Trains on the future Line 6-Orange of the São Paulo Metro will feature a regenerative braking system capable of capturing the energy generated during deceleration and returning it to the metro's electrical grid.
The technology, considered a milestone in energy efficiency in Brazilian public transportation, reduces electricity consumption and extends the lifespan of mechanical systems, in addition to paving the way for cleaner and more economical urban mobility.
Manufactured by Alstom in the city of Taubaté, São Paulo, the trains are 100% Brazilian and represent the new generation of metro vehicles. The first of them has already been delivered to Pátio Morro Grande, in the northern part of the capital, and marks the beginning of the testing phase of the line, which will be 15,3 km long and connect Brasilândia and São Joaquim, with partial operation scheduled for 2026.
The innovation also brings operational benefits, such as reduced brake wear, reduced noise, and increased thermal efficiency of internal systems. Learn more below:
How much % of kinetic energy can be converted and reused in the efficiency of the train's regenerative braking system?
The electric traction and braking system utilizes advanced technology with high-efficiency inverters of up to 99%. This means that during typical train operation, approximately 50% of the energy used by the train can be regenerated.
How is regenerated energy transferred to other trains? Does the system use a shared DC (direct current) grid, a capacitor bank, or is there temporary storage?
Within the rolling stock, the energy generated by the electric brake can be directed to the 1500 VDC (Volts Direct Current) network, the catenary, provided it is receptive, for example, being consumed by other trains. In cases where the network is not receptive, the generated energy is dissipated within the train itself through resistor banks. The 1500 VDC network is considered receptive if the overhead line's electrical infrastructure (catenary) is capable of receiving and absorbing the electrical energy regenerated by the train during braking, ensuring that the voltage does not exceed its upper limit.
Under what operating conditions is regeneration most effective? Does efficiency vary depending on speed, track gradient, or the number of trains running?
Within the rolling stock, regeneration efficiency is optimized for each point depending on the required effort. During typical operation, in the speed range between 10 and 70 km/h, regenerative braking can account for up to 100% of the required deceleration effort, assuming the 1500 VDC network is receptive. A greater number of trains in circulation will contribute to a more receptive network.
Does regenerative braking have a positive impact on the maintenance of mechanical brake systems? Is there any expectation of a reduction in brake wear or maintenance costs?
Yes, regenerative braking reduces the need for mechanical brake actuation, reducing wear on consumables such as brake pads, and also reducing system utilization, extending its lifespan. During typical operation, in the speed range between 10 and 70 km/h (100 and XNUMX mph), regenerative braking can account for up to XNUMX% of the required deceleration effort.
Is there an energy management system that will control the distribution and use of regenerated energy on the line, such as EMS (Energy Management System) or SCADA (Supervisory Control and Data Acquisition)?
The energy infrastructure is not managed by Alstom. However, the regenerated energy is generally consumed by other trains.
If the regenerated energy isn't immediately "demanded" by other trains, what happens to the excess? Is it dissipated, stored, or returned to the utility grid?
Within the rolling stock, in cases where the network is not receptive, the energy generated is dissipated in the train itself, through resistor banks.
What is the expected annual energy savings provided by the regenerative system?
Energy consumption depends directly on the use of trains in operation (quantity, frequency, etc.). This operation is not managed by Alstom.
Does stainless steel, the material used in trains, directly impact energy consumption by reducing weight?
This type of material, because it's highly resistant to corrosion, is especially suitable for extreme environmental conditions, such as high humidity, salinity, and temperature variations. Our solutions have been optimized and developed over many years of experience, utilizing high-strength materials and spot welding technology. This results in designs with high structural efficiency and reduced weight. Furthermore, the train interiors feature thermal insulation that increases the efficiency of the air conditioning system, reducing energy consumption.
Was the origin of the regeneration technology used developed in Brazil by Alstom or does it integrate international solutions adapted to the local context?
The Electric Traction and Braking System is technology developed by Alstom, led by our specialized unit located in Charleroi, Belgium, but with the participation of other units around the world, including our team of experts located in Brazil.
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