The prerequisites for a photovoltaic facility on the waste site are its stability and preservation of the surface sealing. Therefore, the city of Fuerth commissioned a geotechnical survey in Dec. 2000 and this in turn, brought the proof that the construc­tion of a photovoltaic facility was possible. A supplementary report from October 02, which referred to a total area coverage of 1.7 ha, came to the conclusion “that the stability and serviceability of the waste site’s surface sealing is suitable for the current planning.”

Finally, the same conclusion was also reached in an inspection report by the Nurnberg Office of Regional Industry within the framework of the Construction Licensing Procedure.

Constructional set-up and soil protection

The PV-installation encompasses approx. 5,600 solar cells from the company Sharp. Eighteen solar cells are mounted to each module table which is then anchored into the ground. Approx. 350 module tables were mounted on the south slope of the waste site. The determined layout of the foundations was calculated so that a snow load of 75Kg per square metre could be carried. For secure hold against arising wind drag, the foundations were calculated by a 1:5 safety ratio. The material chosen for the substructure was hot galvanized steel.

To convert the direct current generated by the solar modules into conventional net­work, alternating current, central current converters from the company Siemens are used which are built at the work in Fuerth. A maintenance contract guarantees the electricity input for a 20 year period.

The following preventative measures were met in order to counter potential soil ero­sion:

■ The module surface of the photovoltaic-installation will not be constructed as a continuous, closed surface; a loose superstructure is planned.

■ Maintenance paths go vertically from the bottom to the top area of the photo­voltaic-installation; a strip of width 1.6 metres will remain between each verti­cally aligned row of modules.

■ A distance of at least 5 centimetres will be kept between the module tables in a row.

■ The module table does not have a continuous, closed surface; each module is drained via gaps between the individual cells, thereby distributing rainwater extensively.

■ The loose “superstructure” of the waste site’s surface and the height of 1.5 metres from the solar module to the ground, lets sufficient diffused light reach
the ground surface under the modules; this also allows a layer of vegetation under the modules which acts to prevent erosion.

■ In addition, a grass/herb-seed mixture especially for shady locations is used.

■ Sheep grazing is planned in caring for the vegetation; if necessary, the mechanical cutting of the areas under and between the modules is possible.