Photovoltaics mounted directly on the ground promise extremely cheap electricity

The US startup Erthos is convinced that by dispensing with conventional assembly systems and laying flat modules only with wires to hold them in place, it can reduce electricity production costs by more than 20%.

The considerations apply not only to open-air systems, but also to flat roofs and, to a certain extent, to bodies of water.

Two factors are often underestimated for photovoltaic systems in warm and dusty regions: Soiling and temperature. Erthos wants to minimize the soiling with a cleaning robot and thus compensate for the poor temperature coefficient. This of course also applies to roofs in cities, which often suffer enormous yield losses due to pollution.

A steeper incline and a direct orientation towards the south does not necessarily lead to an increase in yield, since in summer the losses due to modules that are too warm are enormous . In terms of electricity yield, vertically mounted modules with a high albedo are of course ideal, such as mirrors or glass balls in color or bright flower meadows, but both mirrors and modules in urban environments must be cleaned regularly in order to secure the yield in the long term. See also my soiling calculator on photovoltaics.

Of course, we have to take into account in the discussion that we are assuming a Californian start-up that is relocating the modules to a desert floor, where not much grows without irrigation. The principle also applies to modules and mirrors laid on the water, as these also quickly become dirty and have to be cleaned.

However, if we lay mirrors between the rows of modules, the field could always be optimally cooled, as a robot cleans the mirrors and mirrors reflect the heat very well into space.

Perhaps we will soon see mirrors laid on the ground in dry areas and cleaned by robots in order to cool entire fields. According to the FAO, light-colored plastic mulch films have already become necessary for cooling many fields, as the Plastic in Agriculture Report writes.

What we should also consider before we criticize thermal adaptation strategies (SRM), cooler soils emit significantly less CO2 and methane than soils that are much too warm. But this technology is also interesting for landfills that need sealing.


Do you know how much money you can lose per year, if you do not clean your solar system on a regular basis?

Cleaning plants brings cash

Soiling Calulator
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Pollution of your plant can take you up tolose per year::

Contact me for an offer on cleaning – yield benchmarking and matching sensors optional according to the IEC:16724:


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