BEST panel clears 220 MW solar-battery power deal, eyes Rs 100 crore annual savings. The BEST committee on Thursday gave its nod for the power sale agreement with Solar Energy Corporation of India (SECI) for procuring 220 MW of solar power integrated with Battery Energy Storage Systems (BESS). This will shield the undertaking from expensive power purchased from the market during peak hours and will have a Rs 2.86 per unit cost for solar power.