SPORE@REIDS -A MULTIFLUID MICROGRID DEMONSTRATOR IN SINGAPORE

Abstract

ENGIE, NTU and Schneider Electric have joined forces to develop the first multifluid microgrid among the REIDS initiative in Singapore. This complex microgrid is composed of various assets coming from a range of different suppliers, and their integration into one common system is a major challenge. The management system made up of the EMS and the PMS as well as the SCADA is a common development effort which has to align the different primary objectives of each sub-unit and make them work as one coherent system. The tropical climate in Semakau is also an additional stress applied on the assets and the operating staff. First tests results are expected in the second half of 2018.

Full text

CIRED Workshop - Ljubljana, 7-8 June 2018
Paper 0082
Paper No 0082 Page 1 / 4
SPORE@REIDS – A MULTIFLUID MICROGRID DEMONSTRATOR IN SINGAPORE
Quentin ANTOINE Laurie PAZIENZA Stijn UYTTERHOEVEN
ENGIE Laborelec – Belgium ENGIE Laborelec – Belgium ENGIE Laborelec - Belgium
quentin.antoine@engie.com laurie.pazienza@engie.com stijn.uytterhoeven@engie.com
ABSTRACT
ENGIE, NTU and Schneider Electric have joined forces
to develop the first multifluid microgrid among the
REIDS initiative in Singapore. This complex microgrid is
composed of various assets coming from a range of
different suppliers, and their integration into one
common system is a major challenge. The management
system made up of the EMS and the PMS as well as the
SCADA is a common development effort which has to
align the different primary objectives of each sub-unit
and make them work as one coherent system. The tropical
climate in Semakau is also an additional stress applied
on the assets and the operating staff. First tests results
are expected in the second half of 2018.
INTRODUCTION
The Sustainable Powering of Off-grid REgions is a joint
project started in 2015 between ENGIE, Nanyang
Technological University (NTU) and Schneider Electric,
with the goal of developing a multi-fluid microgrid
among the REIDS initiative in Singapore. The
Renewable Energy Integration Demonstrator in
Singapore is an initiative led by the NTU on the Semakau
Island, whose purpose is to facilitate the development
and market penetration of the energy technologies suited
for tropical conditions in Southeast Asia via the
implementation and testing of various microgrid systems
within the island.
This initiatives includes many partners coming from all
over the world and from all corners of the energy
industry. ENGIE and Schneider Electric are at the
forefront of this initiative, with the development of the
first multi-fluid microgrid in the island. [1]
A COMPLEX MULTIFLUID MICROGRID
One of the objective of the SPORE microgrid, besides
promoting renewable energy sources, is also to
demonstrate the feasibility of dealing with several energy
fluids in one system. Besides the classical elements found
in most microgrids of today – typically a wind turbine,
some PV panels, batteries to store the renewable energy
produced and diesel generators (gensets) to ensure grid
stability and reliability - the SPORE microgrid includes
a Virtual Synchronous Generator (VSG), a complete
hydrogen (H2) conversion and storage system with a
hydrogen refuelling station as well as biogas driven
generator set.
The Virtual Synchronous Generator is currently
developed by Schneider Electric and will be tested in the
challenging conditions of Semakau Island. The VSG is
composed of a classic Li-ion battery, PV panels as the
power source, a specific inverter and of course an
innovative set of control algorithms. Its purpose is to
eventually substitute the genset as the grid-forming
element and thus allow a possible penetration of 100% of
renewable energy within the microgrid. The idea behind
this system is to replace the rotational inertia provided
classically by generators with an artificial inertia
provided by the inverter, with the help of the battery. [2]
In fact, with its very-fast response time, the inverter could
react to an unbalance between production and
consumption by injecting/withdrawing power thanks to
the battery which can deliver/accumulate a certain
amount of energy over a limited period of time. This
would allow other producing assets to adapt to any
change in power required, the grid remaining stable in the
meantime. This kind of technology is paramount in order
to improve further the share of renewable energy
resources, which are almost always non-rotating
producing units (PV panels and wind turbines are
connected to the power grid through inverters, thus
without any actual inertia).
Figure 1: Wind turbine & PV panels in Semakau Island

CIRED Workshop - Ljubljana, 7-8 June 2018
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The H2 system is composed of the following elements:
an electrolyser, a H2 storage tank, a fuel cell and a
refuelling station for a fuel cell electric vehicle. The
philosophy of the system is that it can serve two
purposes. Firstly, the bundle electrolyser-H2 tank-fuel
cell can be seen on a functionality level as the equivalent
of a storage unit, which can store the energy produced by
renewable sources as hydrogen in the H2 tank. Secondly,
the refuelling station can use some of the hydrogen stored
in the tank to refuel vehicles and thus promote an
emission-free mobility.
The biogas generator is part of a simulated biogas system,
which also includes Compressed Natural Gas (CNG)
bundles. The biogas generator is similar to a classical
genset in terms of functionality, the only difference being
the use of biogas instead of diesel as fuel. The purpose of
CNG bundles is to emulate the production of biogas
through the disposal of organic waste. Energy is thus
produced while disposing of wastes, a true win-win
situation.
Due to the lack of suitable and flexible power
consumption present on the island, another essential
element of the microgrid is the load bench, which not
only allows the power produced to be consumed (without
this balance between production and consumption, the
grid does not exist), but also permits to test various use-
cases such as a sudden drop of the load or even worse a
sudden increase, which is always challenging for the
power grid since it endangers the power balance thus
apply stresses on the grid.
Finally, all of these various units could not operate
together and function as a whole without a proper
management system. The main components of such a
system are the Power Management System (PMS), the
Energy Management System (EMS) and the Supervisory
Control And Data Acquisition (SCADA), which will be
detailed hereafter.
MANAGEMENT SYSTEM DESIGN
The management system scheme is illustrated in Figure
3. It can be seen that the three main bricks PMS, EMS
and SCADA are sequential in their functionalities and
interactions.
The PMS purpose is to ensure the stability of the grid at
any moment, including but not limited to the
aforementioned power balance and the power quality,
which is notably about keeping the voltage and frequency
levels within the admissible limits. [3] The PMS is
straight connected to all the assets and is able to send
instructions to all of them. Some assets are entirely
controlled by this system while others are just getting set
points which are then incorporated by their own internal
control system. In order to ensure the power balance, the
PMS must not only deal with the available power
resources, which are not always predictable like notably
the solar panels or the wind turbines, but also with the
reactivity capabilities of each of them. A sudden change
in the consumption will be managed only if the
production assets can react fast enough and adjust their
production.
The SCADA serves as the interface between the entire
microgrid process and the user, or rather in this case the
operators who will proceed with the academical tests. Its
purpose is to be able to monitor and interact to some
extent with the operations of the microgrid. Boundaries
have to be clearly established between the
responsibilities of the PMS and the parameters that can
be controlled by the SCADA user. If some exchanges are
Figure 2 : Schematic of the SPORE microgrid

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foreseen in the management system design between the
end-user and the PMS itself (internal parameters settings
for example), this will occur via the SCADA interface.
The EMS purpose is threefold. First, the EMS aims at
making the most of the multi-fluid aspect of the
microgrid and thus maximizing the synergies between all
the technology bricks.
Secondly and more classically, a focus is put on short-
term optimisation, which consists in choosing among the
assets available the most appropriate production and
storage means to supply the power demand while
minimizing OPEX and environmental impact. This
second objective relies heavily on weather and
consumption forecasts.
Finally, the EMS proceeds to a mid-term optimization on
the use of the various assets and their maintenance
schedule, with a view to maximize the lifetime of all
assets and minimize replacement costs. Transversally to
all these objectives, the EMS is expected to remain
customer-focused, meaning that the expectations from
the customers are taken into account in all optimizations
to guarantee the quality of the electrical supply as well as
the fine-tuning of the optimization priorities based on the
customer choices.
Figure 3: Management system scheme
THE CHALLENGE OF INTEGRATION
A major challenge in the making of the SPORE
microgrid is the integration of different technologies in
one coherent and functional system.
The various elements in the microgrid, including but not
limited to the assets, are brought by various partners and
have to be integrated in one common system. This
induces significant challenges in terms of interoperability
among the assets, the communication chains and the
management systems.The interface between the EMS
and PMS is, notably, a key development in this project.
Two systems designed by two different companies, each
having their own set of proprietary algorithms and coding
languages, with a different set of objectives, must be
brought together in order to obtain a functioning global
system. This global system is thus expected to achieve
both sets of objectives.
In order to achieve this goal, both development teams
have to reach a common vision on the principles behind
each individual units, otherwise no common solution can
be figured out. Indeed, before deciding which signals will
be sent from one unit to the other (and the corresponding
technical modalities), which is the interface in itself, an
agreement has to be found on the inner logics of each
unit. Some fine-tuning (up- or downgrade) may be
required and a clear boundary has to be drawn between
the two systems responsibilities in the management
system, otherwise no interface can be developed.
In other words, before agreeing on the interface itself, the
development teams must agree on what each individual
unit can or cannot do.
Of course there are other intercompatibility issues,
notably regarding communication protocols between
each assets and the unified communication architecture,
with the PMS in charge. A single database must be built
to integrate all inputs and outputs (I/O) signals. These can
vary widely among the command signals, the
measurements or the status and alarm signals. It is thus
not a small feat to assemble all of these and correctly
establish a map of the communications among all
different units (EMS, PMS, SCADA and the assets).
Another point of attention regarding the integration is the
global operating modes of the overall system, which has
to be carefully built based on each asset’s features,
regulation and technical limits, but also on the basis of
the general vision of the microgrid operations. What does
this system aim to test? What will be automatically
controlled and what will be controlled by the user
through the SCADA interface? Those are examples of
questions that need to be addressed when designing the
global operating modes of the system.
IMPACT OF CLIMATIC CONDITIONS
The tropical climate on Semakau Island induce
challenges not only for human work but also on a
technical level. It is a euphemism to say that the climate
is harsh on the Singaporean Island. With an average
relative humidity above 97% and a temperature never
below 25°C during a whole year and often exceeding 30
degrees, the strain on the human body is severe. [4]
Working shifts have to be carefully determined in order
to limit the burden on the workers, otherwise there is an
increased risk of reduced attention and focus capability,
which in the context of a research project with dangerous
voltages could prove to be catastrophic.
But more importantly these conditions consist in a threat

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to the microgrid assets themselves. These assets include
components that were not specifically designed and
tested for such climatic extremes. The power electronics
notably, which are part of almost every assets on the
microgrid, present a myriad of components which could
be harmed at some point.
For PV panels inverters, the damages would likely be
limited, at worst the destruction of the asset itself.
However for more critical assets like the H2 elements for
example, such failures could again be catastrophic,
endangering potentially not only the entire microgrid
infrastructure, but the safe-keeping of the staff as well.
A careful maintenance has thus to be performed on every
component and this issue must be a major point of
attention during the operations of the microgrid. The
analysis of the impact of such extreme climate on the
assets behaviour, efficiency and lifetime will be one of
the project outputs, along with a characterization of the
microgrid technical capabilities and the performance of
the EMS optimization scheme.
CONCLUSION
The SPORE @ REIDS project aims at facilitating the
development and market penetration of renewable energy
technologies in Southeast Asia, via the implementation
and testing of various microgrid systems in Semakau
island, a landfill located in Singapore Bay. The unique
properties of this megawatt demonstrator lie in the
capability to handle multi-fluid technologies, the
incorporation of a special developed EMS/PMS
management system, the incorporation of a virtual
synchronous generator and the ability of the technologies
to resist the harsh tropical climate. The virtual
synchronous generator, which is PV-inverter based and
extended with a battery storage on the DC-bus, enables
grid-forming capability and stability thanks to an
increase in artificial inertia. The demonstrator setup is a
test-bench for different technologies, to be tested
thoroughly in the coming months/years, and to be
evaluated on different technological aspects, such as
integration inside multi-vendor, multi-fluid microgrids.
REFERENCES
[1]
S. Chew, H. Devos et S. Souquet, «Engie and
Schneider Electric Microgrid on Semakau Island,»
Schneider Electric - ENGIE,
2017. [En ligne].
Available: https://www.schneider-
electric.com/en/about-us/press/press-
release/2017/10-20-release-engie-partnership.jsp.
[Accès le 19 March 2018].
[2]
T. Ujjwol, S. Dipresh, M. Manisha et B. Bishnu,
«Virtual Inertia: Current Trends and F
uture
Directions,» MDPI - Applied Sciences, n°
%1June
26, p. 29, 2017.
[3]
N. Hatziargyriou, Microgrids Architectures and
Control, Chichester, West Sussex, United Kingdom:
John Wiley and Sons Ltd, 2014.
[4]
M. S. Singapore, «Climate of Singapore,» Na
tional
Environment Agency Singapore, [En ligne].
Available: http://www.weather.gov.sg/climate-
climate-of-singapore/. [Accès le 19 March 2018].