Smart electricity exchange and synergies between the grid and railways
The power distribution grids and light railway electrification systems are both robust grids developed and operated as independent networks. Increasing penetration of renewable energy sources (RES) into both has created challenges in dealing with fluctuations. Both are looking at integrated solutions to reduce electricity losses, increase grid stability and accommodate new actors in the energy area, such as storage systems, electric vehicles (EVs) and prosumers (both producers and consumers of energy). Despite these common goals, there is currently no system available for a smart exchange of electricity between the two networks. The pioneering EU-funded E-LOBSTER project delivered such system.
Innovative asset sharing, monitoring and control
E-LOBSTER developed two assets to be shared, a smart soft open point (sSOP) device and a battery energy storage system. SOPs are a relatively new type of power electronic devices whose flexibility, rapid response and resiliency are well-suited to distributed generation and increasing RES penetration. The battery energy storage system enhances the flexibility and efficiency of the interconnection between the two networks. According to Giannicola Loriga, Head of Corporate R&D Networking & Development Strategy at RINA and E LOBSTER coordinator, “the sSOP developed in the project is based on power converters to interface power distribution networks and railway electrification systems. This allows unique management of the energy between traction substations of light railway electrification systems and the distribution network.” In addition, the E-LOBSTER solution supports the integration of regenerative braking energy, or recovery and storage of the braking energy typically lost as heat due to friction, further enhancing the railway network’s energy efficiency. Finally, the team developed an integrated distribution losses monitoring and simulation tool as well as a complex railway to grid (R+G) management system for real-time energy flow management between rail, grid and storage.
Sharing energy multiplies the benefits
“The E-LOBSTER R+G management system provides a unique platform for real-time monitoring and control of system operations, on-site or remotely. It can automatically and autonomously react to dynamic network changes, maximising local RES production through self-consumption, allowing braking energy recovery and minimising distribution losses and costs,” explains Loriga. It can also be used to investigate optimal charging/discharging strategies for EVs at railway stations or urban parking lots. In light of Europe’s ‘Fit for 55’ deal to end the sale of CO2-emitting cars by 2035, the ability to connect to EV charging infrastructures could unlock significant revenue generation opportunities for transport network operators investing in the system.
On track to increase the technology readiness level towards commercialisation
E-LOBSTER faced a continuously evolving policy and regulatory framework requiring considerable time handling the authorisation processes, but it was all more than worth it in the end. Loriga explains: “Without doubt, the most exciting thing was the opportunity to install such a complex system in a substation of the Madrid metro and test it under real conditions! The E-LOBSTER system made it possible to exploit the excess braking energy that would otherwise have been wasted.” The E-LOBSTER consortium has provided replication guidelines to support system deployment in other electric mass transit scenarios, and a roadmap towards demonstrating a real system in a fully operational environment. Shared power distribution and light railway networks are coming down the track.
Keywords
E-LOBSTER, energy, railway, grid, braking energy, EV, RES, energy storage, electric vehicles, soft open point
