Envirodesk (Belgium), July 31, 2008

Within the scope of the European research project PV-UPSCALE, researchers at the Fraunhofer Institute for Solar Energy Systems ISE have compiled two reports that show how municipal electricity grids can accept large amounts of photovoltaic electricity. A working group of ten institutes from seven countries developed, in addition, a comprehensive online-portal for the integration of photovoltaic (PV) systems in urban settlements and buildings, including a database with exemplary systems: www.pvupscale.org.

"The existing municipal electricity grids can also accept greatly expanding amounts of solar electricity," says Hermann Laukamp from Fraunhofer ISE, project leader for the working group "Grid Issues." "The capacity of the grid for decentralized feed-in can be appreciably increased through non-investment-related measures." Detailed information for energy industry can be found in the reports "Recommendations for utilities on PV system interconnection" and "Impact of photovoltaic generation on power quality in high PV density real estate areas" located on the homepage of the project, which ended on 30 June 2008 after a two and half year duration.

In addition to the grid connection, the European researchers investigated three other topics: In a data bank, which includes the countries who participated in the project as well as other countries in the International Energy Agency IEA, attractive examples for building integrated photovoltaic systems are documented with photos. One working group investigated photovoltaics with respect to urban planning aspects while another group concentrated on the economic aspects. Free, detailed information for architects, planners, municipal communes and the energy industry can be found at: www.pvupscale.org.

Adjusting the low voltage transformers which supply electricity to the households within each district is one example of how the capacity of the existing electricity grid can be increased without investments. Often, for example, the output voltage is set at 236V instead of 230V to allow for reserves. Today, however, photovoltaic systems bring local voltage increases with them. If the maximum allowable value is exceeded due to these increases, then the system can not be connected. If the service technicians decrease the output voltage setting by 1-2% during their routine maintenance rounds, then the problem is solved!

When comparing different countries, the researchers found that the German energy industry is more active and flexible with regard to solar electricity than many of their European colleagues. "Often strict regulations and bureaucracy stand in the way. In Germany, photovoltaics already belongs to the standard repertoire of the energy industry," says Laukamp.

The bottom line of the project is: When photovoltaics contributes, as aspired by politics, an increasingly larger fraction to the electricity supply grid, the grids in the urban areas can accept the additional electricity. "Where there is a large load, there is room for large amounts of solar energy," explains Laukamp. "In rural areas, there is still need for investigations."

From 1 Jan. 2006 through 30 June 2008, the project PV-UPSCALE was carried out to investigate the large-scale integration of photovoltaics in European cities. The project was sponsored by the Intelligent Energy - Europe Programme of the European Union. Project partners from Germany included the Fraunhofer Institute for Solar Energy Systems ISE, the consulting company Ecofys, and the energy supplier MVV Energie AG. Other project partners were from Holland, Austria, France, Spain and Great Britain.