Acid/base flow battery environmental and economic performance based on its potential service to renewables support

An innovative technology, called Acid Base Flow Battery (AB-FB), has been developed to overcome the intermittent supply of wind and solar electricity generation. It stores electrical energy using pH and salinity differences in the water and compared with other battery technologies, such as Vanadium Redox Flow Battery (VRFB), the new system is expected to be safer, more sustainable and to become a cost competitive option. To provide a deeper knowledge of the new system potentials, in this research, Life Cycle studies under cradle to grave approach have been carried out to assess the environmental and economic performance of 1 MW/6 MWh AB-FB system. Furthermore, 1 MW/6 MWh VRFB has been considered as the reference case. According to the comparative analysis, the AB-FB system exhibited the best environmental and economic performance, placing the AB-FB system as the most sustainable technology. In terms of environmental impacts related to the three process stages, the AB-FB system operation stage yielded the most relevant environmental burden, mostly attributed to energy losses due to the system efficiency. Manufacturing of the AB-FB system was the second stage with the more significant quote to the total environmental burden. Particularly, impacts were related to the power subsystem components being steel, copper, polyethylene and polyvinylchloride identified as the key materials responsible of this tendency. In contrast, the VRFB manufacturing was the most relevant process stage in terms of environmental implications. The energy subsystem was responsible for this tendency due to the vanadium-based electrolyte production related impacts. This component of the VRFB system was also its main constrains in terms of costs. The VRFB investment cost (339 €/kWh) was almost twice the AB-FB one (184 €/kWh), mostly affected by the VRFB electrolyte cost production.