IEEE Consumer Electronics Magazine - November/December 2021 - 98

Special Section on Advances in Smart Cities
city as almost all activities depend on energy
(both electricity and gas) and energy consumption
levels for different services in the city area
are much higher than other areas, e.g., rural and
suburban areas. Though the energy system is a
critical component for a smart city, there have
been very little efforts for managing this system
from such perspectives. For this reason, these
smart cities need to have provisions for effectively
managing energy from renewable and sustainable
sources as solar, wind, and battery
energy storage systems.
A sustainable energy management system for
smart cities is proposed by O'Dwyer et al.2 based
on a multivector energy system, where electricity
and gas are considered as two types of
energy consumed by different services. However,
the energy management system has a very
little role to play as the costs associated with
this are low and it is supplied by some fixed suppliers,
where consumers do not have many
options while there are many options for customers
for the electricity system. Furthermore,
the effective utilization of renewable energy
sources (RESs) will make these cities more
sustainable.
Different facilities in a smart city are currently
integrating RESs in their premises to
reduce electricity bills and become self-sufficient
by producing their own electricity.3 However,
most of these RESs are not being effectively utilized,
e.g., residential households cannot fully
consume power generated by their rooftop solar
systems as the solar peak is off-peak for these
facilities and this also applies for other facilities.
This excess energy is currently fed back to the
grid at a rate (called feed-in tariff), which is
much lower than the utility tariff (the rate at
which customers pay).4 However, the energy
can be stored and used later using energy storage
systems (ESSs) for which prosumers need to
invest more and there are still possibilities of
having excess energy after fully charging their
batteries. Hence, existing frameworks do not
provide cost-effective solutions for utilizing
RESs.
The economic efficiency of electricity systems
can be improved by sharing energy among
different facilities within the smart cities.5,3 In
such cases, the major technical challenge is the
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dynamic interactions among different power
generation sources and consumption facilities,
i.e., prosumers and consumers. Furthermore,
the control action for these generation sources
need frequent adjustments based on the information
obtained from other facilities.6 For
energy sharing and trading in smart cities, a
communication infrastructure is essential as
these activities depend on some critical information
(e.g., energy shortage and excess) for different
facilities. There is no such an energy
management system or energy hub that considers
all these features for energy sharing and trading
in smart cities.
This article aims to design a smart energy
hub (SEH) for smart cities by considering the
opportunities for the P2P energy sharing and
trading with three comprehensive features: i)
generalized smart grid communication (SGC)
infrastructure, ii) nonlinear distributed control
scheme for robust power sharing, and iii) an
energy trading framework. The SGC framework
for the proposed SEH is developed to capture
information from different prosumers and
consumers in smart cities from existing smart
facilities using both direct and relay-aided
communication schemes. The nonlinear distributed
control scheme is employed by considering
all nonlinearities and dynamics of
different power generation sources while
using information of neighboring generators.
Finally, an energy trading framework is developed
using the concept of a noncooperative
game in order to maximize economic benefits
of all parties participating in energy sharing
and a brief overview highlighting the implementation
as well as results based on a case
study is presented to demonstrate the feasibility
of the proposed SEH.
AN OVERVIEW OF ENERGY
SYSTEMS IN SMART CITIES
AND ARCHITECTURE OF
THE PROPOSED SEH
The key services, from the view point of the
power generation and consumption, within a
smart city is shown in Figure 1. There are lots of
small industries located near the city center,
which significantly contribute to the economy.
IEEE Consumer Electronics Magazine
IEEE Consumer Electronics Magazine - November/December 2021

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