Creating greenhouses with tinted semi-transparent PV modules could result in gross financial gains of 2.5% for basil and 35% for spinach as project owners could ramp up their financial gains by harvesting crops and generating solar power from the same land.
Researchers from the University of Cambridge described the potential gains in “Tinted semi-transparent solar panels allow concurrent production of crops and electricity on the same cropland,” which was recently published in Advanced Energy Materials.
Deploying bifacial modules above crops in greenhouses to harvest biomass and electricity from the same land has been done before. The cells and modules are usually further apart, allowing more sunlight to penetrate and reach the crops.
However, shadows from opaque modules on crops cannot be avoided, and biomass growth falls in such applications.
New research suggests that using tinted semi-transparent modules could lead to better results.
Polysolar, a Taiwan-based manufacturer of 20% transparent solar glass, has supplied the research modules. The thin‐film amorphous silicon modules have a transparent zinc oxide back conductive layer and clear front glass coated with fluorine tin oxide.
The photovoltaic area of the modules is laminated in between two sheets of glass. According to the research paper the modules prompt 8% conversion efficiency and thus have an output of 66 W m−2.
The thinking behind using tinted modules is that plants and solar PV require light, but of a different wavelength and quantity.
Using bespoke orange-tinted panels, the wavelength shining onto the crops inside the greenhouse is the one that is most productive for plants.
Researchers have matched the tinting of semi-transparent PV modules with the bandwidth of light that plants absorb for photosynthesis. A promising trial with basil and spinach has opened up economic opportunities for farmers.
Reference- PV Magazine, Polysolar website, Advanced Energy Materials