Innovation for Cool Earth Forum 2020
Advancements in Digital and Energy Technologies

Utilization of Demand Side
Resources for Energy Efficiency andDemand Response in Japan
Yumiko IWAFUNE
Energy System Integration，Social Cooperation Program (ESI)
Institute of Industrial Science(IIS)The University of Tokyo

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Introduction• Flexible distributed energy resources (DERs) on
demand side will contribute to stable powersystem operation including massive renewableenergy.
• Small DERs in Japan– Heat pump water heaters (HPWH) (1-1.5 kW)– Electric vehicle batteries (EV) (40-60kWh,3-6kW)– Residential stationary storage batteries (-10kWh,35kW)• A number of VPP (virtual power plant)
demonstration project to bundle these small
resources are currently ongoing in variouslocations.
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How many DERs are available in Japan?
• Heat pump water heaters (HPWH)– Cumulative sales were over 7 million units in 2018. (Government target in2030 is 14 million units)– Existing equipment is operated during the late night and early morning hours
when electricity rates are low and cannot be remotely controlled. Some ofnew products can be controlled.

• Residential stationary batteries (SB)– Cumulative sales were 360 thousand units in 2019.
– They are increasing rapidly due to recent disasters such as typhoons.
– Many are being operated independently, but are slowly beginning to be
remotely controlled.

• Electric vehicles (EV)– Cumulative installation of pure battery EV (BEV) and plug-in EV (PHEV) was
240 thousand units (2018). (Government target in 2030 is 9 million units)– Hybrid vehicles are driving the sales of electric vehicles in Japan. Regarding
BEVs and PHEVs, the number of sales has peaked because the number oftypes of vehicles is limited.
– A demonstration on market price-linked charging was launched this year.
– The use of charge and discharge control is limited due to the high price of V2X
devices (bi-directional charging system).

• Household number in Japan : approx. 50 million

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EnergyEnergy
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about 15 GW of flexible power
resources• HPWH– Demand response effect of avoiding
PV output curtailment are provided.
– HPWH operates primarily during theday when solar radiation is high,which saves electricity consumption
due to high outside temperaturesand reduced tank loss.

• EV– The value of battery use is low if
only charge control is used becauseof a short driving range in Japan– Charge and discharge control
increases the value of batteries.

Demand (GWh/h)

How much is the potential of DERs as a flexible resource?
140120100806040200135EV

7911 13 15 17 19 21 23Curtailment

HPOriginal load

Net load

Adjusted net load

Supply and demand simulation on April 1,2030(PV 103GW, wind power 32GW installed)
DR effect of EV 9 million units and HPWH
14 million units in Japan

Iwafune et al.

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Miyakojima Island Smart Community Demonstration
Project• Group control of controllable loads such as HPWHs and batteries toimprove the load factor of the power system and absorb PV surplus under
the limited conditions of an island.
• A business model based on a third-party ownership model for HPWHs andstorage batteries.
• Construction of a cloud-based control system while avoiding increasing
communication and management costs.

• FY 2018-19 PV+HPWH implementation results: 202 units in 40 municipal
housing units, and 10 welfare facilities.
SummerWinter

PV Curtailment
Residential PV

PV Curtailment
Residential PV

PV generation

PV generation
HPWH load

HPWH load

HPWH shifts boiling operation.

5EnergyEnergy
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• But the barriers are also high.
– The small unit capacity of the resource makes it
difficult to control them cost-effectively.
– To break the barriers….
• Spread of DER devices• Building an aggregation system using digital technologies• Further reduction of communication and control costs• Market design for the value of these resources to berealized• Construction of grid cord for DERs

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