Optimal energy management system for carbon-neutral microgrid integrating second-life batteries and crypto mining devices

Carbon-neutral power generation is the need of the hour and the sustainable path to the same is provided by microgrids (MGs). The study presents a purely renewable-based carbon-neutral MG to power a campus (Asian Institute of Technology) where the excess energy is accounted by grid trades or for powering crypto mining devices (CMDs), whereas the deficit is balanced by the grid. To minimize the MG operational cost, an optimal energy management strategy is proposed that incorporates the flexibility of CMDs and second-life batteries (SLBs) by formulating a mixed integer linear program (MILP) optimized using the CPLEX solver. The analysis shows that the operational cost can be reduced significantly with the incorporation of CMDs and SLBs. By introducing battery capacity and Bitcoin (BTC) price as the sensitivity parameters, it is also identified that with the increase in BTC price, the required capacity of both the fresh and second-life Li-ion batteries reduce, significantly lowering the operational cost of the MG further. Finally, the comparative economic analysis of the MG with fresh and second-life Li-ion batteries demonstrates that the latter provides an economic and viable option stacked against the former.