The overall aim of this project is the investigation into redox flow batteries coupled to renewable energy sources (RES) and integrated as part of the electrical power system network and grid-level systems.

Our research is focussing on methods to raise flow-battery electrolye electrical density to deliver deep-capacity battery units with rapid transient responses (<1 second) to support network (>11 kV) and grid-level (>100 kV) energy storage and fast-response solutions.
The investigation will focus on testing an array of electrolytes including ionic liquids in order to improve the current flow battery energy densities between 20-50% and will benchmark their performance comparing the findings with standard commercial available redox flow technologies.

The technical research ambition and outcomes emerging from the project will directly impact on market modelling and energy trading studies in collaboration with project partners. Additional outcomes will contribute to the development of policies which govern All-Ireland national energy planning and future strategies, and influence DS3 engineering practice, recommendations and grid-code standards for integration of grid-level storage for 2020 and beyond.

This project will develop a new portfolio of research to give Ireland a competitive edge, both nationally and internationally for large-scale energy storage solutions using redox flow systems.

Ireland has fluctuating energy dynamics as a consequence of being an island with a comparatively small-scale power system that provides an excellent testbed for evaluation of energy storage solutions. Although Ireland has historically evolved into two regions separated by a geographical border, with different governmental and political dispensations, the approach proposed in this project recognises, acknowledges and affirms a one-island and holistic vision for electrical energy generation, consumption and storage to meet current requirements and to offer technologies for the strategic and diverse priorities of future electrical networks and grids.

The research is focussed on the development and optimisation of vanadium based electrolytes to improve energy and power density for a 1 kW lab scale redox flow battery system. The main starting point is on the investigation into innovative formulations that will maximise the availability of the vanadium ions in their coupling across the membrane in order to ensure maximum regeneration potential and energy density in the vanadium system. QUB will make use of its vast experience in the design and synthesis of electrolytes based on ionic liquid technology. These ionic liquids are non-volatile and will significantly reduce the flammability of the electrolytes and decrease the environmental impact. Importantly, by applying our vast expertise in the dissolution of metal salts and oxides in ionic liquids to the vanadium electrolytes, we will be able to dissolve significantly higher concentrations in these and hence improve the power densities and capacities of the VRF.

In parallel with the ongoing tests and evaluation studies on the 1 kW lab system, a 125 kW commercial redox flow battery unit will be tested onsite at Bombardier.

This practical site testing will provide significant benefits for proof of concept evaluation of full battery energy storage system (BESS) integration, demand-side management and participation assessment and investigation of technical applications, including peak-energy shaving and control of smart grid stability. The testing will also allow for fast-responses to system disturbances (rate-of change of frequency, ROCOF events) and future potential for development of market-trading parameters including price signals and tariffs.

Within this project, we have the unique opportunity to improve and integrate redox flow batteries all the way through from the electrolyte development, scale-up, testing in a lab scale and a 1 kW unit to the integration of a 125 kW unit on site of an intense energy consumer (Bombardier) with a combination of regenerative energy sources on site.

The proposed BESS project and deliverable solution will represent a clear milestone in storage innovation and open a path for progressive evaluation of future services to meet the needs of grid growth beyond 2020. The approach taken will make the electrolytes ‘greener’, less reliant on concentrated acids or volatile solvent additives with at the same time higher power density and an improved long-term stability.