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BI PV Urban Scale Project Details
Name projectHazama-so
Year2000-00-00 (Start operation date)
PV applicationFlat roof - mounted & mechanical fixing
PV power total kWp
LocationNagoya, Aichi
Latitude/Longitude35°10'26"N 136°58'19"E
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Project summary
Nagoya city is the fourth biggest city in Japan and with over 2 million inhabitants. In this project (reconstruction of an old district in the nineties) 8 new buildings were equipped with PV systems on the roof and completed in 2000. The capacity of the PV system of each building was different, wiht 203kWp of PV installed in total.

Urban scale PV aspects
The city government is promoting the installation of PV systems on municipal dwelling houses in their environmental action plan. Hazama-so is one of the municipal dwelling houses (apartment buildings). Because the buildings were built in 1955 and 40 years old, it was decided to reconstruct the buildings in the mid- 90’s. Afterward, according to their environmental action plan, it was decided to install PV systems onto the new buildings. The work of reconstruction started in 1998 and 8 new buildings, equipped with PV systems on the roof, were completed in 2000. The project to reconstruct the buildings with installing PV systems was approved as a symbiosis housing urban area development model project, which was applied to environmental-conscious housing construction project implemented by local public organizations.

Special PV project info
PV architecture and building integrationSince the decision to install PV system was after the development of the buildings’ reconstruction plan, the domestic wiring design for the buildings was changed for PV system installation. BOS like inverters were put in a cubicle placed on the roof of the buildings. PV arrays were mounted and mechanically-fixed to the roof.
Urban planning issuesRefurbishment of an old housing district with PV on new buildings! To maximize PV electric output, the inclination angle of the PV arrays was 20 degrees facing south.
Economical and financial issuesBecause the project was approved as a symbiosis housing urban area development model project, one-third of total project cost including PV systems was subsidized by the national government. After starting operation, a net-metering scheme was applied so that surplus PV is traded between the inhabitant and the utility company, at the same price of the residential electric tariff.
PV ownershipBuilding owner: Nagoya city government. PV owner: Nagoya city government. PV energy user: Nagoya city government.
Tariffs and metering
Info on grid issuesWiring from PV systems is connected with a low-voltage circuit of the buildings and the electricity is supplied for common use such as corridor lights, lift, etc. To connect with the low-voltage circuit, 5kW inverters were used. The result was many inverters in a limited site and a maximum of 6 inverters were installed per building. To avoid negative influences against a grid network, an operation test on function of backflow operation was conducted in the presence of a utility company (Chubu Electric Power corporation) and it was recognized there would be no problems on the issue.
Other infoWhen the amount of PV system electricity over the demand of the common loads for the building, reverse power flow to the grid occurs. However, because dwelling units in the building demand electricity, the surplus electricity would be supplied for the dwelling units and not other grid customers. Therefore, an over-voltage phenomenon is not a concern. Since starting operation, there are no PV system grid-connection problems.
Remarks and recommended readingIn cooperation with: Mitsubishi Electric corporation. Besides the Hazama-so project, Nagoya city government is promoting to install PV systems onto other municipal dwelling houses (apartment buildings) and their activities for environmental protection are widely recognized. Hazama-so is located in Chigusadai area in Nagoya city. A junior high school is there in Chigusadai area, also with a PV system.

Other project data
Type of projectCommercial project
Other relevant aspects
Start of PV project
Start operation PV system2000-00-00
Main project leading companyNagoya city government
Main project contact person
Contact email
Contact address
Includes PV database projects

Urban district data
Kind of urban areaResidential - urban
Main building typesHouses - multi-story apartment building
New/Retrofit/AddedNew building integration
Main PV area address

PV systems
PV applicationFlat roof - mounted & mechanical fixing
PV power total urban project203 kWp
Number of dwellings/units8
PV power per dwellings/units0 kWp
Main PV system typesGrid-connected - demand side
Main PV module typesFramed - regular module
Main PV cell typesCrystalline silicon - multi
PV module brand and typeMitsubishi Electric corporation
PV inverter brand and typeMitsubishi Electric corporation

PV cost and energy production
Total PV system investment
Average PV modules only costs
Total PV energy yield214996 kWh Calculated
PV energy user owner

Projects website
Other websites
Webpage Educational Tool

1. Hazama-so.pdf (language: English)

(bipv) building integrated pv