Siemens Mobility Tests Regenerative Braking on Athens Line 1

ATHENS, GREECE – STASY, the operator of Athens’ metro and tram networks, and Siemens Mobility began trial operation of a regenerative braking energy recovery system on Metro Line 1 at the Neo Faliro traction substation in mid-July. The €4.1 million project is expected to recover 4,500 MWh annually, equivalent to 12.5% of the line’s electricity consumption. A second unit is due to be commissioned at the Iraklio traction substation before the contractual deadline in December 2026.

What Are the Technical Specifications?

The Athens Line 1 system captures kinetic energy from braking trains, converts it to electricity, and feeds it into the power grid for use by other trains or railway facilities. When a train brakes, its electric motors temporarily function as generators; instead of dissipating the energy as heat, the new equipment converts it and returns it to the network. The project also includes modernisation of both Neo Faliro and Iraklio traction substations, and is funded through the Greek development programme ESPA. STASY has not disclosed the system’s per-substation power rating or the expected annual euro savings from reduced electricity purchases.

Key Technical Data

Where Does This Technology Stand in the Market?

The Athens pilot’s projected 4,500 MWh annual recovery is part of a broader Greek urban rail sustainability push in which Thessaloniki’s first driverless metro, delivered by Hitachi Rail, is expected to remove 56,000 commuter cars daily and save 77,000 tonnes of CO₂ annually (Source: Hitachi Rail / RailwayPRO, 2025).

Competing energy recovery systems are already established elsewhere: Alstom’s HESOP reversible substation has been deployed on metro systems including London Underground, while ABB’s Enviline ERS is used on DC rail networks in Europe, the Middle East and Latin America (Source: Alstom / ABB, 2023). Siemens Mobility’s Athens installation is smaller in scale — two substations and €4.1 million — but it is positioned as the first on a Greek railway network, giving STASY a local benchmark for future expansion.

Separately, Greece’s conventional rail network density was 14.0 m/km², the lowest in the EU, but the share of multiple-track lines rose from 9.9% in 1990 to 35.5% in 2024 (Source: Eurostat, 2024). This makes energy recovery on existing metro corridors such as Line 1 a critical part of the country’s rail efficiency strategy.

Editor’s Analysis

Regenerative braking is shifting from an optional efficiency add-on to a baseline requirement for EU-funded metro modernisation. STASY’s pilot is small — two substations and 12.5% of one line’s consumption — but it gives Athens a measurable case study for wider deployment across Lines 2 and 3 and the tram network. With the autonomous train market projected to grow at a 6.9% CAGR from 2025 to 2034 (Source: GM Insights), energy recovery and digital traction power management are likely to be packaged together in future Greek urban rail tenders.

FAQ

Q: How much energy will the Athens Metro Line 1 system recover annually?
A: STASY estimates 4,500 MWh per year, equal to 12.5% of Line 1’s annual electricity consumption.

Q: Who is installing the regenerative braking system and what does it cost?
A: Siemens Mobility is implementing the system for STASY under a EUR 4.1 million contract funded by the Greek ESPA development programme.

Q: Will the regenerative braking system affect passenger service or fares?
A: STASY has not officially confirmed any fare changes; the project is intended to reduce operating costs and improve power supply reliability at Neo Faliro and Iraklio substations.