Energy management in commercial building microgrids

Abstract

Energy systems face problems such as increasing energy cost, greenhouse (GHG) emissions, and network load deviations. A wide range of load variations may cause network instability. Large commercial buildings with a heavy load, treated as microgrids (μGs), may contribute meaningfully to demand response and network stability. Therefore, a strategy for optimal energy consumption and bidirectional power trade between the building and the utility grid is required for this class of customers. The objective of this paper is to develop a linear bi-level macro energy hub (MEH) control for a group of large commercial building μGs, to minimize the network load deviation, while satisfying the customer specified total μG energy cost and the GHG emission constraints. The resulting constrained optimization problem is mapped in a flower pollination algorithm environment under deterministic and uncertain conditions such as the random presence of solar irradiance and electric and natural gas networks. The μG considers the solar photovoltaic panel, internal combustion engine, fuel cell, microturbine, and electric vehicle lot and battery. Using the results obtained under deterministic conditions, customer-utility relationship is developed by applying the multi-linear regression analysis technique, between the network load deviation, operation and maintenance cost of distributed generators, μG's spinning reserve value, and total μG energy cost. Analysis proves that under an MEH, customer-utility interest is non-linearly related. Building owned micro energy hub control reduces the energy cost and the GHG emissions; however, the load deviation inflates and vice versa for utility owned MEH control. To address this nonlinearity, biogas is integrated with the MEH, using a method termed as integrated demand response (IDR), which successfully brings the energy cost down at a low load deviation. The results show that if uncertainties are not severe, the IDR alone will be adequate to bring the cost down for simultaneous achievement of end-to-end stakes. However, if the cost is high, due to adverse conditions, in addition to the IDR, the proposed load curtailment scheme is applied. Simulations demonstrate that the cost, GHG emission, and load deviation drop by 22.448%, 11.716%, and 36.410%, respectively, for biogas integrated MEH compared to building owned micro EH control.