India has a total electricity generation installed capacity of 416 gw in 2023, which generated 1.62 twh of energy in fy 2022-2023. india have ambitious targets to decarbonize all sectors by 2070. hence, india is pushing for installation of renewable energy sources for electricity generation. out of total installed capacity, renewable energy installations including solar, wind, and hydro constitutes of 179 gw as of july 2023. by 2030, india plans to increase renewable installations to 500 gw which will be 50% of cumulative power installations. the problem with renewable energy sources like solar and wind is that the on-demand electricity generation is not possible, due to their intermittent nature. this supply-demand gap leads to 15-20% of renewable energy curtailment in india, where the energy is not pumped to grid, essentially energy is wasted. this created excess burden on the coal fired power plants, where they reduce generation during the day time when solar generation is high, and have to increase power generation to peak in night time when solar generation is zero. this burden on grid replicates a ‘duck curve’ which represents the need for sudden surge in power generation by coal power plants within 2-3 hours to meet energy demand, specifically in the evening. when the share of renewable energy generation increases to >20% in next few years, the burden on grid will increase significantly and experts fear a grid instability or complete power black-out. as the share of renewable energy generation increase, the storage of excess energy generated during day time and using it during night time when generation is minimum is the only solution to stabilize grid and achieve energy security. india’s energy storage market is currently at usd 3.1 billion and is projected to reach usd 5.27 billion by 2028 with a cagr of 11.2%. by 2030, india would need 41.65 gw/208.25 gwh of battery energy storage systems to meet its electricity demand. but, currently india has only 37 mwh of installed energy storage capacity. on the other hand, except lithium battery technology, there is no other technology which can store electricity in gwh scale. but, lithium battery technology is not indigenous and raw materials are not available in india, due to which the storage costs are exorbitantly high. currently, the levelised cost of electricity (lcoe) from battery energy storage is 5.5 – 6.5 rupees per unit. also lithium-ion batteries have high fire hazard, rising severe safety concerns. this indicates the desperate need for developing an indigenous battery technology which can store energy in gwh scale with extreme safety and at very low lcoe of <1 rupee per unit. we have indigenously developed zinc-air battery as an alternative battery technology for large-scale, long-duration energy storage. the charging-discharging processes are decoupled and operated simultaneously. a zinc charging station was built to recycle discharged zinc oxide from battery using renewable energy, and stored safely as compact zinc plates for more than a year with negligible self-discharge. this enabled excess renewable energy storage as and when it is generated. a 200 ah mechanically refuellable zinc-air single cell was designed and fabricated with our proprietary in-house developed gas diffusion electrodes. the recycled compact zinc plates can be inserted in the battery pack for discharge upon energy demand. the discharge tests confirmed a gravimetric and volumetric energy density of 300 wh/kg and 600 wh/l respectively at module level. we also have demonstrated ~2 minutes refueling time in a 1.2 kwh module having six cells. the 30 kwh battery pack and corresponding recharging station were fabricated at ~70 $/kwh. the operation of this pack with aqueous electrolyte have demonstrated its inherently safe nature.