Energy Storage Planning for Rural Microgrid with Agricultural Production in Cold Region

The paper develops a bi-level optimisation model to determine the best capacity of a battery energy storage system (BESS) supporting an islanded rural microgrid for agricultural production. In the lower level, a microgrid scheduling model is proposed to coordinate wind-solar complementary outputs with BESS charge/discharge to meet electricity loads for maintaining vegetable greenhouse temperature over each day subject to the state of charge limits of the BESS. The resulting loss of energy expectation (LOEE) caused by insufficient renewable power outputs and limited BESS capacity over a year is estimated and then combined with the annuitised capital costs of BESS in the upper level to form a weighted cost function. Then, a particle swarm optimisation algorithm is employed to optimise the BESS capacities in terms of power and energy for minimisation of the cost function. The proposed bi-level optimisation model is tested based on a practical rural microgrid in Northeast China. The BESS capacity optimisation results are compared between the use of different penalty factors assigned to LOEE and discussed alongside effects of LOEE values on BESS sizing.