Special Issue

Smart Grid

RelatedRelated productproduct

Storage Battery Systems for Smart Community

1.

INTRODUCTION

Since the Great East Japan Earthquake happened in2011, questions are raised about nuclear power which
account for 30% of Japanese total electricity, and currently most of the nuclear power stations are suspending
operation. Due to the suspension, power supply is tightand electric power charges are raised. On the other hand,
Feed-in Tariff Law for renewable energy was started July,
2012, and migration from nuclear power to renewableenergy will possibly be accelerated. In this situation, electricity consumption and electric power charge reduction
activity is implemented, by peak cut and/or peak shiftusing PV(Photovoltaic) and storage battery.
Furukawa Electric Company (FEC) received an order of“Consignment of verification research service for promoting the introduction of smart energy system” from New
Energy and Global Warming Countermeasures / Electricity
Storage System Promotion Division, Environment andAgriculture Bureau, Kanagawa Prefecture. FEC is proceeding with the verification test which is characterized byan effective peak-cut with even a small battery capacity byusing stationary Lithium-ion storage battery (LiB) or
Electric vehicle (EV) as a storage battery.

2.

PV（3 kW） PV（14 kW）＋PCS＋PCSIP NW Smart controller
ユーザ負荷
User load

FEC incharge ofthis part

EV-PCS
Charge/Discharge

Visualize

PCS（10 kVA）

FEC
LiBOriginal（12.5 kWh） screen

Charge/Discharge

Nissan LEAF
(24 kWh)：Communication path
：Power path
Figure 1 System configuration.

Breakdown of Power
Oct.1st 2011 (Mon)

SYSTEM CONFIGURATIONThe system configuration is shown in Figure 1. The system consists of PV panel (PV: 17 kW), LiB (12.5 kWh) +Power Conditioning System (PCS) (10 kW [10 kVA]), EV(Nissan LEAF: 24 kWh) + PCS (10 kW [10 kVA]), Energy
management system (EMS) and Visualization user interface. FEC is in charge of all the components except forthe PV panel.

3.

Commercial AC line

BASIC ACTION

The basic action of the system is to control the battery(LiB + EV) discharging in order not to exceed the preset
criterion amount of grid power by monitoring both PV
power and grid power purchasing from an electric powercompany. A daily Power consumption chart (a chart showing consumed power in a day, PV power and discharge
from LiB and EV) is shown in Figure 2, and a monthly
cumulative power consumption chart in comparison withtargeted power consumption as shown in Figure 3 can bedisplayed. These actions encourage user’s sense of
reduced power consumption and help a planed use ofpower.

Figure 2 Daily power consumption charts.

Electric power charge
Oct.4th 2012 (Thu)Current amount
Yen

Expected this monthUsage rate

Target amount

Yen

Usage prediction

Yen
Last monthcomparison

Last year
comparison

Yen

Yen

Yen

Yen

Figure 3 Monthly cumulative power consumption charts.

Furukawa Review, No. 43

201334

Storage Battery Systems for Smart Community

4.

FEATURES

4.1 LiB + PCSThis LiB has approximately 4000 times of cycle life at 80%
depth of discharge and can be used for more than 10 years
with a daily repetitive discharge and charge.
4.2 EV + PCS
The biggest feature of this system is the grid connection
for the first time in the industry (Figure 4). Grid connectionmeans to discharge from the battery without shutting
power receiving from the outside such as an electric
power company. Deliberations for grid connection andapproval of the electric power company are required. As
this is the first time in the industry, a lot of attention is paid
from others.

Figure 4 Electric Vehicle and a power conditioning system.

4.3 EMSThe main role of the system is to give discharge commands towards two batteries, to avoid exceeding the preset criterion amount of grid power. By monitoring both PV
power and grid power amount, discharging power
amount is defined. As several hours of discharging fromthe battery are required against peak power of 160 kW,
various constrains are given in the control algorithm foran effective utilization of the small amount of storedpower. Detailed explanation of the control algorithm is notmade in here; this system can correspond to various dailyload curves.
4.4 Visualization
As described previously, power consumption in a day andcumulative power consumption in a month are displayedin charts, and receiving power amount from the grid canbe controlled. The daily power consumption charts show
not only power consumption but also generated powerand discharged power amounts, and if power consumption tends to exceed preset power consumption criterionin spite of charging and discharging, an alarm function isrecommended to be installed to the system. Furthermore,remaining battery capacity of LiB and EV are indicated,and consumers can judge if high-loaded equipments canbe used in time zones of high power consuming.

5.

VERIFICATION TEST RESULTS AND
TASKSThe verification test started on August 1st, 2012 and willcontinue until the end of March in this year. Due to thehotter summer than usual, in some days, the maximum
power consumption was higher than in the previous summer by more than 30 kW. Therefore, the system was notable to follow the demands in such a condition. Battery
capacity was designed based on the actual result in theprevious year. This was influenced by the higher than
expected power consumption of the year 2012. In one
case, the battery became empty during the peak period,and in another case, the battery was completely discharged before noon, due to the hot summer. Furthermore,
the building in Kanagawa Industrial Technology Center
had a lot of meeting rooms. And a daily power consumption chart types were differed depends on the usage ofthe meeting rooms. Then, in some cases at the beginningof the verification test, the system could not follow properly.
We found that the more detailed control and the power
consumption prediction are necessary for recovery. Then,
we clarified the necessary control for EMS based on thedata in August, and improved. With these actions the system followed well to peak cut/shift. We confirm our fulfillment of the initial purpose. From now, data collection andsystem operation confirmation in Winter season will beconducted.

6.

CONCLUSION

Major feature of this verification test is not only achievement of peak cut/shift by controlling multiple batteries but
also grid connection of EV-PCS. Merits of EV usage arefollowings. When there are multiple EVs, ①Even if thebattery capacity is lost, it can be replaced instantly, ②Effective utilization in the event of a disaster is possible bymaking the battery movable. From here on, we believe
the following improvements are important. One is cost
reduction to make this smart energy system possible tobe used widely. The other is to make this system availableto make a choice from the various controls, because theEMS control may vary slightly depending on the facility tobe introduced.
For more information please contact:
Broadband Products Division
Telecommunications Company
TEL: +81-463-24-8446 FAX: +81-463-24-8491

Furukawa Review, No. 43

201335