An Italian research group has evaluated the advantages of combining solar electricity and vertical farming in greenhouses. Scientists claim that this new approach provides better land use while increasing agricultural yields.
They defined solar greenhouses as “closed agrivoltaics (CA), which would be a type of agricultural project where electricity production and food production are carried out in a protected environment.
“All common garden plants grow without or with limited yield losses when the reflection percentage of the rooftop solar panels into the greenhouse area (PV coverage ratio) is less than 20 percent,” the researchers elaborated. “We propose an alternative approach to increase the sustainability of CA agriculture through the experimental integration of vertical farm (VF) technology, which is characterized by consistently higher yields, light and resource use efficiency than conventional greenhouses.”
They also emphasized that light-emitting diodes (LEDs) are used in vertical farming to achieve high photosynthetic utilization efficiency and year-round production in the plants. They emphasized that solar power is the perfect solution to reduce the impact of the high energy consumption of LEDs on projects. viability.
The Italian team aimed to assess in particular the country’s productivity, the solar electricity sector and the electricity required by the experimental VFCA system, which has a coverage rate of 100%. “Yield was determined on green and red baby leaf lettuce cultivars using four light treatments, expressed as Daily Light Integral (DLI) and compared to control CA,” it explained.
They tested this approach on an experimental 40.48 kW VFCA located in the municipality of Villaperuccio, Sardinia, Italy. The system has been operating since 2012 and sells electricity to the grid at a feed-in tariff of €0.39 (€41.78) per kWh. The shelves used in vertical cultivation are each 40 cm high and have eight dimmable LED lamps, each with a nominal power of 22 W.
There are four varieties of lettuce in the greenhouse, which have been grown with four different light treatments.
Through their analysis, the researchers found that the VFCA system can provide 13% higher agricultural yield compared to the traditional CA system with CO2.2 emissions fall by more than 12 percent.
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“The case study measured the high land consumption of this conversion, whereby the CA area was 5.4-13.9 times larger than the VF area to achieve energy self-sufficiency and avoid the associated CO emission.2 emissions, i.e., only 7-18% of the CA area can be returned to vertical farming,” they emphasized.
Their findings were presented in the study “Increasing the agricultural sustainability of closed agroelectric systems by integrating vertical farming: A case study of baby leaf lettuce, published Applied energy. “This study helped to identify key design features for converting existing and underutilized CAs into sustainable and efficient mixed farms,” the researchers concluded.