Madrid, December 16, 2025 – The Municipal Transport Company of Madrid (EMT Madrid) is leading the charge in sustainable urban transport with an innovative project focused on extending the lifespan of electric bus batteries. This initiative, developed in partnership with Iberdrola and Irizar e-mobility, involves reusing traction batteries for static energy storage, supporting the recharging infrastructure for its growing electric fleet. The project was showcased this morning at the Fuencarral Operations Center, with a visit from Borja Carabante, Delegate for Urban Planning, Environment, and Mobility.
Pioneering Battery Second-Life for Sustainable Mobility
The core of this pioneering project lies in repurposing electric bus batteries that, due to natural aging and a reduction in their storage capacity, are no longer optimal for vehicle traction. These ‘second-life’ batteries are integrated into a static electrical energy storage container, providing a practical and economic solution for battery charging while significantly contributing to environmental sustainability and the circular economy.
Batteries are a critical component of electric buses, directly influencing vehicle autonomy. Daily recharging cycles gradually diminish their capacity, necessitating replacement to maintain optimal bus performance. This project addresses the significant challenge of maximizing battery utility beyond their initial operational life.
Smart Charging Integration and Environmental Benefits
EMT Madrid plans to utilize these second-life batteries as a crucial element within its smart charging system. This integration aims to optimize the recharging process and reduce associated costs. The storage container, which boasts a maximum storage capacity of 1 MWh and a charge/discharge power of 500 kW, is recharged during periods of optimized electricity prices, promoting the use of green energy. It comprises three battery racks, sourced from three retired EMT Madrid vehicles. The container can be managed through EMT Madrid’s existing smart charging system, which already serves the daily recharging needs of the electric bus fleet at the Fuencarral Operations Center.
Beyond the economic advantages, the project underscores a strong commitment to environmental responsibility. By extending the useful life of batteries, the need for manufacturing new ones is reduced, leading to a decrease in raw material consumption and a lessened environmental and social impact. This initiative fosters cleaner, more efficient, and responsible public transport, and holds potential for a more flexible and renewable electrical system in the future.
Collaborative Effort for a Greener Future
Iberdrola, acting as the energy partner, has collaborated closely with EMT Madrid on the technical specifications and field validation of the prototype. Their objective is to reduce costs and enhance efficiency through battery optimization. Irizar e-mobility, as a strategic partner, was responsible for the design and development of the second-life battery energy storage container.
EMT Madrid’s Electrification Journey
The decarbonization of public transport in Madrid and the broader transition to cleaner mobility are key objectives for both the City Council and EMT Madrid. This ambitious goal is supported by three pillars: the acquisition of zero-emission buses, the adaptation and construction of sustainable infrastructure at the municipal company’s operations centers, and the implementation of cutting-edge technologies in mobility and clean energy.
Currently, EMT Madrid operates a fleet of 452 electric buses and manages 410 charging points (250 pantographs and 160 plug-in chargers) across its operations centers in Carabanchel, Fuencarral, Entrevías, and Sanchinarro. Furthermore, to ensure optimal economic and environmental conditions for this electrification, EMT Madrid is developing a smart digital electric bus charging system at its Fuencarral Operations Center. This system enables more efficient, sustainable, and 100% automated recharging, currently serving 20 connected electric buses. Its purpose is to maximize charging while minimizing power consumption and optimizing electricity usage during different tariff periods.
Source: https://www.madrid.es/portales/munimadrid/es/Inicio/Actualidad/Noticias/EMT-Madrid-pionera-en-extender-la-vida-util-de-las-baterias-de-sus-autobuses-electricos/?vgnextfmt=default&vgnextoid=d5192f77fa62b910VgnVCM100000891ecb1aRCRD&vgnextchannel=a12149fa40ec9410VgnVCM100000171f5a0aRCRD
