the MetroCHARGE project expands. “We are trying to harness electricity from the subway system and use that surplus energy for street electric vehicle charging points,” said Marc Iglesias, head of sustainable transport at the Àrea Metropolitana de Barcelona, the regional agency working with TMB on the project.
Each year, residents and tourists make 440 million trips on Barcelona’s subway system, which includes 165 stations connected by 125.5 kilometers of track. To date, the transportation agency has installed three inverters and will add 13 more. After all installations are completed by the end of September, they hope that regenerative braking will provide 41% of the energy needed to operate the trains. This renewable energy source is expected to reduce CO2 emissions by approximately 3.9 tons annually.
While many cities, including Vienna, Philadelphia, and São Paulo, utilize regenerative braking to some extent, Barcelona is among the few cities that employ it extensively and is the first to harness that energy for electric vehicle charging infrastructure. Capturing energy that would otherwise be lost as heat when trains slow down can significantly reduce the electricity consumption of the public transport system.
With the implementation of MetroCHARGE, 33% of the energy used by trains comes from regenerative braking, sufficient to power 25 subway stations, according to Jordi Picas, project director and head of the subway system at TMB. In subway systems that do not employ regenerative braking, too much energy goes unused, not only wasted but also generating excess heat within the tunnels, raising temperatures. Since implementing regenerative braking, the temperature within Barcelona’s subway system has decreased by one degree Celsius. Although the implementation of MetroCHARGE costs around $8.6 million, TMB hopes to recover this investment within 4 to 5 years through energy savings and revenue from charging points paid for by drivers.
Other subway systems worldwide have the necessary electrical infrastructure to adopt this approach, but not all operate trains equipped with regenerative braking, and modifying trains can be quite costly. All trains in Barcelona have been equipped with this technology since the 1980s. Assuming each train costs approximately $6.6 million and has an average lifespan of 35 to 45 years, transit operators need to include regenerative braking in their mid- to long-term plans.
In addition to costs, there are many other challenges, such as finding optimal locations to install inverters and charging points in densely populated urban areas. The biggest challenge is reaching agreements with city councils to access public space for placing charging points.
One of the main barriers to implementing regenerative braking is the lack of data on energy levels and the potential savings from using the technology. Learning from projects like MetroCHARGE can help cities understand the benefits of regenerative braking.
