Research Article
Flexibility Pricing of Grid-Connected Energy Hubs in the
Presence of Uncertain Energy Resources
Mousa Hamrahi , Mehrdad Mallaki , Naghi Moaddabi Pirkolachahi ,
and Najme Cheraghi Shirazi
Electrical Engineering Department, Islamic Azad University, Bushehr Branch, Bushehr, Iran
Correspondence should be addressed to Mehrdad Mallaki; mallaki@aut.ac.ir
Received 16 October 2022; Revised 18 December 2022; Accepted 12 April 2023; Published 24 May 2023
Academic Editor: Luis M. Fernández-Ramírez
Copyright © 2023 Mousa Hamrahi et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
The paper expresses the problem of flexibility pricing in energy hubs (EHs) that are in connection with electricity, heat, and gas
networks considering of uncertain energy generation sources. Scheme includes a bilevel formulation. Its upper-level states for
modeling of the flexibility services are provided by various resources within the EH. The problem considers maximization of
the expected profit of these resources in the flexibility market. The problem constraints include the flexibility model of flexible
resources such as storage devices, responsive loads, and controllable distributed generations (DGs). The flexibility model of
resources relies on their active and heat power. The lower-level problem calculates energy and flexibility prices and formulates
the flexible operation of energy resources considering EHs. Here, constraints include optimal power flow equations in the
energy networks; operation model of EHs with power sources, storage devices, and different responsive loads; and flexibility
limits of EHs. Also, a linear approximation model is adopted in the suggested design using conventional linearization
techniques. Next, the Karush–Kuhn–Tucker (KKT) method is used to derive a single-level model for the problem. The scheme
adopts scenario-based stochastic programming (SBSP) so that uncertainties of renewable power, energy price, load, and energy
consumption of mobile storage devices are properly modeled. Finally, the results validate the suggested design’s potential in
modifying and enhancing the operation, flexibility, and economic situation of energy networks and EHs.
1. Introduction
1.1. Motivation. Demand response programs (DRPs), energy
storage systems (ESSs), and distributed generations (DGs)
are extensively utilized in the power network, specifically
in distribution systems, hoping for decrease the amount of
pollutant emission [1]. This is in accordance with the deci-
sion complexity of the distribution system operator (DSO),
because the volume of information in the distribution sys-
tem will be significant. Thus, the smart grid concept recom-
mends the use of aggregator frames like energy hub (EH) to
coordinate the operation of the abovementioned elements in
the power system [2]. The EH considers simultaneous man-
agement of several types of energy so that it can improve
total energy efficiency [3]. Moreover, due to the low opera-
tion cost of renewable energy sources (RESs), EH possibly
include several RES units. However, the prediction of RES
generation power is uncertain as it depends on condition
like wind speed and irradiation. Since the prediction of a
parameter is always exposed to error, it is expected that the
parameter has an uncertain status [1]. Therefore, the pres-
ence of RESs in the EH makes the real-time (RT) and day-
ahead (DA) scheduling results different, and this might lead
to imbalance in network operation and the reduced flexibil-
ity of the EH in the electricity section. Flexibility as described
in [4] is the change in generation injection and/or consump-
tion paths due to an external price of an activation signal so
that a specific service is provided across the system. In other
words, while the RT and DA scheduling results of a system
differ in the presence of RESs, it is expected that the
Hindawi
International Journal of Energy Research
Volume 2023, Article ID 6798904, 21 pages
https://doi.org/10.1155/2023/6798904