IEEE Electrification Magazine - September 2015 - 5

International Smart Grid and Community Projects (2009)

Lyon (France)
Zero Energy Building, Electric
Vehicle Sharing, and Energy Audit
Demonstration in Redeveloped
City

Malaga (Spain)
EV Charging
Infrastructure and
Driver Navigation
System

Manchester (United Kingdom)
Wind Power Fluctuation Is
Absorbed by Water Heater
Type Heat Pump
New Mexico (United States)
Micro Grid
Demonstration in Los
Alamos and
Albuquerque

Maui Island (United States)
Direct Control Against
EV to Absorb a
Sudden Rump of
Renewable Source

Indonesia Power Quality
Management
at Industrial Park

Figure 2. NEDO's smart grid and communication-related international demonstration projects in 2010.

such as PVs and wind power, usually
fluctuates. This renewable energy
fluctuation affects the stability of a
power system's frequency when
those resources are introduced to the
power system. For example, there is a
concern that the high penetration of
wind turbines may make it difficult
to keep system frequencies within
operational standards in small
utilities in Japan. Therefore, those
utilities in Japan introduced an upper
limit of the amount of connectable
wind-generated capacity within their
systems in 2003. Since 2013, The Ministry of Economy, Trade and Industry
started a feed-in tariff (FIT) rate for
renewable energy. After the introduction of the FIT, many applications of
PV connection went to each utility.
The total capacity became higher
than the season's peak demand. So,
the limitation of connectable PV
capacity was discussed, and each
utility announced several constraints
for the PV connections. For example,
Hokkaido Electric announced in 2014

that only large-scale PV stations with
battery storage are allowed to connect
to its grid. This specification of battery
was set based on the results of the
Mega Solar project in Wakkanai. In this
section, the NEDO demonstrations
from 2000 are explained.
Based on the discussion of
reducing fluctuation of wind power by
battery, NEDO commenced a wind
power stabilization technology development project in 2003.
In this project, a redox-flow battery
system (6,000 kW-6,000 kWh) was
installed at Tomamae Winvilla Park
(30 MW) in Hokkaido, Japan (Figure 3).
At the demonstration site, the firstorder time lag control methods and
the reliability of battery storage system were examined to reduce shortterm fluctuation in wind power.
The PV system operates during the
daytime when the demand of the
power system is high; therefore,
balancing is not a serious for PV issue
as wind power may operate in low
demand periods like nighttime.

However, it is easy to estimate that
balancing problems will occur when
the PV system spreads widely. NEDO
also started the demonstrative project
on technologies for connecting largescale PV power plants to transmission
systems (FY 2006-2010) in which the
output from a large-scale PV power
station would be controlled during
certain time periods through the use
of batteries. In this project, 5 MW of
PVs was installed in Wakkanai City,
Japan (Figure 4), Hokkaido, and a
2-MW PV was installed in Hokuto
City, Yamanashi Prefecture, Japan. At
those sites, several grid-stabilizing
technologies were tested by connecting mega solar power systems to the
utility transmission system.
In the Wakkanai site, the system
was designed to identify methods to
reduce the negative impacts of renewable energy by balancing power
systems and stabilizing frequency by
using storage. For this purpose, a sodium-sulfur (NaS) battery (1.5 MW-
12 MWh) was introduced. Using this

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Table of Contents for the Digital Edition of IEEE Electrification Magazine - September 2015