Optimal allocation of hybrid energy storage for microgrids based on multi-attribute utility theory

To satisfy the requirements of high energy density, high power density, quick response and long lifespan for energy storage systems (ESSs), hybrid energy storage systems (HESSs) have been investigated for their complementary characteristics of ‘high energy density components’ and ‘high power density components’. To optimize HESS combinations, related indices such as annual cost, fluctuation smoothing ability as well as safety and environmental impact have to be evaluated. The multi-attribute utility method investigated in this paper is aimed to draw an overall conclusion for HESS allocation optimization in microgrid. Building on multi-attribute utility theory, this method has significant advantages in solving the incommensurability and contradiction among multiple attributes. Instead of determining the weights of various attributes subjectively, when adopting the multi-attribute utility method, the characteristics of attributes and the relation among them can be investigated objectively. Also, the proper utility function and merging rules are identified to achieve the aggregate utility which can reflect comprehensive qualities of HESSs.