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BI PV Urban Scale Project Details
Name projectSekisui Harmonate-town Shin-Kamagaya
Year2004-00-00 (Start operation date)
PV applicationInclined roof - mounted,
Inclined roof - integrated: PV roof tiles,
Flat roof - mounted & mechanical fixing
PV power total kWp
LocationKamagaya, Chiba
Latitude/Longitude35°46'32"N 139°59'49"E
© Sekisui Chemical Co., Ltd.

Project summary
Sekisui Harmonate-town Shin-Kamagaya is located in the west of Chiba prefecture and is 40 minutes from the center of Tokyo. The development area is 6 500 m2 in total. A concept of developing the area was ‘A house living with sun & a town living with future’ and all houses were equipped with PV systems. On this area a small PV community has been realized, consisting of 29 house compartments. Each house is equipped with a 3 kWp rooftop.

Urban scale PV aspects
Generally, an approach for symbiosis housing in the suburb is to have a green area in a large site and to build a house in a low building-to-land rate. However, because the site is an existing urban area near city center, to design a large compartment was difficult from an economical viewpoint. Therefore, to develop an urban-type symbiosis housing equipped with facilities for energy conservation and creation was decided. An effective utilization of building roof area was very important and to install PV systems on all houses was decided. The houses achieved the energy conservation standards for houses and were all-electric. Further, electric power lines were laid underground in the area. One of the important factors to realize and succeed the project was to obtain a positive support by the utility company.

Special PV project info
PV architecture and building integrationTo begin with the project, compartments before building houses were sold with carrying option to build an all-electric house equipped with PV system. Then, each house was designed and built on the compartment according to users’ (inhabitants’) intention. Two kinds of the roof-type are there; one is inclined-roof and the other is flat-roof. In case of inclined-roof, PV modules were mounted in the angle of inclination of the roof. In case of flat-roof, PV modules were fixed with support structure in the angle of 10 degree because of an effective utilization of roof area.
Urban planning issuesAlso, because the electric power lines were laid underground, an open environment was created in the area.
Economical and financial issuesThe PV system received a governmental subsidy, available through Japan’s residential PV program. 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. For the all-electric house, electricity tariff structure is different than usual. The daytime rate is higher, while in nighttime the tariff is discounted. This means the value of the PV electricity from inhabitant to the utility company is higher. Additional significant energy bill reductions resulted from energy conservation measures of high thermal insulation and high efficiency equipment.
PV ownershipBuilding owner: Inhabitant. PV owner: Inhabitant. PV energy user: Inhabitant.
Tariffs and metering
Info on grid issuesThere was concern for over-voltage phenomenon caused by a concentrated PV systems in a limited area. In addition, supplying electricity to the area where lots of all-electric houses would be constructed should be the most important issue for a utility company. Therefore, the electricity distribution line in the area, including countermeasures for the concentrated PV systems installation was designed and constructed by the utility company (the Tokyo Electric Power Company). As a result, one transformer was set for two houses, e.g. two PV systems.
Other infoIn addition to thermal insulation performance satisfying the energy conservation standards, all-electric houses were standardized. Not only PV system but also a high-efficiency electric water heater, called “Eco-Cute”, was equipped in all houses. These advanced facilities caused high price of the houses, however the added value of the houses and the community has highly-regarded property value. As well as each inhabitant’s environmental consciousness, it is expected the extensive consciousness and actions for environment as a community will be developed.
Remarks and recommended readingEnergy yield per year: 1 000 kWh/kW/year (calculated). Sekisui Chemical Co., Ltd.: Tel: +81-3-5521-0575 FAX: +81-3-5521-0597

Other project data
Type of projectCommercial project
Other relevant aspects
Start of PV project
Start operation PV system2004-00-00
Main project leading companySekisui Chemical Co., Ltd.
Main project contact person
Contact email
Contact addressSekisui Chemical Co., Ltd., Minato-ku, Tokyo, 105-8450, Japan
Includes PV database projects

Urban district data
Kind of urban areaResidential - urban
Main building typesHouses - single house
New/Retrofit/AddedNew building integration
Main PV area address

PV systems
PV applicationInclined roof - mounted,
Inclined roof - integrated: PV roof tiles,
Flat roof - mounted & mechanical fixing
PV power total urban project90 kWp
Number of dwellings/units29
PV power per dwellings/units3 kWp
Main PV system typesGrid-connected - demand side
Main PV module typesFramed - regular module,
PV building elements - PV roof tile
Main PV cell typesCrystalline silicon - multi,
Crystalline silicon - mono,
Amorphous silicon
PV module brand and typeSharp corporation (28) & Kaneka corporation (1)
PV inverter brand and typeSharp corporation (28) & Omron corporation (1)

PV cost and energy production
Total PV system investment500000 Euro
Average PV modules only costs
Total PV energy yield0 kWh
PV energy user owner

Projects website
Other websites
Webpage Educational Tool

1. SekisuiHarmonate-townShin-Kamagaya.pdf (language: English)

(bipv) building integrated pv, (PV) rooftops