Double-layer Firefly Algorithm for Simultaneous Optimal Sizing and Operation of Energy Hubs

For economical and efficient use of local multi-carrier energy systems, energy hubs (EHs) were introduced as the best solution. EHs as one type of distributed generation have made the use of multi-carrier energy systems attractive with better energy conservation. To achieve the economic and environmental objectives of the EH, the sizes of its components need to be optimally selected. In addition, to check the incentive of the EH, it must be studied under operation. For this reason, the economic dispatch of the EH is to be carried out. However, the two objectives of optimal design and optimal dispatch have been previously addressed as two separate problems one step after another. In this paper, a double-layer firefly based optimization algorithm is proposed to both optimally size and dispatch the EH components, simultaneously. The two problems are combined in one multi-objective optimization problem. The objectives are to minimize the total capital and operational cost of the EH, minimize the system emission, and maximize the cost of exported energy to the network. The proposed algorithm is effectively applied to a commercial facility (hospital) as a case study.