I-012

Pekka Peljo

pekka.peljo@utu.fi

Aalto University, Finland

Flow battery based technologies for energy storage in solids and for hydrogen and chemicals production

Volatility of the electricity cost due to increased share of intermittent renewable energy production in the grid offers opportunities for flexible technologies able to both store the electricity as well as produce hydrogen and chemicals. Such technologies can be developed as simple add-on units to flow batteries, for example a packed bed reactor filed with catalyst to realize hydrogen generation by chemical discharge of the flow battery electrolyte. As investment and operation costs of such add-on units is low, lower efficiency in comparison with electrolyzers is acceptable for a process that is only utilized when electricity is inexpensive.

We will describe our work to develop add-on units for flow batteries that allow electricity storage in solid redox active materials, as well as combined hydrogen and chemicals production developed in our DualFlow EU-project. In the first concept the redox active solids such as Prussian Blue are introduced into a packed bed as extruded beads, and undergo chemical oxidation or reduction with the flow battery electrolyte to store electricity with much higher volumetric capacity. In the second concept the charged electrolytes of the flow battery have sufficient driving force to spontaneously generate hydrogen in the presence of catalyst, as well as perform oxidation reactions for synthesis of chemicals in alkaline conditions.