Project Subjects
Evaluation of Demand Response Programs
Background and Objective
The electric utility in Japan has been tackling with various load leveling measures such as time-of-use(TOU) rates or contracts for adjustment to peak demand using thermal storage air conditioners. On the other hand,the “Demand Response (DR) program,” which encourages voluntary energy conservation or load leveling on thedemand side by using the Energy Management Systems (EMS), has been operated recently in the U.S., and its
further expansion is expected to be the main service of the smart grid.
In this project, we clariﬁed the effects of applying the DR program in Japan on peak demand saving ofeach customer and utility-wide load and supply cost. Also, a prototype of energy management system to verify
the effects of DR program will be developed.

Main results
1. Issues in assessing the beneﬁt of smart meters in Japan based on the analysis of the U.S. caseTo ﬁnd issues in assessing the social beneﬁts of smart meters in Japan, we surveyed and analyzed literatures on the smart meters and smart grid in the U.S. According to our analysis, the smart meters in the U.S.
are expected not only to dissolve lack of supply capability and improve supply reliability, but also to enable thegrid connection of renewable energy resources and improve energy conservation (Table 1). These social beneﬁts
might be important for Japan as well; however the effectiveness of smart meters to the objectives has not beenclariﬁed in Japan. Beneﬁts of demand response (DR) programs using the smart meter in Japan are to be demonstrated by ﬁeld tests. In addition, alternatives to the smart meter should be also assessed in order to achieve proper
control of surplus electricity from photovoltaic (PV) power in the future and in visualization of electricity usage
for customers [Y09028].
2. Preliminary ﬁeld experiment of demand response control in a Japanese ofﬁce space
Customer acceptance is an important factor to determine the market potential of demand response program. To study the acceptance, we conducted a preliminary ﬁeld experiment of peak-cutting demand responsecontrol of air conditioning and lighting in an ofﬁce space located in Tokyo during 2009 summer. The target equipments were controlled on event days when forecasted daily highest temperature exceeded 30 degrees Celsius.
Electricity consumption of the controlled equipment, thermal environment of the controlled space and worker
comfort were surveyed to investigate the DR control effect.
We adopted two kinds of DR control strategies in the experiment, named event-U and event-K. In thelatter, some lights in the ofﬁce space were turned off and air conditioners were stopped for a longer time than theformer. In these two DR control strategies, the experiment results showed a reduction of about 10% and 23% ofpeak demand of ofﬁce space during DR period (Table 2, Fig. 1), respectively; however, the adopted DR control
strategies affected worker comfort and their subjective working efﬁciency (Table 2) [Y09014].

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Environmental and Energy Utilization Technology
Table 1

Current situations and issues in social beneﬁts of smart meters, which are expected in
the U.S. and Japan

Expectations for smart meteringin the U.S.

Current situations and issues associated with smart
metering in Japan①Eliminate lack ofsupply capabilityReducing peak demand can beachieved by introduction of DR
program, visualization systemsof power usage and distributed
generators, as a result, whichmakes it possible to postpone a
new power plant construction.

Although lack of supply capability will not occur in thelong term, there might exist inhibition risks of stable powersupply (e.g. deterioration of energy situation). In addition,
further improvement of load factor might be possible.
Therefore load management would be needed in Japan.
Although load management by use of smart meters ispossible, its effectiveness has not been clarified in Japan.

②Improvement ofpower supply
reliability

If a power blackouts occurs, grid
operators can detect abnormality
quickly from monitoring information of smart meters andrestore the failure. It is also
possible to avoid rolling blackoutby reducing peak demand.

High supply reliability and high power quality have been
maintained with distribution automation systems in Japan.
Although introduction of smart meters might contribute todetect and restore the low-voltage power line failures
quickly, its effectiveness should be measured quantitatively.

Introduction of smart meters
makes it possible that a large
amount of renewable energy
resources and EVs/PHEVs interconnect with the power grid.

If a large amount of PV generators connect with grid, a few
damages to grid stability are suspected. In particular,
surplus electricity from the PV generators is concerned.
There exist that a method which utility send inhibitory
signals to power conditioning subsystems of PV generator
via smart meter to avoid the surplus electricity, but there
also exit alternatives to the smart meter should be assessed.

It is possible to visualize powerusage and control intelligent
devices by use of smart meters,
as a result, which is expected toencourage consumers to use
energy more efficiently.

Efforts to achieve energy-conservation are absolutely
imperative for Japan where natural resources are scarce.
Although achieving energy-conservation by visualization ofelectricity usage using smart meter is possible, alternatives
to the smart meter should also be assessed.

③Enabling the gridconnection ofrenewable energy
resources andEVs/ PHEVs④Energyconservation

Table 2 Summary of DR Control Experiment
The shorter the running period of air conditioners, thelarger the amount of shaved peak demand, and the worse
the subjective working efﬁciency of ofﬁce workers.
Name of DR event

Proxy-event

Event-U
Event-K
All of air
All of airconditioners
No control conditioners
Air(All air
turn off for 5 turn off for 5
Conditioner
conditioner minutes and minutes and*2Control
turned on) then turn on then turn on
DR1for 10 minutes for 5 minutes
control targets*
strategy
A part of lights
in theLight
No control
No control
perimeter turnoff
Number of event days6 days
6 days4 daysPeak cut ratio
10%
23%0.48
0.70.86
PMV *4Results
Subjective working
81%
73%
49%
efficiency *3* 1 : DR period on event day is 13:00-16:00* 2 : Preset temperature is fixed to 26 degrees C when air conditioners turn on* 3 : Percent of workers who stated that thermal environment of controlled
space does not affect their working efficiency* 4 : Predicted Mean Vote

Electricity Consumption (kW)Social benefit

403530Air Conditioner(Compressor)

2520

Light

Air Conditioner

1510DR period

508910 11 12 13 14 15 16 17 18
Estimated Baseline (detailed bottom-up)
Estimated Baseline (simple regression)
Actual Load

19 20
Hour

Fig. 1 Estimated shaved peak demandon an event day with Event-K
The contribution of air conditioning appliances to electricity demand reduction is prevalent during the controlled
time.

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