C. Calvillo, A. Sánchez, J. Villar. Energy management and planning in smart cities. Renewable & Sustainable
Energy Reviews. vol. 55, pp. 273-287, March 2016. JCR: 8.050 (2016)
1
Energy Management and Planning in Smart Cities
C. F. Calvillo
1
*, A. Sánchez-Miralles
1
, J. Villar
1
1
Institute for Research in Technology (IIT)
ICAI School of Engineering, Comillas Pontifical University
Santa Cruz de Marcenado 26, 28015, Madrid, Spain
* Corresponding author
Email addresses: christian.calvillo@iit.comillas.edu (C.F. Calvillo), alvaro@comillas.edu
(A. Sánchez-Miralles), jose.villar@iit.comillas.edu (J. Villar)
Abstract
A smart city is a sustainable and efficient urban centre that provides a high quality of life to
its inhabitants through optimal management of its resources. Energy management is one of
the most demanding issues within such urban centres owing to the complexity of the energy
systems and their vital role. Therefore, significant attention and effort need to be dedicated
to this problem. Modelling and simulation are the major tools commonly used to assess the
technological and policy impacts of smart solutions, as well as to plan the best ways of
shifting from current cities to smarter ones.
This paper reviews energy-related work on planning and operation models within the smart
city by classifying their scope into five main intervention areas: generation, storage,
infrastructure, facilities, and transport. More-complex urban energy models integrating more
than one intervention area are also reviewed, outlining their advantages and limitations,
existing trends and challenges, and some relevant applications. Lastly, a methodology for
developing an improved energy model in the smart-city context is proposed, along with some
additional final recommendations.
C. Calvillo, A. Sánchez, J. Villar. Energy management and planning in smart cities. Renewable & Sustainable
Energy Reviews. vol. 55, pp. 273-287, March 2016. JCR: 8.050 (2016)
2
Keywords: Smart City; Renewable Sources; Energy Storage; Smart Grid; Distributed Energy
Resources; Transport Systems.
1. Introduction
The smart city is a relatively new concept that has been defined by many authors and
institutions and used by many more. In a very simple way, the smart city is intended to deal
with or mitigate, through the highest efficiency and resource optimization, the problems
generated by rapid urbanization and population growth, such as energy supply, waste
management, and mobility. Many classifications of smart-city intervention areas can be
found in the literature, as in [1] and [2]. A drawback of these classifications is that they
categorize energy mainly based on the smart grid, overlooking other relevant energy
elements, like transport and facilities.
Cities’ energy requirements are complex and abundant. In consequence, modern cities should
improve present systems and implement new solutions in a coordinated way and through an
optimal approach, by profiting from the synergies among all these energy solutions. The
intermittency of renewable sources, the increasing demand, and the necessity of energy-
efficient transport systems, among other things, represent important energy challenges that
are better addressed as a whole [3] rather than separately, as is usually the case.
Simulation models have been developed to assist stakeholders in understanding urban
dynamics and in evaluating the impact of energy-policy alternatives. However, very often
these efforts address energy areas separately, lacking the “full picture” and, therefore,
producing suboptimal solutions. A comprehensive smart-city model that includes all energy-
related activities while keeping the size and complexity of the model manageable is highly
desirable in order to successfully meet the increasing energy needs of present and future
cities.
This work proposes five main energy-related activities that have been called intervention
areas (see Fig. 1): generation, storage, infrastructure, facilities, and transport (mobility). All
C. Calvillo, A. Sánchez, J. Villar. Energy management and planning in smart cities. Renewable & Sustainable
Energy Reviews. vol. 55, pp. 273-287, March 2016. JCR: 8.050 (2016)
3
these areas are related to each other but contribute to the energy system in different ways:
generation provides energy, while storage helps in securing its availability; infrastructure
involves the distribution of energy and user interfaces; facilities and transport are the main
final consumers of energy, as they need it to operate. Energy systems’ implementations are
supported by three main layers: intelligence (control/management), communication, and
hardware (physical elements and devices). Hence, multidisciplinary solutions are expected.
This research mainly focuses on the hardware and intelligence layers.
This paper has two main objectives. The first is to develop insight into the complexity of the
energy-related activities in a smart-city context by reviewing advances and trends and by
analysing the synergies among different intervention areas. Moreover, some of the most
typical applications found in the literature for the various energy areas, as well as operation
and planning tools, are reviewed. The second objective is to assist stakeholders and
policymakers in the design of energy solutions for smart cities by providing strategies for the
effective modelling and management of energy systems and by reviewing existing projects
and software tools. These strategies include the most relevant elements and common sources
of information required for their mathematical modelling.
This paper comprises two parts: the first (sections 2–6) presents a review of the research
developed in the proposed intervention areas involving energy in smart cities. Section 2
addresses advances in energy generation in a smart-city context, section 3 reviews several
storage systems and their applications, section 4 analyses the actual state of the technology
and perspectives in the area of infrastructure, section 5 presents energy-related technologies
and systems implemented in facilities, and section 6 analyses the advances in energy
consumption of transport systems. The second part comprises section 7; it reviews current
energy-modelling approaches for smart cities and proposes a methodology for energy-system
planning and operation. Finally, concluding remarks and recommendations can be found in
section 8.
C. Calvillo, A. Sánchez, J. Villar. Energy management and planning in smart cities. Renewable & Sustainable
Energy Reviews. vol. 55, pp. 273-287, March 2016. JCR: 8.050 (2016)
4
2. Generation
From an energy-generation perspective, two main research lines are attracting the most
attention. On one hand, renewable-energy sources entail a mid- to long-term investment for
energy self-sufficiency without compromising future generations [3], although other non-
renewable sources, such as combined heat and power (CHP) with natural gas and biomass
generation (considering that these alternatives are less polluting than conventional generation
[22], [101]), can also be a suitable short-term alternative for reducing emissions and meeting
the energy demand [4]. On the other hand, distributed generation (DG) is gaining interest as
a tool to increase efficiency and to support grid reliability and resiliency [5]. The benefits
and requirements of DG have been studied widely [6], [8].
It is important to note that the smart city should gradually migrate to a full renewable-energy
scheme, a goal that can be facilitated by DG. Hence, although conventional generation will
still be present in smart cities in the short to medium term, it is not addressed in this section.
2.1. Generation technology review
Different generation solutions can be successfully implemented in a smart city; Table 1
summarizes important characteristics of the studied technologies.
C. Calvillo, A. Sánchez, J. Villar. Energy management and planning in smart cities. Renewable & Sustainable
Energy Reviews. vol. 55, pp. 273-287, March 2016. JCR: 8.050 (2016)
5
Photovoltaic (PV) panels convert solar energy into direct-current electricity using
semiconducting materials. They have been extensively studied and highly preferred in small-
scale generation, mainly owing to the significant cost reduction in recent years resulting from
the competitive values of the levelized cost of energy (LCOE) [33], [34]
Thermal collectors (TCs) collect heat by absorbing sunlight. They have been proved a
reliable source for heating water or any other heat-transfer fluid for any kind of application
[11]. TCs have affordable prices on a small scale, and can be implemented as concentrated
solar-power (CSP) plants for utility-scale electricity generation [12]; they are normally used
with some sort of thermal generation. This kind of generation has a competitive LCOE;
nevertheless, it is not suitable in cities. In addition, photovoltaic-thermal collectors (PV/T)
work as regular PV cells but also deliver thermal energy in order to heat water or other fluids.
PV/Ts have high efficiency, but there are few commercial modules, and these exist only in
small scale [13].
Wind turbines (WT) are used to extract power from an air flow to produce mechanical or
electrical power. This is a mature technology with a wide variety in system sizes, producing
cheap energy at the utility scale. However, such technology is expensive on a small scale,
Table
1
.
Comparison of most common distributed energy sources
Generator
Generated Power
Dispatchable
Efficiency
Common
application†
electric
thermal
Solar PV
Yes
No
No
L
ow
(<30%)
Hh, B
Solar TC
No
Yes
No
M
oderate
(<=60%)
Hh, B,
Solar CSP
Yes*
Yes
Yes
M
oderate
(<=60%)
(D)t/(D, P)e
Solar PV/T
Yes
Yes
No
M
oderate
(<=60%)
Hh, B, D
Windpower
Yes
No
No
M
oderate
(<=60%)
D, P
Poly
-
gen.
Yes
Yes
Yes
High (>60%)
B, D
Biomass
Yes
Yes
Yes
M
oderate
(<=60%)
(Hh, B, D)t/
(D, P)e
Geothermal
Yes*
Yes
Yes
High (>60%)
(Hh, B, D)t/
(D, P)e
*Indirect production.
† Hh: Household, B: Building, D: District, P: Power plant.
