Agri-Photovoltaics is an emerging form of agriculture that not only solves the problem of power supply needed to power water and irrigation machinery, avoiding competition between the PV industry and agriculture for land, but also allows the extra electricity to be sold to the national grid. PV projects can be installed in a variety of agricultural scenarios, and the following are some examples of PV greenhouse applications that we have compiled.
In some European countries where current regulations prohibit the installation of ground-mounted PV systems in agricultural areas, PV greenhouses are seen as a solution to bypass the current regulations. By installing PV systems on the roof or walls of the greenhouse, it is possible to achieve the dual benefits of food and energy production on the same piece of land. Photovoltaics can provide the energy needed to run the greenhouses and can increase farmers’ incomes, bringing multi-sectoral development to rural areas. In addition, PV greenhouses are highly competitive for agricultural production in ecologically fragile and remote areas.
Current status of photovoltaic greenhouse research
The Netherlands
The Netherlands is one of the world’s leading countries in greenhouse cultivation, and according to incomplete statistics, there are currently about 10,000 hm2 of glass greenhouses in the Netherlands, accounting for 1/4 of the total area of greenhouse buildings in the world. all greenhouse equipment in the Netherlands are automated devices, and the application of technology started earlier, and the greenhouse skeleton technology is more mature. In addition to PV systems fixed to the roof of the greenhouse, some companies offer movable PV systems that can be installed on the roof and have a higher power output per square metre of PV panel. Compared to fixed systems, tracking PV systems will generate around 20-30% more electricity.
Italy
A study at the University of Tuscany, Italy, presents an innovative PV greenhouse prototype with variable shading to optimise the energy production efficiency of PV panels and agricultural production. Unlike static PV greenhouse systems, a dynamic control system is used to rotate the PV panels to enable light management inside the greenhouse crop to adapt to the light requirements of the crop. In addition, by varying the position of the PV panel blades, dynamic shading can provide passive cooling for the crop in warm weather and the increased coverage can generate more electricity.
Spain
A Spanish trial designed an integrated translucent amorphous silicon photovoltaic (a-Si) glass greenhouse prototype covering the entire roof surface and the main sides of the greenhouse. The results showed that the presence of translucent PV glass slightly reduced plant quality and accelerated the apical growth mechanism of light-loving plants. From a statistical point of view, however, this effect was negligible and it was concluded that the integration of translucent amorphous silicon photovoltaic glass (a-Si) is feasible for horticultural production.
USA
Translucent organic photovoltaic arrays were used as roof shading for a greenhouse hydroponic tomato production system during a spring and summer production season in an arid region of the southwest USA. This study demonstrated the effectiveness of using translucent organic PV as seasonal shading for greenhouse production in high light areas.
Japan
In Maebashi, Gunma Prefecture, Japan, Farmdo has been running PV farm production since 2013 and currently has a total of nearly 10,000 sq ft of PV greenhouses on the farm. The farm’s photovoltaic greenhouses are arranged with single-sided photovoltaic panels on the top, which greatly improves the light transmission of the greenhouses while ensuring power generation rates and achieving efficient, ecological, energy-saving and sustainable agricultural development.
