RESEARCH ARTICLE Water’s Role in Smart Cities · RESEARCH ARTICLE Water’s Role in Smart Cities...
Transcript of RESEARCH ARTICLE Water’s Role in Smart Cities · RESEARCH ARTICLE Water’s Role in Smart Cities...
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RESEARCH ARTICLE
Water’s Role in Smart Cities
Teresa Zawerthal da Silveiraa, Helena M. Ramosb
aMaster student of Civil Engineering at Instituto Superior Técnico, Technical University of Lisbon, Lisbon, Portugal; bPhd. Professor in Civil
Engineering Department and CEHIDRO, Instituto Superior Técnico, Technical University of Lisbon, Lisbon, Portugal
Abstract: The water management in smart cities is an issue increasingly valued in the context of financial and environmental
sustainability of water supply systems. In addition to the non-return of the investment made in the acquisition, production and
distribution associated with the water losses, the supply systems also have a leading role in the management of the urban water
cycle, and must comply with this element as a feature increasingly scarce on the planet, thus their conservation is also a civic
responsibility. Currently there are increasingly technological innovations capable of making the management of smart water. In
this sense, the main objective of this dissertation was to disclose the technological breakthroughs associated with water use and
the innovations in methodology and monitoring of water losses in supply systems, as well as the benefits that these measures can
offer to the society of today and in the future as well. In addition, an analysis was carried out to the excellent results obtained by
Empresa Portuguesa das Águas Livres (EPAL), the public water Company of Lisbon, due to the implementation of measures for the
monitoring and water losses control in the distribution network associated with a smart water management. The measures
implemented by EPAL are a worldwide reference in smart water management, placing Lisbon at the level of one of the most
efficient cities in terms of non-revenue water. Finally, through the evaluation of the financial effort and savings obtained by EPAL
in the supply network, was estimated what would be the investment required in the monitoring and water losses control in Water
Company, in Porto city, in order to reduce the losses to get sustainable values until 2025.
Keywords: Smart cities; smart water management; smart water system; water supply system; district monitoring areas; water
losses.
1 INTRODUCTION
Since the 1970s, we have observed an increase of
environmental awareness, the evolution of technology and
communications, and the automated production leading to the
need to put environmental issues on the agenda. The report
prepared by the United Nations, entitled "Our Common
Future" emancipates the concept of sustainable development
as the basis for a global economic policy that must go towards
our current needs without compromising those of future
generations (Brundtland, 1987). The water industry has been
subject to changes and opinions with regard to the sustainable
management of urban water. There are many external factors,
including the impacts of climate change, drought, population
growth and its placing in urban centers, which lead to an
increase of the responsibility on providers of water services in
order to adopt more sustainable approaches to the
management of urban waters. The coverage of the costs, the
monitoring of the water without profit and meet the demand
of customers for the fairness in revenues are some of the main
challenges (Boyle et al., 2013).
As is referred to in the Annual Report of the Water and Waste
Sector in Portugal, there are many structural challenges on the
development of modern societies, from the water supply to the
population and economic activities, to the improvement of
urban wastewaters, as well as the management of municipal
waste.
The population growth results in an increase and a
concentration of water needs for various uses and the
consequent need of wastewater and waste management, in
increasingly large amounts. In this reality it is necessary the use
of advanced technologies and the adoption of more robust
management models, that are better suited to the population
demands (Baptista et al., 2009).
2 OVERVIEW OF THE WATER SECTOR
Over the past decades, with the growing water demand, the
risks of pollution and severe water stress in many parts of the
world have increased. The frequency and the intensity of water
crises have increased, with serious implications for public
health, environmental sustainability security in both food and
energy department, and economic development. Although the
central and irreplaceable roles that water plays in all the
dimensions of sustainable development have become
increasingly recognized, the management of water resources
and the provision of services related to the water continues to
be too low in the scale of public perceiving and government
priorities. As a result, the water is often a limiting factor, rather
than a facilitator of social welfare, economic development and
healthy ecosystems. The fact is that there is water available to
meet the growing needs of the world, but not without first
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dramatically change the way water is used, managed and
shared. The global water crisis is a reflection of governance,
much more than with the availability of the resources (WWAP,
2015).
In Figure 2.1 the estimated global hydric availability made by
the World Resource Institute, as reflected in annual flow of
each hydrological basin.
Figure 2.1 – World hydric Availability, (WRI, 2015).
This is not, however, to ensure the supply of water by any
means. Until the year 2000, humans had built approximately
45,000 large dams which, combined with the hundreds of
thousands of smaller structures, quadrupled the storage of
water for human consumption in just 40 years. However, it was
not examined or was able to predict the effects that, on a global
scale, the cumulative construction of dams uncoordinated,
deviations of irrigation and the impacts related to the
deforestation would have on the extension, availability and
quality of water. Today it has become clear that the human
activity started to affect the hydrology of the earth. Our
presence, our actions and its consequences have changed the
very composition of the atmosphere, the precipitation and the
places where the rain falls; the human behavior is affecting the
pattern of rain and snowfall (Sandford, 2012).
The uneven distribution of availability and demand, population
growth, climate change and water mismanagement aggravated
the situation of extreme water stress. The shortage of water is
not only a threat to human and economic development, but
perhaps the main reason for the political instability of the
future.
Figure 2.2 presents a global water stress assessment, exposing
the annual volume captured by municipalities, industries and
agriculture, as a percentage of the hydric availability. Thus, the
higher values indicate the locations that have a higher water
stress, with higher consumption in relation to the availability of
water, where it will be necessary to adopt a more sustainable
approach to water management.
Figure 2.2 – Global assessment of hydric stress, (WRI, 2015).
3 SMART WATER MANAGEMENT IN THE CITIES
3.1 CONTEXT
The smart water management has as objective the exploitation
of water, at regional level or at city level, on the basis of the
ideals of harmony, sustainability and self-sufficiency, through
the use of innovative technologies, such as the water recycling
among other technologies for water treatment, information
technology, monitoring and control technology and through
the implementation of the registration system of the water
cycle to work as a "water flow and information." (Tadokoro et
al., 2011).
3.2 THE CONCEPT OF SMART CITY
The concept of smart city is relatively recent, from the
technological innovations and also of the globalised world in
which we are currently placed in.
A smart city can be defined as the city in which it is performed
an investment in human and social capital, by encouraging the
use of Information and Communication Technology, ICT, as
enabler of sustainable economic growth, providing an
improvement in the quality of life of residents and floating, and
consequently, allow better management of natural resources
and energy. The smart cities will be those who are able to
reconcile the human flows through the new technologies,
mobility and sustainability.
However, it is important to recognize that the concept of smart
city is not limited only to technological advances, but aims to
promote the socioeconomic development. Social inclusion is a
fundamental characteristic of smart cities and all opportunities
for the economic development need to be coupled with
investments in social capital (Colldahl et al., 2013).
The definition of smart cities, by Giffinger et al. (2007), is based
on a Model of Smart City. This model is a system of
classification in which the smart cities can be evaluated and
developed through six distinct characteristics. The Model of
Smart City was developed as a classification tool to assess smart
cities communities of average size in the areas of economy,
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people, governance, mobility, the environment and lifestyle.
Through this model, a city can examine its current state, and in
turn, identify the areas that require further development in
order to meet the conditions necessary for a smart city.
3.3 SMART WATER SYSTEM
The concept of smart water system utilizes advances in
information technologies for system monitoring data and to
achieve greater efficiency in the resources allocation. In
addition to the increased efficiency in the water losses control,
prevention and early detection of leaks, the smart water
system also allows the development of best practice in the
management of assets by improving the efficiency of the
system in emerging areas, such as in the demand-oriented
distribution. Instead of simply following the existing practices
that pump water at high pressure in the distribution system to
reach distant customers, a more smart system could use real
time data, variable speed pumps, dynamic control valves, and
smart meters in order to balance the demand, minimize the
overpressure in aging pipelines and save energy (Global Water
Technologies, 2013).
The use of smart water system to improve the situation of
many networks characterized by degraded infrastructure,
irregular supplies, low levels of customer satisfaction or not
proportional bills to actual consumption. The smart water
system can lead to more sustainable water services, reducing
financial losses and enabling innovative business models to
serve the urban and rural population.
3.4 SMART WATER MANAGEMENT TECHNOLOGIES
3.4.1 SMART PIPE AND SENSOR NETWORKS
According to Lin and Liu (2009) the prototype of the smart pipe
is designed as a module unit with a monitoring capacity
expandable for future available sensors. With several smart
pipes installed in critic sections of a public water system, a real
time monitoring detects automatically the flow, the pressure,
leaks in pipelines and water quality, without changing the
operating conditions of the hydraulic circuit.
The individual sensors knots generally have four main parts: the
data collection and processing unit, transmission unit, power
management and sensors. The performance of each of these
sections, in terms of power consumption and reliability greatly
affects the overall performance of the sensors and the
network. Figure 3.1 illustrates a general diagram of smart pipes
and wireless sensor network.
Figure 3.1 – Scheme of a smart pipes and wireless sensor network,
(Sadeghioon et al., 2014).
Briefly, the smart wireless sensor network is a viable solution
for monitoring the state of conservation, the pressure and the
water losses control. The main advantage compared to other
methods of water losses control normally used is the
continuous monitoring throughout the network, without
operator intervention. Another advantage is the low energy
consumption of the wireless sensor network, allowing them to
remain operational for long periods without maintenance,
(Sadeghioon et al., 2014).
3.4.2 SMART WATER METERING
A water meter is a device used to measure the quantity of
water consumed in a building, while a smart metering is a
measuring device that has the ability to store and transmit data
consumption with frequency (Figure 3.2). Sometimes, the
smart metering is referred to as the "time of use in m3",
because in addition to measuring the volume consumed, also
records the date and time that the consumption occurs.
Therefore, while water meters are read monthly or twice a
month and a water bill is generated from this manual reading,
the smart metering can be read from a distance, and with
greater frequency, providing instant access to information on
the consumption of water for customers and managing entities
of the water supply network. These smart water meters are a
component of the Advanced Metering Infrastructure (AIM) that
water companies should choose to install (Alliance for Water
Efficiency, 2010).
Briefly, the smart water metering offers essentially the
opportunity to improve the balance between the provision of
access to drinking water, the right of a managing entity to be
payed for services rendered, as well as the joint responsibility
of all to conserve the already scarce water resources (Boyle et
al., 2013).
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Figure 3.2 – Scheme of the smart water metering technology
(Alliance for Water Efficiency, 2010).
3.4.3 GEOGRAPHIC INFORMATION SYSTEM – GIS
As regards the implementation of a Geographic Information
System (GIS), it must be understood that this tool can be
applied to various areas of study and, when applied to smart
water management technologies, allows us to have a clearer
idea of its evolution. The major advantage of a GIS is the
modulation of reality based on data and assumes a prominent
role in today's society because they are information systems
designed to collect, styling, store, receive, share, manipulate,
analyze and present information that is geographically
referenced (Worboys & Duckham, 2004).
The GIS plays a strong role in smart water management and for
the management entities, already provides a more complete
list of the components of the distribution network and their
spatial locations. With a sophisticated network communication
overlay on the water supply system, the data management with
GIS becomes absolutely critical.
Geographic Information Systems (GIS) allows incorporating the
spatial component to a model object oriented, allowing an
improvement in the planning and management of systems of
public networks and facilitating a clear evolution of spatial
models in the network.
3.4.4 CLOUD COMPUTING
The concept of cloud computing refers to the use of memory
and storage capacities and calculation of computers and
servers shared and linked through the Internet, by following
the principle of network computing.
The storage of data is done in servers which can be accessed
from anywhere in the world, at any time, without the need of
installing programs or storage of data in other devices. Access
to programs, services, and files is remote, via the Internet -
hence the allusion to the cloud. The use of this model is more
viable than the use of physical drives.
Furht and Escalante (2010) defines cloud computing as "a new
style of computing in which the resources are dynamically
scalable and often virtualized being provided as a service over
the internet" such as large repositories of virtualized resources,
such as hardware, development platforms and software, which
are easily accessible and can be dynamically configured so as to
adapt to different workloads with the intention to optimize
their use.
3.4.5 SUPERVISORY CONTROL AND DATA ACQUISITION –
SCADA
In general, the majority of public water services have embarked
on an online monitoring where the supervision, control and
data management is done through the system, known as
SCADA (Supervisory Control And Data Acquisition) (EPA, 2009).
In this way, SCADA is a system that allows an operator in a
central location in processes widely distributed will be able to
make changes to the set point in distant process controllers, to
open or close the valves or switches, to monitor alarms, and
gather information from measurement (Boyer, 2004).
Up to date, the more detailed data about the current state of
the water network in terms of flow, pressure and water quality
is collected using the SCADA systems located in reservoirs and
water tanks. Generally, has very limited surveillance
capabilities, online analysis and limited implementation in
pipes and valves within the water distribution networks.
In short, the SCADA systems are used to control dispersed
assets acquisition of centralized database where it is just as
important as the control. These systems of supervision, control
and management of data are used in various systems of
distribution, such as the distribution of water and waste water
systems, oil and gas pipelines, transmission concessionaire of
electrical power and rail and other public transport systems.
3.4.6 MODELS, TOOLS OF OPTIMIZATION AND DECISION
SUPPORT
The implementation of a common framework for measuring
performance based on a set of relevant indicators and data
applications and interfaces to support the decision of the
managing entities allows the interested parties to learn from
each other, to create trust and confidence in the solutions and
to monitor the progress (Airaksinen et al., 2015).
The hydraulic network and water quality models represent the
most effective and viable way to predict the behavior of the
water distribution system under a wide range of conditions of
demand and system failures.
In the other hand, the models of operations in real time
optimization (real time operations-optimization models),
expand the use of the smart water system in order to help
operators to improve the efficiency of the water network and
ensure more reliable operations and maximizing cost savings.
The models automatically read the data in real time, instantly
update the network model, show the characteristic parameters
of pump and treatment stations as well as the hours of
operation that will produce the lowest operating costs,
provided that they meet the objective requirements of the
system (Boulos & Wiley, 2013).
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3.5 ADVANTAGES OF THE SMART WATER MANAGEMENT
Some of the main advantages of smart water management are
a better understanding and analysis of water system, detection
of leaks, conservation and monitoring of water quality. The
implementation of the smart water system technologies allows
public services companies to be able to build a complete
database. In fact, having a detailed database also allows the
identification of the areas where water losses occur, enabling
public services companies to identify leaks and/or illegal
connections. The advantages of the smart water grid are
varied: from economic benefits, to water and energy
conservation, among others. In addition to the benefits listed
above, the efficiency of the system can improve customer
service. The wireless data transmission allows the client to
analyse his water use and potentially use water with a view of
persevering this resource. In fact, the consumers who chose the
electronic bill have reduced in a more significant and active way
its water consumption, in some cases, as high as 30%
(Martyusheva, 2014).
3.6 HITACHI: A RENOWNED COMPANY IN THE MARKET
Throughout the world, specific measures are being taken to
achieve a special type of city: the Smart City. In order to do so,
there are numerous companies associated with this
commitment, where Hitachi stands out among other large
international companies such as IBM or Schneider-Electric.
In April 2010, Hitachi has created an entire division focused on
smart cities. The Division of Innovation Projects and Social
Enterprise is based on experience and knowledge of the
companies in the group Hitachi. These companies have been
developing a wide range of social infrastructures, equipment
and information systems for the cities over many years. The
division aims to contribute to initiatives of a Smart City and
work with Japanese and foreign partners, developing and
promoting businesses related to the Smart Cities. Through
these companies, Hitachi helps cities to plan, implement and
develop systems that can operate efficiently solving current
problems. But, the visionary approach of Hitachi, is not only to
help make the cities more technologically advanced. The close
technological solutions rarely satisfy all interested parties of a
city, which include the city's administrators, residents,
companies, and those who manage it, meaning that the
stakeholders of a city often have different goals and focus on
different themes. The approach of Hitachi is to find solutions
that provide the ideal balance between all these interested
parties and specially to ensure the comfort and the
sustainability of society itself. Hitachi takes into account firstly
the economic characteristics, environmental and social issues
that the city faces and then helps to provide Smart cities
solutions to help solve the specific issues of that city. The main
objective is not only to solve the current problems, but also to
make the devolved systems simpler to enable solving future
problems (Hitachi, 2013).
4 CASE STUDY – SMART WATER MANAGEMENT
4.1 GENERAL CONTEXT
Currently there are more and technological solutions capable
of making the management of smart water and in this chapter
it will be shown an example, worldwide, of the smart water
management, made by a Portuguese company EPAL – Empresa
Pública de Águas Livres (Public Water Company) – in the
Portuguese capital. In Lisbon, the company has focused the
world's attention, due to the high level of efficiency,
particularly in the reduction of water losses and consequently
the reduction of operational costs.
In historical terms, the origin of EPAL was in 1868 with the
creation of the Companhia das Águas de Lisboa, CAL, the
concessionaire of water supply of the city of Lisbon during more
than 100 years. Only on April 21, 1991, by the decree-law no.
230/91, EPAL is transformed into an incorporated company of
capital fully public, taking advantage of the flexibility of
management required to implement the strategy of
development, going by the name of Empresa Portuguesa das
Águas Livres, S.A.. From 1993 is integrated in ADP Group –
Águas de Portugal SGPS, SA., and currently it is a company of
the State enterprise sector, 100% owned by ADP (EPAL, 2015).
The EPAL Company manages and operates a supply system that
integrates three subsystems: the Castelo de Bode, opened in
1987 and currently has a daily production capacity of
approximately 625,000 cubic meters, the Tejo, inaugurated in
1940, with daily production capacity of 400,000 m3 and the
Alviela which is in operation since 1880 (EPAL, 2015),
represented in Figure 4.1.
In terms of infrastructure, the water supply system in Lisbon
comprises 2 Surface water extractions, 23 groundwater
extractions, more than 700 miles of adductor pipelines, 28
reservoirs, 31 pumping stations and 21 posts of chlorination, 7
associated with the treatment and 14 associated with the
strengthening of chlorination.
The chlorination posts are composed of 18 chlorine dosage
posts and 3 sodium hypochlorite dosage posts (EPAL, 2013).
The water distribution network in the city of Lisbon is
composed of approximately 1,400 km of pipelines, with more
than 100,000 connection branches, 14 reservoirs, which allows
to store more than 400,000 cubic meters and 10 pumping
stations (EPAL, 2014b).
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Figure 4.1 – EPAL’s Supply network, (EPAL, 2013).
In the context of the market for the provision of water supply
services, according to the annual report for 2014, EPAL
comprises an area of 7,095 km2, with 347,151 direct clients, 17
municipal clients and 3 multimunicipally clients, who represent,
as a whole, 35 municipalities (including Lisbon), involving more
than 2.8 million clients (EPAL, 2014b).
These values correspond to a volume of water sold higher than
192 million cubic meters, with the indicators of financial
turnover and net profits for the period exceeding EUR 140
million and EUR 54 million, respectively (EPAL, 2014b).
In spite of this, the non-revenue water was always a problem
for EPAL, which during the 1990’s, the overall volume of non-
revenue water has stabilized at around 50 million cubic meters,
with a strong predominance of the losses in the distribution
network, Figure 4.2.
Figure 4.2 – Non-revenue water register by EPAL, (EPAL, 2014a).
According to the International Water Association, IWA, the
volume of water in the distribution system, whether imported
or extracted drinking water, is divided into billed water (BW)
and non-revenue water and even between the authorized and
unauthorized consumption. In a simplified form it may be
considered the billed water as the water charged to direct
clients added to water that is exported to other water entities,
which is actually the consumption that is effectively authorized
and billed. The non-revenue water includes not only the water
losses, but also the volume consumed by the supplier or
authorized agents, due to social commitments and the
legitimate use of fire service. A simplifying schematic of this
hydric balance in the supply system is presented in Figure 4.3.
Figure 4.3 – Hydric Balance, according to IWA.
The water losses at supply systems reflect a measure of the
quality of management and operation of the system and
consequently EPAL, as all the managing entities of water supply
systems, strives to control and reduce the volume of water lost.
As it can be seen in Figure 4.3, the water losses may be of two
types, apparent or real. The apparent or economic losses
correspond to illegal or theft consumption, while the real or
physical losses correspond to losses through leaks, ruptures or
burst pipelines, reservoirs or service connections up to the
point of where the client connects to it.
To emphasize that despite the increased monitoring and
control associated with technological advances, it is not
possible to calculate accurately through measurements the
volumes associated with each of the categories described
above. Therefore, when necessary, it turns to estimates or
extrapolations from existing records.
Due to heavy losses in Lisbon’s distribution system in the
1990s, which placed Lisbon far of the best cities in terms of non-
revenue water, EPAL has set the ambitious goal of reducing the
non-revenue water in Lisbon distribution network to
sustainable values, setting a goal of water losses of less than
15% by 2009, Figure 4.4.
Figure 4.4 – More Efficient Cities in terms of non-revenue water in
the 1990’s. EPAL’s goal for 2009, (EPAL, 2014a).
As it can be seen in Figure 4.4, the losses were stabilized at
about 25% of the collected water, and in order to reduce the
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losses in a decade for values less than 15 %, EPAL adopted a
well-defined strategy that focused on:
• Segmentation and continuous monitoring of the network;
• Development of analysis systems using internal resources;
• Optimization of the process of active water losses control;
• Continuous improvement based on the experience and results;
• Review process simple and effective given the complexity of distribution systems;
• Focus on essential and real cost control.
In relation to the water losses control, this strategy tries to
reach the Economic Losses Level (ELL). The ELL is the objective
value of management entities, in an attempt to minimize the
overall cost associated with the water lost in the system and
the activities carried out under the active water losses control,
meaning, the maximum investment in an attempt to reduce
water lost, that from which it is no longer economically viable,
because it is higher than the cost of water lost. In Figure 4.5 the
concept of ELL in a simplified manner.
Figure 4.5 – Scheme on the Concept of Economic Losses Level,
(Sardinha, et al., 2015).
In order to reduce the losses in the water distribution system,
EPAL has to improve the monitoring and control of water losses
in the supply system of Lisbon since the 1990s. Thus, EPAL has
developed key tools for the deployment of a monitoring system
that does not put in question the supply, in quantity and
quality:
• Geographical Information System (GIS);
• Management Information System for Customers (MISC);
• Digital Terrain Model (DTM);
• Hydraulic System Model.
In addition, EPAL measures District Monitoring Areas (DMA),
being that the strategy of sectorization and monitoring of the
network is based on the total distribution of the network by
sectors that can be analysed independently. The sectorization
of the network makes it possible to obtain advantages in terms
of quantity and quality of information available on the network
and its operation, the identification of consumers of each DMA
and abnormal night consumption and the management and
control of pressure in the distribution water network.
The IWA recommends that an DMA should have between 1,000
and 3,000 clients, but in urban areas with high population
density, such as the present case study, may group together
more than 3,000 clients, with a maximum limit of 5,000 clients.
This limitation relates only to the increased difficulty in the
identification and location of ruptures to DMA of higher
dimension.
In this context it may be subdivided if the DMA in relation to its
size in three categories: small, with less than 1,000 clients,
medium, between 1,000 and 3,000 clients, and large, with
more than 3,000 clients. These values are not universal and
absolute, but have been tested and validated for the case of
Lisbon. In this case, the distribution network is divided into 152
DMA as it is presented in Figure 4.6.
In order to carry out the collecting, management and
processing of the information of the water supply system of
Lisbon, EPAL uses various registration systems and
transmission of data, in particular data-Logging equipment.
These devices enable the automatic collecting data water
consumption, pressure, among other variables, through
meters, flow measurement or probes (pressure sensors, pH or
chlorine) directly installed on the network. The data collected
are transmitted remotely, through such devices to a central
database, where they are stored, offering to the managing
entity scans and records more frequent and reliable, reducing
the need for estimates.
In this context, EPAL has developed a system for the monitoring
and water losses control based on the DMA and data collected
remotely, that allows you to combine processes and integrate
the information relevant to the management of the network,
the WONE - Water Optimization of Network Efficiency.
The main objective of the WONE is to support the strategy of
EPAL in search of the optimization of the supply system,
focusing on efficiency and reduction of losses, providing
performance indicators of DMA. This software provides an
intuitive interface using internet, allowing multiple users at the
same time, besides it becomes possible to integrate other
management systems (GIS and MISC), aiming to the needs of
different areas of the management entity, and still allow the
statistical calculation, graphical presentation and alarms
integration. Thus, WONE integrates perfectly in the process of
optimization and improvement of the efficiency of the
distribution system deployed by EPAL, which is presented in
Figure 4.7.
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Figure 4.6 – District Monitoring Areas, DMA, Lisbon, (EPAL, 2013).
Figure 4.7 - Optimization and Efficiency improvement Process,
(EPAL, 2014b).
Finally, it should also highlight the effort of EPAL in
implementation of flow meters indicated for each strategic
location on the network, such as for example the entry and exit
of DMA, and the methodologies and innovative strategies for
the detection and localization of leaks, essential for the rapid
action and consequent reduction of water losses in the system.
4.2 RESULTS ANALYSIS
The analysis of this case study will be carried out based on the
results obtained by EPAL in the last decade, by considering this
time interval the most relevant for assessing the effects of the
measures implemented in the distribution system.
The implementation of the monitoring measures and active
water losses control in Lisbon’s supply system, allowed EPAL to
reduce the losses in the system by 17 %, in 2004, to less than
10% of the total volume captured in 2014, Figure 4.8.
Figure 4.8 – Non-revenue Water evolution at EPAL.
As it can be seen in Figure 4.8, there was a decrease in the
volume of non-revenue water in this decade, 45.7 Mm3 for 19.9
Mm3. This decrease was due mainly to the efforts of the EPAL
logged to control the losses in the distribution system, because
the losses in production and transport remained constant at
approximately 5% of the volume of the collected water. On the
other hand, the NRW in distribution system decreased by more
than 30 Mm3, in 2004, to approximately 8 Mm3 in 2014. It is
presented this significant evolution in water losses control in
the distribution system of EPAL in Figure 4.9, where it also
stands out that approximately half of the volume of water
produced is delivered to other management entities.
Figure 4.9 – Evolution of the hydric balance in EPAL’s supply system.
As mentioned, the policy of monitoring and water losses
control of EPAL has focused in particular on the distribution
system, for this have levels of NRW too high in comparison to
the system of production and transport. The strategy of EPAL
has enabled the reduction of the levels NRW in Lisbon
distribution network of 23.9 %, in 2004, to 8.1 %, in 2014, Figure
4.10. This decrease in the volume of NRW of 27 %, from 30 Mm3
to 8 Mm3, in 10 years, it is even more significant considering
the significant reduction in the total consumption.
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Figure 4.10 – Results of the policy of active water losses control in
the distribution system of EPAL.
As previously mentioned, EPAL defined at the end of the 1990s
the ambitious goal of reducing the non-revenue water in Lisbon
distribution network for sustainable values, setting a goal of
water losses of less than 15% by 2009. As it can be seen in
Figure 4.10, this objective has been achieved, and at this
moment the management of the distribution system of Lisbon
positions the EPAL in elite group of more efficient management
entities worldwide, Figure 4.11.
Figure 4.11 – More efficient Cities at non-revenue water level in
2014, (Sardinha, et al., 2015).
Associated with the efficiency gains, EPAL had still a decrease
in operating costs of supply network, shown in Figure 4.12.
Despite the reduction of these costs, the unit cost of water
produced was not sensitive to this variation and remained close
to the €0.30/L. This is mainly due to fixed costs of supply
network, the decrease in demand and an increase in this
decade of unit costs of External Supplies and Services (ESF), in
particular the electricity.
Figure 4.12 – Operational Costs and unitary cost of produced water.
Still the energy bill, which is the main constituent of the ESF,
contradicted the trend of growth in the market, due to the
gains associated with the energy optimization enabled by
monitoring and water losses control. In 7 years EPAL obtained
an energy saving of approximately 57 GWh, reducing the
energy bill by more than EUR 5 million. In addition to the energy
reduction, another more direct result and representative of the
policy of monitoring and water losses control, was the
reduction of the levels of NRW in the network, which allowed a
saving, in 7 years, about 100 Mm3, or EUR 50 million.
These results demonstrate the improvement of the efficiency
of the exploration of the supply network of Lisbon, with a
savings of more than EUR 55 million in just 7 years. For this, it
was necessary to invest in the sustainability of the distribution
network and in new technologies of information and
communication. In total, EPAL has invested approximately EUR
18 million in 10 years, approximately 5% of the total investment
in this period, to reach these levels of efficiency, Figure 4.13.
Figure 4.13 – Investment in water losses control and their financial
accumulated gains.
As it can be seen conclude by looking at Figure 4.13, the
investment made in monitoring and water losses control
obtained a recovery of investment in short term, allowing
further reduction in the overall costs in the operation of the
network, offering a saving of about EUR 37 million in 10 years
of operation.
But the investment is not linearly related with the financial
gains and EPAL defines the needs of investment through the
systematic calculation of the ELL, noting that the levels of actual
losses in Lisbon network reached at this moment this value. As
such, and recalling that the ELL is the objective value of
management entities, in an attempt to minimize the overall
costs associated with the water losses in the system and the
activities carried out under the active water losses control,
meaning that the maximum investment in an attempt to
reduce the water losses, that from which is no longer
economically viable, because it is higher than the cost of water
lost, is not justified at this present time, a financial effort. It
should be noted, that this situation can be changed at any time,
due to this value is sensitive to situations such as network
changes, legislation, consumptions, personnel and ESF costs as
well as the macroeconomic situation of the country.
10
Thus, the supply network has evolved into an economic,
financial and environmental situation more sustainable, which
is an objective that EPAL is proposed to achieve, and that all
other entities are looking for in the context of smart cities.
5 CORROLATION MODEL FOR ÁGUAS DO PORTO
5.1 GENERAL CONTEXT
The Águas do Porto of Porto’s City, Municipal Company, derives
from the Municipal Services of Water and Sanitation of Porto
(MSWSP), founded in April 1927. Currently, it has the granting
of water distribution and drainage of wastewater in the
municipality of Porto. It has a total of about 150,812 clients.
The system of water distribution to the city, Figure 5.1, is
composed of 6 reservoirs - Bonfim, Carvalhido, Congregados,
Nova Sintra, Pasteleira e Santo Isidro - which corresponds to a
total storage capacity of 125,450 m³, by a network of
distribution pipes with 718 km in length and by a set of
adductor pipelines whose length is 42 km. The distribution
network has approximately 64,000 domiciliary service
connections and the water distributed has origin at the
collecting point of Águas do Douro e Paiva, S. A., and is supplied
to the city of Porto by 12 points of delivery for the system at
low point (distribution network), which are distributed along
the two main adductors’ axis, a North along the Circunvalação
road and another to the South, which supplies the Reservoir of
Nova Sintra.
Figure 5.1 – System of adduction and distribution of supply network
of Porto City (Águas do Porto, 2015).
Through the success of the Project Porto Gravítico (2006-2012),
it was feasible to make the gravitational supply almost on the
whole, through restructuring the distribution network, in order
to extinguish the service of four pumping stations (Bonfim,
Nova Sintra, Pasteleira and Santo Isidro) of the municipal
system, maintaining currently active only the pumping station
of Congregados, to fill the area of higher quota city - DMA
Congregados Superior - whose gravitational supply is not
possible, for reasons associated with the topography of the
land.
At the moment, the distribution network of the city of Porto is
divided into 18 DMA. The company has opted for the
sectorization of the distribution network through the creation
of interior sub-DMA so that it is possible to carry out a more
effective monitoring and consumption control. Proof of this is
the fact that, in addition to the already existing 18 large DMA,
the water distribution network of Porto City is subdivided into
31 interior shut down sub-DMA.
5.2 CORROLATION MODEL
Considering the results obtained by EPAL in the optimization of
distribution network through the improvement of monitoring
and control of losses, it was estimated that the investment
required in order to be possible to obtain an equivalent level of
performance in the system of water supply from Porto’s City,
meaning for losses in the distribution network less than 10% by
2025, as previously set above. Therefore, the main
characteristics of the current system of distribution of Porto’s
City were assessed, Table 5.1.
Table 5.1 – Main characteristics of Águas do Porto distribution
system, (Águas do Porto, 2014).
Total Annual Volume (m3) 20 332 815
BW (m3) 15 962 429
NRW (m3) 4 370 386
(%) 21,5%
Total Clients - 150 812
As we can see in Table 5.1, the NRW in Águas do Porto
Company in the year of 2014 stood at 21.5 %, with more than
4 Mm3 non-revenue water, this amount being equivalent to
that which EPAL (Public Water Company in Lisbon) had in 2004,
but higher in comparison with the level that EPAL managed to
achieve in 2014. The level of NRW was the main factor of a
discriminant analysis that allowed determining the Águas do
Porto as the indicated entity to apply the correlation model.
The other factors that were also mostly favourable were the
initial level of implementation of DMA, the similar water
consumption diagram of Oporto and Lisbon and the equivalent
level of environmental awareness of both cities in terms of
energy and water management.
Thus, it was considered that the development of EPAL suffered
between 2004 and 2014, at the expense of the investment
made in monitoring and water losses control, could be
transposed to the distribution system of Porto’s City using the
method described in the flowchart in Figure 5.2.
11
Figure 5.2 - Flowchart of the correlation model.
As can be seen in Figure 5.2, the EPAL data was used to
estimate the major socio-economic indicators for determining
the investment required to reach a certain NRW level.
A statistically analysis to key indicators of the EPAL results for
the correlation model were made, in order to determine the
annual growth rates of the number of clients and billed water,
and the Investment in water losses control per reduced volume
of NRW and per client. Note that the determination of those
parameters per client are essential to correlate different size
water management companies, since they may have different
sizes but usually proportional to the number of clients.
The annual growth rate of the number of clients was obtained
through the average annual growth recorded by EPAL from
2004 to 2014, as the mean squared error (MSE) determined
from different types of regressions did not present acceptable
values to be considered a reliable indicator to the progress of
this parameter. Since so it was adopted an annual growth rate
of 0.3% for this correlation model.
In order to determine the billed water progression it was first
made a canonical correlation taking into account the evolution
of the number of clients in the distribution system on an
attempt to assess the dependence of billed water with the
number of clients.
As seen in Figure 5.3, there is no correlation between the
annual growth in the number of clients and the BW on the
results of EPAL, verifying that these are independent
parameters.
Figure 5.3 – Correlation between the annual growth rate of billed
water and number of clients.
Thus, it was evaluated the possibility of BW present a growth
that could be represented by a linear regression, polynomial or
logarithmic. The reduced value of MSE not allow it to take some
of these regressions as a parameter of the correlation model,
and taking this into account it was adopted the average growth
rate of BW, -0.3%. Note that it was determined that these
variables are independent, making from the outset the demand
a multivariate model, in terms of number of customers and BW.
The search model has allowed determining the evolution of the
number of customers and volume of BW at Porto supply
system.
Finally, it was analysed the correlation between the annual
investment per client effected by EPAL in the study decade with
the decrease of NRW by client of the following year. It was
considered with this analysis that the investment made in a
year on water losses control would only return results in the
following year. This analysis would be able to determine a
logistic regression for the investment required per client to
achieve a certain level of NRW, but the MSE values were not
considered acceptable to determine investment by this means.
AN
NU
AL
GR
OW
TH R
ATE
OF
BIL
LED
WA
TER
ANNUAL GROWTH RATE OF NUMBER OF CLIENTS
12
In this way it was determined the investment parameter's in
the water losses control per volume of NRW reduced and per
client with the average value of annual investment by reduction
of NRW of the following year and per client by the following
equation:
𝐼𝑁𝑉𝑁𝑅𝑊̅̅ ̅̅ ̅̅ ̅̅ ̅̅ =
∑ 𝐼𝑁𝑉𝑖𝑁𝑅𝑊𝑖+1⁄𝑛
𝑖=1
𝑛
(1)
that,
𝐼𝑁𝑉𝑁𝑅𝑊̅̅ ̅̅ ̅̅ ̅̅ ̅̅ – Annual investment average on water losses
control by decrease of NRW and by client;
𝐼𝑁𝑉𝑖 – Investment on the water losses by client in the year i;
𝑁𝑅𝑊𝑖+1 – Non-Revenue Water per client of the year i + 1.
The value obtained for the Investment parameter on the water
losses control by volume of NRW reduced and per client was
3.6 € / m3 / client / year.
With the parameters of the correlation model obtained was
even necessary to determine the volume corresponding to the
NRW goal level in 2025. From the BW and the NRW level
intended is possible to determine the volume of NRW and
water in the system for the year 2025, but to evaluate annually
the evolution of the system was assumed that the AP would
make an investment that allow a reduction in the volume of
NRW, constant until 2025. With the determination of the
evolution of the distribution network of Porto city, and as can
be seen in flowchart that appears in Figure 5.2, it were
determined all the parameters required to make the
determination of annual investment in the water losses control
needed to reach the NRW goal of 10% until 2025.
5.3 RESULTS ANALYSIS
After the determination of the correlation model indicators, it
was possible to relate the decrease of NRW per year with the
annual investment in the water losses control required in the
previous year, obtaining the investment plan and the evolution
of the distribution network features the next 10 years.
The total investment required in the AP, obtained through the
correlation model considering the indicators previously
determined was approximately 9.5 M € for the next decade,
allowing a reduction of more than 2.6 Mm3 of NRW in 10 years.
Are set forth in table 5.2 the main values obtained from the
correlation model, where highlights the level of NRW losses
and the total investment.
Table 5.2 – Estimate on the evolution of the main features in Águas
do Porto, based on EPAL.
Main features
Águas do Porto EPAL
2015 2025 2004 2014
Total Annual
Volume (Mm3) 20,3 17,3 127,0 101,0
BW (Mm3) 16,0 15,5 96,6 92,8
NRW
(Mm3) 4,4 1,7 30,4 8,2
(%) 21,5% 10,0% 23,9% 8,1%
Total Clients - 150 812 155 293 339 111 349 151
In Figure 5.4 and Figure 5.5 are represented some results
obtained graphically, allowing an immediate evaluation
of the evolution of NRW level in the Porto distribution
network and the required annual investment. In Figure
5.4 is presented the investment plan and the variation of
NRW level for the next 10 years, while the figure 5.5
represents the evolution of the water volumes associated
to NRW and BW in Porto distribution network.
Figure 5.4 – Investment in water losses control and the
corresponding evolution of the NRW to Águas do Porto Company.
Figure 5.5– Evolution of losses in the Distribution system of Águas
do Porto Company.
13
6 CONCLUSIONS AND RECOMMENDATIONS
6.1 CONCLUSIONS
In this present research, it is concluded that the technology
itself does not make a city a smart city, since it is necessary to
create a proper system to each city and efficient use of
innovative technologies associated with a worldwide
awareness of the society in relation to the sustainable
management and use of available resources. Through the
technological innovations, the smart cities can reduce costs,
increase quality and optimize different characteristic
parameters.
The water sector presents significant challenges, in particular
the effort to develop a smart water system, which translates to
a better control and monitoring of the network in order to
improve the efficiency of the system. According to the Global
Water Technologies (2013), the public water services need new
technologies to monitor our systems - providing real time
measurement of water consumption and warnings when the
conditions become critical.
The potential benefits of a smart water management include
the improvement of the water losses management, monitoring
of water quality, better management of droughts, and energy
savings. Thus, the smart water management in the cities is a
great way for the conservation, efficiency, and security
objectives to be achieved, once that Ervideira refers (2014)
"The non-revenue water translates annually in millions of
euros, translated into work expenses, chemicals and non-
recoverable energy ".
In this case study it was analysed the results achieved by EPAL
during the implementation of the measures for the monitoring
and water losses control in the distribution network of Lisbon.
The results obtained allowed to assess the high level of
efficiency achieved, in particular the reduction of water losses
and consequent reduction of costs, and associate it to the
investment made during the last decade.
This analysis allowed us to evaluate the efficiency gains and
savings in water that EPAL has achieved through the measures
that aim to optimize energy efficiency and reduce water losses.
Not only the levels of non-revenue water reached values in the
category of more efficient cities in the world, as the profits of
the company have been presenting historical highs.
Thus, it should be emphasized that the investment of EUR 18
million of EPAL policy on monitoring and water losses control
allowed the saving of approximately 57 GWh and 100 Mm3,
corresponding to an overall saving of more than EUR 37 million
in just 10 years.
Of further note, that at this moment the EPAL has reached the
maximum value from which is no longer economically viable
investment in water losses control, which is higher than the
cost associated with the lost water, meaning that it reached the
NEP. Thus, there is no need for additional effort in this area,
focusing on the EPAL stabilization of pressures and control of
transitional arrangements, with the aim of continuous
improvement of the operation of the system of distribution. It
should be noted, that the calculation of the Economic Losses
Level (ELL) is systematic and being sensitive to situations such
as network changes, legislation, consumptions, personnel costs
and External Supplies and Services (ESF) and, of course, the
macroeconomic situation of the country, may at any time
return to be an economically viable investment in water losses
control.
Finally, in relation to the excellent results obtained by EPAL, it
was estimated the investment necessary to achieve the goal of
water losses inferior to 10% by 2025, in the distribution
network of Porto Water Company. Despite the clear
differences in terms of the topography and the size of the
distribution systems, these systems had similarities that allow
a correlation of the results obtained by EPAL, specially taking
into account that the level of losses of EPAL in 2004 (23.9 %)
was comparable to Porto Water Company (21.5 %) in the
present. It was taken into account the fact that in 2004 EPAL,
as the Porto Water Company at the moment, had already
started the implementation of measures for the monitoring
and water losses control. With these assumptions, it was
considered that it would be more accurate the correlation of
the results obtained by EPAL for the distribution system of
Porto City in relation to the analysis of historical data of Porto
Water City to estimate the evolution of this system.
In this sense it is estimated that a total investment of around
EUR 9.5 million until 2025 would be sufficient to reduce the
losses in the distribution system of Porto City to 10 %, placing
the city at the level of the most efficient in the world.
6.2 RECOMMENDATIONS FOR FUTURE DEVELOPMENTS
As a result of this work appeared some aspects that proved
interesting for a more detailed approach. As the very
philosophy of sustainable management presupposes, it should
be continuously investigated points to be improved in the
process of looking for more efficient systems. In this sense, it is
recommended to perform a detailed analysis on the DMA for
different cities. The DMA, as stated, may have quite varied
characteristics, since geographical dimension, number of
clients, topography and infrastructure. Thus, increasing the
level of detail in the investigation of quality of service, losses,
investments and operating results, will allow an observation of
direct results of investments made in each DMA. The creation
of a database of results of DMA will allow the creation of
models of correlation at the level of DMA, instead of the
distribution system, allowing a financial analysis more accurate
and up to the level of infrastructure investment, maintenance
and operation of the network.
At this point it is also important to point out the importance of
the use of equipment and technological systems in innovative
exploitation of water distribution network, as key tools for a
14
smart water management, in particular smart pipes, sensor
networks, smart meters, cloud computing, SCADA,
geographical information systems and models of optimization
and decision support. All such equipment and systems referred
to will allow the collection, integration and processing of data
in real time and on a continuous basis, which enables an
efficient management in control and monitoring of water
losses and leaks, in control of obstructions to flow in conducts
and a more effective maintenance of infrastructure network by
preventing the degradation and premature aging of the same.
Finally, as is the case in the city of Lisbon, other cities should
proceed with the integration and development of policies in
the maturation of the water use, in particular the energy saving
and recycling of water and awareness of the increasingly
limitation this resource faces. This maturation of society is
essential for the successful implementation of a smart water
management.
15
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