Reversible solid oxide cell technology as a power storing
solution for renewable energy (Italy)

Elcogen is developing ground breaking fuel cell technology to demonstrate how solid oxide cells can be used as power storing solution for renewable energy.

We have successfully fulfilled the goal to develop solid oxide fuel cells for reversible mode. Reversible Solid Oxide Cell (rSOC) technology is able to operate either in electrolysis mode (SOEC) to store excess electricity to produce H2, or in fuel cell mode (SOFC) when energy needs exceed local production, to produce electricity and heat again from H2 or any other fuel locally available.

The reversible fuel cell development is a part of EU funded project REFLEX. The project coordinates the development of reversible SOFC/SOEC system, which will be integrated in a “Smart Energy Hub coupled with batteries to solar and mini-hydro renewable sources to provide both electricity and heat to the nearby technology park in Italy. The system will use Elcogen’s market-leading solid oxide fuel cell technology.

REFLEX is funded from the Fuel Cells and Hydrogen 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No 779577).

The uniqueness

The challenge of renewable energy

The Climate action (COP21), signed by numerous countries around the world, confirms that direction with a strong need of renewable energies increase. Solar PV (photovoltaic) and wind power will be the keys to meeting carbon emission goals. In some scenarios, up to 65% of EU power generation will be covered by solar photovoltaics (PV) as well as on- and offshore wind (Energy Agency in its 2016 report).

However, the issue of their intermittency with both seasonal as well as weekly and hourly weather variability and their low predictability must be solved. Resilient energy systems need to be developed and deployed with a central aspect being the energy storage.

rSOC could be the solution

Indeed, buildings and eco-districts are increasingly becoming energy producers, with growing amounts of PV panels installed. Optimizing the self-consumption of this locally produced energy becomes a priority issue for the energy transition in order to avoid putting strain on the transmission and distribution network. Storing this energy to restore it locally, while having the option to produce locally with the same equipment combined heat and power (potentially also from methane or bio-methane and not only H2) thanks to a rSOC based system, will ensure that the electricity supply matches demand at all times.

The REFLEX project will demonstrate, in-field, the high power-to-power  round-trip efficiency of this technology (as compared to other H2 based solutions) and its flexibility and durability in dynamic operation (power transient and switch between electrolysis and fuel cell mode).

The Goals

Reversibility of SOEC/SOFC is seen as a strong disruptive innovation, that can allow to dramatically reduce the CAPEX in a power-to-power chain, as only one asset is needed, instead of two in a standard power-to-power chain (electrolyser and fuel cell systems), which in addition operates 100% of the time, which maximise the return on investment..

Elcogen goals

  • To optimize cells , which are integrated into 3rd party stacks for operation at high fuel utilization (> 85%) in both SOEC and SOFC modes and at high current density (- 1.2 A/cm² in SOEC mode below 1.3 V at 700°C, 0.6 A/cm² above at 0.8V in SOFC mode) to minimize the number of cells and the size of the stack for a defined power in order to minimize the CAPEX
  • To exploit the intrinsic flexibility of cells and stacks, to allow power modulations while keeping safe thermal conditions within the stack (not too endothermic, not too exothermic)
  • To implement it in a real site to provide electricity and heat to commercial buildings
  • To explore the electrolyze operational flexibility at the demonstration site (power modulation targeted between 50-100% in SOFC mode and 70-100% in electrolysis mode)
  • To operate the electrolyze system for 8000 hours on site with a degradation rate of less than 2% of the voltage per 1,000 h.

Key figures of Reflex project

  •  To develop an upscaled system of 15 kW SOFC and 80 kW in electrolysis mode to produce 16 Nm3/h of hydrogen, with the same efficiencies as previously obtained at small scale: > 80% HHV in SOEC mode, > 55% LHV in SOFC mode with CH4 fuel supply;

The consortium

The development of reversible SOFC/SOEC system is divided between nine organizations from six EU countries. Each organization has its own specific task to fulfill.


Reversible solid oxide fuel cells development

Elcogen is developing solid oxide cells (SOFC, SOEC) technology in cooperation with CEA and DTU.

Elcogen was selected given the company has developed the world’s most efficient solid oxide fuel cell (SOFC) technology, with the market’s highest electrochemical performance and lowest operating temperature. Elcogen designed its SOFCs to be manufactured at scale and produced from low-cost raw materials.

For REFLEX project, Elcogen optimized the reference SOFC cell in terms of microstructure, thicknesses of constituting layers, interfaces, in order to achieve high power densities and long durability in flexible mode.



Reversible solid oxide stack development

CEA (French Alternative Energies and Atomic Energy Commission) is a Research and Technology Organization (RTO). It aims to produce, integrate and transfer science and technology to help resolve the main EU challenges: low carbon energies, defense and security, information and healthcare technologies. CEA has more than 16,000 employees, filing more than 500 patents / year.

In REFLEX project, CEA is optimizing the stack to integrate Elcogen optimized cells and to operate in reversible mode.



Power Electronics

GPTech is a pioneer company in the development of power electronic devices which uses the state of the art technology to provide new solutions to the Renewable Energy Sector. GPTech’s experience in grid integration has made the company one of the most important suppliers of power electronics devices all over the world with presence in Europe, America, Asia and Africa.

In REFLEX project, GPTech and USE are taking care of power electronics development adapted for rSOC systems.


University of Seville

University of Seville is the third largest university in Spain. The Department of Electronic Engineering (DEE-US), is focused on the research activities of innovative electronic technologies in industrial applications: information technology and communications, microelectronics, industrial power electronics converters and hardware specific control.

Reversible system design and manufacturing

Sylfen develops a fully integrated energy-storage system based on r-SOC technology (reversible Solid-Oxide Cells).

In REFLEX project, SYLFEN is designing, engineering, manufacturing and installing on-site the demonstration rSOC based Smart Energy Hub.



System modelling

VTT Technical Research Centre of Finland is a non-profit government organization. VTT is the largest public applied research activity in Northern Europe with a staff of 2500.

In REFLEX project, VTT is supporting the system design by modelling tasks.


System field testing

Environment Park located in Turin Italy is an innovation accelerator for 70 companies that aim to expand their market with eco-efficient solutions. Energy savings, waste disposal, clean energy, new materials and assistance to fund raising are the keys to success that EnviPark offers companies and public administrations to revolutionize their modus operandi.

The REFLEX system will be installed at the ENVIPARK headquarter, to provide electricity and heat and maximize auto-consumption of local renewable energies mixture.



Techno-economical analysis

ENGIE is a French multinational utility company operating in the fields of electricity generation and distribution, natural gas, nuclear, renewable energy and Petroleum.

In REFLEX project, ENGIE is taking care of the techno-economic and market assessment.



The results so far for SOC cells


Developments and characterisations of reversible solid oxide  cells have started from January 2018 and will last until the end of 2020.

Standardized cell performance evaluation at open circuit voltage (OCV) and targeted operating conditions of various microstructure modifications, i.e. fuel electrodes, oxygen electrodes and barrier layer, have been conducted.

Currently we can state that Elcogen has developed solid oxide cells with reversable mode. Our cells can produce electricity from fuels like biogas, diesel, natural gas, ethanol, methanol, propane, wood gas and LPG (SOFC mode). And to store excess electricity by producing hydrogen (electrolysis, SOEC mode) within the same cells. The developments of reversible cells continue until 2020.

The REFLEX project –  FCH2 JU grant agreement number 779577  Started: 01/01/2018 – Duration: 36 months


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Mr. Marek Roostar

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