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BI PV Urban Scale Project Details
Name projectSolbyen
Year1997-00-00 (Start operation date)
PV applicationInclined roof - mounted
PV power total kWp
LocationRing Sø, Brædstrup
Latitude/Longitude55°57'58"N 9°36'13"E
© EnergiMidt

Project summary
The SUN CITY is located in Ring Sø on the outskirts of Brædstrup. Since its commissioning in the summer of 1997, residents on the 30 houses with PV modules on the roofs have changed their habits of power consumption significantly. At the same time, it has been found that the PV systems produce more electricity than expected, and that they do not affect voltage quality in the electricity grid.

Urban scale PV aspects
The PV arrays occupy 10, 20 and 30 m2 respectively. Twenty-seven installations are on slanted roofs, one is installed on a vertical house wall, and two are situated on flat garage roofs. The installations are placed on existing buildings, designed without regard for the optimal placing of PV modules, that's facing south at an angle of 42 degrees.

Special PV project info
PV architecture and building integrationAn architect participated in the planning of the PV arrays.
Urban planning issuesBut none of the SUN CITY's houses meet the optimal requirements for the placing of PV arrays. Individual houses even have angles of up to 60 degrees to the south. Despite the generally non optimal options for placing the PV installations, the readings show that the PV systems are extremely productive. On installations orientated at 60 degrees to the south, only 10% reduction is found relative to the optimum electricity generation. All units have thus lived up to expectations, and in the periods with most sunlight, individual units have even covered the entire consumption in each house.
Economical and financial issuesOne of the factors which make the practical use of PV-generated electricity difficult is that many families in the SUN CITY work away from home during daylight hours, when the PV plants generate the most electricity. The project has shown that half of the PV electricity cannot be used in the SUN CITY when produced, and is therefore sold to the electricity grid. At the beginning of the project, there were price differences between purchase and sale of electricity to the grid. But the project has been a factor in the Danish parliament's changing of the tariffs for a trial period, so that producers of PV electricity may store their electricity without charge in the grid (net metering).
PV ownershipBuilding owner: Inhabitant PV owner: Inhabitant PV energy user: Inhabitant
Tariffs and metering
Info on grid issuesThe project also investigates whether the electricity generated in the SUN CITY affects the power quality of the electricity grid. The question was whether the electricity produced by the PV system would reduce the general power-quality on the grid. But no changes in the power quality were noted in the grid, and the PV systems' irregular electricity production has had no negative influence.
Other infoTo investigate consumer behaviour during the project, data on each family’s electricity consumption were collected in the months before the installation of the PV systems. Against this background, an average reduction of 4,5 % in the SUN CITY families' electricity consumption was found. It is noteworthy that the savings were achieved by altering consumption patterns. Only a few households bought energy-saving household appliances during the period in question. Many households say that the newly developed »PV meter« has been a factor in drawing attention to electricity consumption, thus paving the way for savings. Neither did the residents of the SUN CITY compromise their comfort to save electricity. In 2006 ten years after the project was started we can still see the added value in terms of energy savings, the households is still using 5-10% less energy than a reference group.
Remarks and recommended readingNew Retrofit Added: Retrofit - building integration & Added separately to the buildings. Energy yield per year: 800 kWh/kW. Other project company: Knudsen og Halling, Velux.

Other project data
Type of project
Other relevant aspects
Start of PV project
Start operation PV system1997-00-00
Main project leading companyEnergiMidt
Main project contact person
Contact email
Contact addressSøndergade 27, 8740 Brædstrup, Denmark
Includes PV database projects

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

PV systems
PV applicationInclined roof - mounted
PV power total urban project60 kWp
Number of dwellings/units30
PV power per dwellings/units1 kWp
Main PV system typesGrid-connected - demand side
Main PV module typesFramed - regular module
Main PV cell typesCrystalline silicon - multi
PV module brand and typeSolarex/MSX 53
PV inverter brand and typeSAM/SWR700

PV cost and energy production
Total PV system investment8 Euro
Average PV modules only costs
Total PV energy yield0 kWh
PV energy user owner

Projects websitewww.energimidt.dk
Other websites
Webpage Educational Tool

1. Solbyen.pdf (language: English)

(bipv) building integrated pv