The term removable rarely applies to solar panels, which are generally designed to be permanently fixed. Yet at Sun-Ways, it's a key feature. The panels must not only withstand the passage of trains, but also be able to be quickly removed to allow for heavy maintenance operations on the tracks, such as grinding rails or tamping ballast —otherwise, they risk being damaged.
Operating the Sun-Ways system does, of course, come at a cost, but since the process is mechanized, this cost is perfectly manageable and can be included in the overall cost of an installation. At this stage of our development, the average cost per kWh produced is around CHF 0.10.
The electricity produced can be used in three ways: supplying low-voltage rail infrastructure (switches, signals, stations), re-injecting it into the local distribution network, or directly injecting it into the train traction network. This last option, perfectly suited to Sun-Ways' mechanized concept, avoids the need for ground-based inverters and allows for recovery via existing substations.
Ultimately, the risks are comparable to those of a solar power plant installed on a roof or a noise barrier. Although Sun-Ways uses standard panels, they are pre-assembled in the workshop with specific fasteners that require special tools for disassembly. In addition, unique markings on each panel greatly limit the risk of theft.
Dirty panels produce less electricity, a phenomenon also well known on the roofs of houses or in the desert. However, for panels installed between the rails, automated cleaning systems exist: a cylindrical brush placed at the end of the train cleans the panels as the train passes. This device guarantees maximum panel performance at minimal cost.
Obviously, panels covered in snow cannot produce electricity, especially since in our case they are laid flat. However, this problem deserves to be put into perspective, because in winter, even for power plants on sloping roofs, production is minimal from November to February.
The Sun-Ways suspension system applies force to each rail, and its design gives the system great stability. According to an expert report, the Sun-Ways system remains perfectly stable when trains pass over it at speeds of up to 150 km/h and can withstand winds of up to 240 km/h. On the section chosen for the pilot project, the maximum speed is 70 km/h.
The use of "Full Black" panels equipped with an anti-reflective filter helps minimize this risk. In addition, for each Sun-Ways installation project, a glare analysis is systematically carried out, in accordance with practices already in force for ground-mounted power plants located near railways.
The standard photovoltaic panels used with Sun-Ways devices, installed between the rails of a "normal" 1435 mm gauge track, measure approximately 1000 mm × 1700 mm. However, the size of the panels can vary depending on the track gauge, and the Sun-Ways device adapts accordingly.