［ Control of Power Demand & Supply and Grid Power System ］

Development and Demonstrationof Next-Generation Energy System
on Demand Side ( Yokohama SmartCity Project)
Keywords

Smart grid, Demand response (DR), Next-generation energy system, Smart BEMS, Lithium ion battery system, Charge/discharge
EV for Charging and discharging

Abstract

In the energy ﬁeld, various demonstration programs have recently been
conducted relating to smart grids development. The Yokohama Smart City
Project is one such project for the purpose of establishing a smart energy model
for a wide-area metropolis. As one of the project members, Meidensha Corporation
has been conducting the development and demonstration of a next-generationenergy system based on the new technological concept.
Under this veriﬁcation project, we developed a smart Building Energy
Management System (BEMS) and lithium ion battery system in combination withan existing energy system. We aim to streamline the system and realize making
our system smart grids ready. In addition, we aim to make a more advanced system by implementing energy control among multiple facilities in liaison withsmart BEMSs.

1 Preface
Recently, a new concept called “smart city” or“smart community” is getting increased attention.
This concept refers to the building of a new social
system with signiﬁcantly increased overall efﬁciency of cities by using measures optimizing the energy
efﬁciency level of districts. In Japan, various demonstration projects have begun to realize such newconcept. Against this background, the Yokohama
Smart City Project (YSCP) is a demonstration project and a joint project promoted by Yokohama Cityand private enterprises. For this project, a largescale veriﬁcation is carried out based on the smartgrids. As one of the project members, we conduct
the development and demonstration for a next-generation energy system based on the aforementioned
new concept.
This paper introduces our system developed
thus far and the proﬁle of the demonstration project
which we joined since Fiscal 2012.

2 Outline of the Demonstration Project
The proﬁle demonstration project is shown
below.

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Takashi Uyama

MEIDEN REVIEW Series No.162 2014 No.3

( 1) Development of the smart Building Energy
Management System (BEMS) applicable to thesmart grids( 2 ) Development of a large-scale stationary battery system using lithium ion batteries( 3 ) Establishment of a next-generation energy
system by applying BEMS to the existing energy
systems

3 The Developed System
3.1 Smart BEMS
The purpose of the smart grid is to shape thebalanced energy efﬁciency at the districts level by
sharing the information of energy supply anddemand. In exchange for receiving additional incentive at the electricity user side, it is also necessary
to adjust the power demand, a system of Demand
Response (DR) for the overall local energy efﬁciencies. On top of the conventional BEMS, we built asmart grids-ready smart BEMS by incorporating theelements listed below. Fig. 1 shows an operation
model of our smart BEMS.
( 1) Communication function with the host system
By managing information of power consumption at a target facility, our system transmits such

information periodically to the host system like theCommunity Energy Management System (CEMS),
etc. Such data are aggregated at the host system
Host system operator

DR signal

DRPower
consumption
data

Incentive

CEMS, etc.

Electricity user

SmartBEMS

Operation
dataRole ①: Communication function
with host systems
Role ②: integrate control of energy
supplying facilities

DR control… Energy supplying facilities

Fig. 1

Operation Model of our Smart Grid

When an electricity user receives DR-related information andresponds to it, it is possible to obtain an incentive based on thepast energy usage records.

and are used for the energy demanded and supply
planning in the districts. On the other hand, the hostsystem occasionally distributes the DR signal toeach electricity user as a target power consumption
level. This information contains the incentive data;
therefore, when an electricity user conducts a DR,
the system records an incentive based on the past
power consumption records.
( 2 ) Integrate control for energy supplying facilities
Fig. 2 shows the outline of integrated control
by the smart BEMS. In commercial facilities, energy
is supplied to the local load by the combination ofvarious energy supplying facilities such as theCombined Heat & Power (CHP) and energy storage
system, solar power system, battery system, heatsource equipment, and thermal storage system. The
smart BEMS computes an entire energy operation
plan by factoring load patterns projection, mechanical characteristics, and energy information such as
the DR signal. Based on such an energy operation
plan, we conduct integrated control for the energy
supplying facilities to realize the efﬁcient operation.
As a result, DR control to adjust the amount of
the grid power to be purchased becomes possible

Smart BEMS

Energy supplying facility
Mechanical characteristics
and others

Predicted load pattern
・Power demand
・Thermal demand

Totally computing
the plan relating to
the energy demandin terms of:・Control of energy
supplying facilities
・Purchase of externalenergy・Ratings
・Efficiencies for respective electricityusers
・Energy storage characteristics
・No. of startups/time-zone limitations
・End of EV battery charge at thespecified timeOutput

Integrate control
based on the planCharge
Discharge

Energy-related information

・Minimum environmental impact
・Energy cost minimum(Factoring incentive)

・Contract power demand volume
・Energy unit price・Prime unit of CO2 emission
・DR signal, etc.

…

Purpose of operation

Energy operation in line with the purposes:
・Auto-responding type DR according in line with the term of
the incentive package
・Efficient energy supply in response to the occasionally andconstantly changing loads
・Energy operation considering environmental impactFig. 2Discharge

ChargeEnergy supply

Loads in the premises

Integrate Control by the Smart BEMS

Auto-response type DR control and efﬁcient energy management in facilities can be performed by the integrate control for the nextgeneration energy system.

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to base on the reserve power such as the number ofenergy supplying units in operation and operational
outputs.
To accomplish DR control in line with the DR
signals, it is necessary to determine the energy
operation plan in advance because it is the basis forcontrol. In addition, this plan calls for the electiveenergy operation in the target optimal energy management for facilities. Based on afore-mentioned
energy operation plan and by comparing the condition before and after the DR, we can assess if theresponse to each DR signal is correct or not.
For this purpose, under normal conditions weconduct the control based on the energy operation
plan to improve the energy usage efﬁciency in theoverall facilities. In the case of DR control, webenchmark the said operation plan. By responding
to the load changes and by selecting most efﬁciently working conditions of the energy supplying facilities within the power reserve, we realize effectiveenergy control.
When the aforementioned series DR-related
operations (such as demand control, data transmission/acquisition, judgment and control to receive orrefuse responses) are automated, we can realize anauto-response type DR approach.

3.2 Large-Scale Stationary Lithium Ion
Battery System
In order to add some latitude in energy control
by the smart BEMS, it is necessary to set up ameans to shift energy in our time and space.
Therefore, we have applied a technology of lithium
ion batteries for Electric Vehicles (EV). In so doing,
it is possible to establish a large-scale stationary
battery system featuring low cost, high safety, andlong operational life.
In the building and making this system, NEC
Corporation was in charge of the production of lithium ion batteries and we were in charge of the Power
Conversion System (PCS).

3.3 Application of the Developed System
When existing energy supplying facilities are
combined with lithium ion battery systems, it is possible to secure an energy reserve for power demandand supply balancing. In addition, by performing thecentral control to existing energy supplying facilities
by using the smart BEMS, we can streamline theenergy use and by going BEMS, such improved
energy system could be connected to smart grids.

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Fig. 3

Yokohama World Porters

Located in an area with various types of facilities, it offers theshopping mall, tourist spots, and walking courses − very popularplaces.

4 Outline of the Demonstration Project
4.1 Demonstration Project Site
The demonstration work is conducted at theYokohama World Porters, a big shopping mall in
Yokohama City. Fig. 3 shows an external appearance of the facilities.
In these facilities, a CHP is introduced for double purposes efﬁciency improvements by the combination of power peak-shaving and waste heatrecovery. This demonstration project aims to apply
the developed system to existing energy systems inorder to build a next-generation energy system.
Since the Yokohama World Porters are thecommercial facilities in operation, there are many
restrictions relating to system introduction and energy operations. By solving each problem, we aim tobuild a model of turning the existing facilities intosmart facilities.

4.2 Demonstration SystemFig. 4 shows an outline of the demonstration
system. The smart BEMS and a lithium ion battery
system were newly introduced and combined withthe existing dispersion type power source. Fig. 5
shows an operator console for the smart BEMS.

4.3 Operation
Since commercial facilities are required to offer
comfort to visitors, it is difﬁcult to perform energy
operation by giving restrictions to the load side. For
this reason, objects of energy control are limited
only to the energy supplying facilities. As a result,
we realize energy usage efﬁciencies for the auto-

Existingenergy system
mainly basedon the CHP

Use ofenergy storage
systems and EV
for charging
discharging

Realize DR

Improve energy
efficiencies foroverall facilities

Building an “effective energy operation system byinter-linking between CHP and energy storage system(including EV for charging and discharging) by the
introduction of the smart BEMS
Grid power

Fig. 5City gas

Operator Console for the Smart BEMS

By comprehensive control of energy supplying facilities from thisBEMS system, advanced energy operation is possible.

(Electricity)(Gas)
Output adjustment for distributed
energy resource

Lithium ion
battery system

CHP(Waste hot water)
Key device to givelatitude in energy
demand and supply
control by its power
demand shifting
Heat
exchanger

Absorption
chiller

Absorption
chiller/heater(Hot/cold water)
Control・If there is still a power reserve margin inbaseline operating conditions, output adjustment becomes possible in any given timing.
・Flexibly respond to the DR signal which calls
for a fast response.
Power demand shift by energy storage

Smart
BEMS
Power load

Fig. 4Heat load0

response type DR and for the overall facilities without giving restrictions to the operation of load
machines.
In actual operation, however, it is necessary tosecure an energy reserve for adjustments and also
perform adequate control within the energy reserve
range. In this demonstration project, the energy
reserve is secured based on a combination of “output regulation of distributed energy resources” and“power demand shift by using energy storage
device.” In so doing, we realized the project goal ofDistributed
energy resource(Moving-uptrend)213

Output Output

2①(Depressing trend)

1

DisDisDischarge charge charge

24

TimeCharge Charge Charge

1Fig. 6②Energy storage

DR control

Outline of the Demonstration System

By interlinking between the distributed energy resources and energy storage device, we build a complex energy system which
can meet the various applications.

Add up the power
reserve for adjustment by combining
each feature・Ordinary power demand shift approach
・There are some limitations in plan changing
timing because the daily unit level energy
budget has to be established.

Power demandDistributedenergy resource (underrestriction onoperationaloutput)

Interlinking

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Outline of DR Method

With appropriate control within the reserved power for adjustment, effective DR control became possible.

the efﬁcient energy operation.
Fig. 6 shows an outline of the DR method. By
combining the features of the distributed energy
resources and the energy storage devices, more
effective DR control becomes possible. By using
DR, the peak shaving becomes possible and canabsorb surplus power from the local solar power.
During regular energy operation without DRcontrol, it is conducted by the optimized control considering both factors: environmental impact andeconomy.
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5 Postscript
Based on the on-going project introduced inthis paper, we will continue to put our energy control
technologies further to the control of multiple facilities by interlinking with other smart BEMS blocks
under the control of other project members. During
the term of this demonstration project, which is26

MEIDEN REVIEW Series No.162 2014 No.3

scheduled to be ﬁnished by the end of Fiscal 2014,
we would like to focus our attention on the demonstration project for the purpose of making the existing
facilities go smart in realizing a smart community.
・All product and company names mentioned in this paper are
the trademarks and/or service marks of their respective owners.