A rapid transition to a new, resilient and entirely clean energy system is now possible, thanks to Elestor’s large-scale hydrogen-iron flow battery that can store (renewable) energy for long periods of time.
Elestor believes a clean and sustainable energy system, one that is robust, self-reliant and delivers energy security and independence, will soon be at the very core of society.
Large-scale, long-duration and affordable electricity storage will be a cornerstone of such an energy system, in the form of bi-directional power plants that will replace current plants powered by coal, gas or oil.
The power of renewables coupled with electricity storage extends well beyond their ability to supply affordable electricity to households, transport and industry. Tomorrow’s inclusive energy system will also provide clean air in cities, stabilise global temperatures. It will therefore help reduce the damage caused by natural disasters, and deliver economic prosperity that will arise from the thousands of green jobs in the energy sector and in the many new industries it will support.
The energy transition will unify the interests of the planet, the people and businesses’ desire for profitability, and it will exemplify corporate and societal purpose, which presently means it will become an essential part of national and regional total defence systems in a world that faces increasingly turbulent geopolitical conditions.
Reducing electricity storage costs to the absolute minimum will aid the creation of a new, clean energy system.
Elestor will do this in partnership with other players in the renewable energy industry, with committed, long-term investors, and with policymakers at both local, national and international levels.
This energy system will be based on three pillars:
- One: Renewable energy generated by solar and wind.
- Two: Large-scale, low-cost, and long-duration energy storage that is robust and resilient, thus ensuring electricity is available without sun or wind.
- Three: Sophisticated micro-grid, electricity grid and hydrogen pipeline infrastructure that helps distribute clean electricity to those who need it, whenever they need it.
The fundamentals of Elestor’s hydrogen-iron flow battery
Elestor’s hydrogen-iron flow battery is constructed around an electrochemical cell, the cell stack, where chemical energy is provided by the chemical reaction between two active materials. This stack consists of a number of individual electrochemical cells, as shown above, connected in series. Each membrane in this stack is connected to the electrolyte circuit, an aqueous iron-based solution (FeSO4).
Conversely, each membrane is in contact with a hydrogen (H2) gas circuit. Both active materials circulate in a closed loop along their own respective side of the cell. The electrolyte (aqueous FeSO4 solution) and hydrogen (H2) circuits are separated by a proton-conductive membrane.
Working principle
Flow batteries were initially developed in the 1960s by the USA’s National Aeronautics and Space Administration, better known simply as NASA. But it wasn’t until the 1980s that their popularity picked up speed, after they were proven to last for more than 10,000 charge/discharge cycles.
Along with the continuously growing installed base of renewable energy systems, most notably solar and wind power, it has become obvious that the need to store large, indeed very large, quantities of electrical energy for longer periods of time is growing equally quickly.
Such energy storage is essential if we are to achieve a total transition from fossil fuels to renewable energy.
The term flow battery covers a family of storage systems where each one applies the same fundamental working principle, while using different combinations of active materials. The heart of a flow battery is a so-called electrochemical cell, which is a multi-layer assembly of an ion-selective membrane, catalyst layers and electrodes.
The choice of hydrogen and iron
Elestor is powered by a mission to build a storage system with the lowest possible cost per MWh. With this as our cornerstone criterion, that can only be met with inexpensive chemistries, our behind-the-scenes R&D wizards have explored a variety of chemistry combinations.
In theory, there are many different chemistries that could be used to design a flow battery, but to date, we have only come across two that could work in the real world.
One relies on hydrogen and bromine as active materials, and this solution remains great on paper, but we have concluded that there is another, even better, so-called redox coupling, namely hydrogen-iron, which is better suited to real-world applications and the present geopolitical environment.
