For photosynthesis, plants use light waves from only a portion of the spectrum, the remainder of which can be recovered and used to generate solar power. This is the idea used by solar modules developed by EPFL startup Voltiris.
With encouraging preliminary results, a pilot installation of the solar module recently set up in Graubunden.
In the cold climes of Switzerland, cultivating tomatoes, cucumbers, peppers and other heat and light-intensive vegetables requires a greenhouse – but it consumes huge amount of energy. Farmers need to balance crop yield and economics with environmental factors. By numbers, it costs more than 1.5 million CHF a year to heat a greenhouse of 5 hectare. “And CO2 emission from a greenhouse of this size is the same as that from 2,000 people.”
In order to address this, The Swiss association of fruit & vegetable growers has set a target to eliminate all hydrocarbon-based energy from its farming operations by 2040.
Importantly, the system developed by Voltiris can serve to be valuable to attain this goal. The technology of the system is based on the fact that plants don’t use the complete spectrum of sunlight, the remaining spectrum can be concentrated on photovoltaic cells to produce solar power.
In terms of structural specification, Voltiris’ system is lightweight and is designed to follow the sun’s course across the sky to record daily yield at par with traditional solar panels. The first batch of vegetables cultivated using Voltiris system were harvested from pilot test of the system at two greenhouses at Valais and Graubunden.
In fact, sunlight is essential not only for growing crops, but also phototropism. But plants are selective about the portion of the spectrum which is used, relying on blue and red light.