The European Union’s ambitious pivot towards climate neutrality is driving a seismic shift in the continent’s energy landscape, with renewable energy sources like wind and solar photovoltaic (PV) increasingly taking center stage. This transition, however, presents a formidable challenge: balancing electricity consumption and production in a grid designed for a different era. Enter the EU-funded HiHELIOS project, a pioneering initiative that aims to revolutionize energy storage and grid flexibility.
HiHELIOS is tackling a critical gap in current Battery Energy Storage Systems (BESS). Today’s technologies often force a compromise between power and energy capacity. No single chemistry excels at delivering both high power for grid stability and high energy for long-duration storage. HiHELIOS is set to change that with its innovative Hybrid Energy Storage System (HESS), a single, integrated solution that combines the best of both storage technologies.
The project’s core innovation lies in its hybrid design, which merges two distinct types of energy storage technologies. For long-duration needs, HiHELIOS leverages second-life Nickel Manganese Cobalt (NMC) battery modules repurposed from electric vehicles (EVs). This provides cost-effective, high-capacity storage while extending the lifespan of EV batteries and reducing their environmental impact. For rapid bursts of power, the system integrates either Lithium Iron Phosphate (LFP) batteries or supercapacitors, which react in milliseconds to ensure grid stability.
This modular approach allows each HiHELIOS system to be precisely tailored to the application’s needs, optimizing performance, lifetime, and cost-effectiveness far beyond conventional single-chemistry systems. The project targets a lifespan of over 5,000 cycles and a levelised cost of storage (LCOS) below 0.05 €/kWh by 2030.
To ensure the high-energy and high-power systems work in synergy, HiHELIOS is developing an advanced, multi-layered control architecture. This hierarchical system consists of three main layers: the Energy Management System (EMS), the Power Management System (PMS), and the Battery Management System (BMS). The EMS operates in the cloud, using advanced forecasting to plan the optimal charging and discharging schedule. The PMS, located on-site, translates strategic commands into real-time actions. The BMS monitors the health, temperature, and state of charge of every battery cell, ensuring they operate safely.
This intelligent framework will be enhanced by advanced battery models and ‘digital twins’ for real-time diagnostics and predictive maintenance, further extending the system’s life.
To prove its versatility, HiHELIOS is deploying its HESS in four distinct use cases across Europe:
1. **EV fast-charging support in Norway**: At a fast-charging station to manage extreme power peaks caused by multiple EVs charging simultaneously, avoiding costly grid reinforcements, and storing excess local PV production.
2. **Smart EV charging and grid support in Belgium**: Retrofitting an existing battery system to optimize a local energy community management with EV charging, solar power integration, and flexibility services procurement to the building and the local grid.
3. **Weak and islanded grid support in Greece**: On the island of Tilos, two HESS demonstrators will be deployed. One will support a smart marina’s microgrid, enhancing reliability for EV charging and local loads, and avoiding congestion. The second HESS will be part of a municipal hybrid power station, providing critical stability services and increasing energy storage capabilities.
HiHELIOS is more than a research project; it is a direct pathway to commercialization. The primary goal is to deliver four fully operational demonstrators at Technology Readiness Level (TRL) 7. At the project’s conclusion, these systems will remain in service, providing long-term, real-world validation of their performance, reliability, and economic viability.
The project brings together 12 partners from six countries, ensuring a direct path from R&D to market application. As HiHELIOS project coordinator Dr. Ioannis Psarras states, “We are already building a concrete roadmap to achieve TRL 9 and prepare for industrial-scale deployment.”
HiHELIOS is actively seeking stakeholders, investors, and industrial partners to develop technical or commercial partnerships and help shape a resilient, sustainable, and competitive European energy future.
This project could significantly shape the development of the energy sector by demonstrating the viability of hybrid energy storage systems. If successful, it could accelerate the integration of renewable energy sources, enhance grid stability, and reduce the environmental impact of energy storage technologies. The project’s focus on second-life EV batteries and its modular, tailored approach could also drive innovation in battery recycling and repurposing, contributing to a more circular economy.
Moreover, the advanced control architecture and digital twin technology developed by HiHELIOS could set new standards for energy management systems, improving the efficiency and reliability of energy storage solutions. The project’s diverse use cases and international partnerships