Redox batteries to improve the integration of energy from renewable sources

Date 09-07-2015 IK4-TEKNIKER

In collaboration with the company ZIGOR, IK4-TEKNIKER is developing redox flow batteries that store energy by means of a chemical process between two separate liquid electrolytes. This new generation of efficient batteries with a long useful service life offers a solution for accumulating the energy produced by means of renewable sources, one of the big challenges facing the field of energy storage. 

The efficient integration of renewables, which in general are unmanageable within the electricity system, involves the incorporation of a technology that will allow the surplus that these sources are capable of generating to be stored, depending on the resource available (wind, sun, waves, etc.) If the power being demanded by the electricity system is lower than this renewable generation capacity, no storage takes place, and the surplus energy is lost.

Redox flow batteries have become a very competitive technology for the large-scale storage of energy which the renewables market is calling for. They offer flexibility with respect to power and energy needs in an independent way, depending on the capacity for renewable generation, and provide a useful service life in terms of the number of cycles, which exceeds that of other battery technologies, and this means their application is particularly suited to the integration of renewables.

In-house technology

IK4-TEKNIKER and the company ZIGOR are developing a first generation of redox flow batteries using medium-power, in-house technology; they can be used not only in the integration of renewables but also in the distributed generation of energy.

The two organisations are seeking to improve the design of the flow battery;

  • Optimization of the operating strategies to maximise efficiency and cost per kWh;
  • Design and development of a manufacturing process (in particular for critical components like frames), so that its assembly can guarantee the water-tight integrity of the unit and facilitate its construction as a modular concept, which should also be straightforward to maintain;
  • Development and integration of a flow battery with power electronics and control and ancillary elements that will enable a suitable energy module to be configured so that it can be applied in the integration of distributed energy;
  • And finally, the construction and marketing of a modular flow battery for its power scaling in such a way that it will be more simple to put on the market.

As Maddi Sánchez, head of this project at IK4-TEKNIKER, asserted, “redox flow batteries offer a solution with the necessary potential to store energy from renewable sources efficiently. This technology offers a virtually unlimited service lifetime in terms of number of cycles and a greater depth of discharge, and our systems stand out for the flexibility of their design; this means they can be adapted to applications demanding high power as well as a high capacity to store electricity. These qualities,” she highlighted, “make them a suitable candidate for responding to the demand of the renewables market”.