Rapid reductions in the price of solar panels mean they are starting to appear in unexpected places, from balconies to motorway embankments. Now, researchers say they could play the role of hedgerows in farm fields, with double-facing solar panels generating power while acting as windbreaks for crops and livestock.
Farmers are already installing solar panels, often positioning tilted arrays over crops or allowing sheep to graze between panels. But such installations, known as agrovoltaics, can lead to excessive shading of plants or limit the land available for food production.
at Aarhus University in Denmark says one solution could be to place two-sided panels in vertical rows in fields. Placing panels vertically leaves maximum field space clear for farming, while allowing solar generation during the morning and evening if the panels face east and west. This orientation also avoids shading the plants when the sun is at its highest.
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鈥淲e know that solar PV is becoming cheaper and cheaper, so it makes sense to start thinking about new ways of using solar panels,鈥� says Victoria.
In Denmark, it is common for trees, wooden fences and even plastic sheets to act as windbreaks for crops. 鈥淲e thought, if we are going to do this, why not make these wind shelters produce electricity?鈥� says Victoria.
Together with colleagues, she conducted a year-long pilot study involving a 44.4-kilowatt system of double-faced solar panels in a field of winter wheat and grass clover, to assess the effect on crop yield. The panels had a 50-centimetre gap above the ground and rose to 3 metres in height.
The team found the vertical panels reduced average wind speeds over the crop field by around 50 per cent compared with a control field with no panels. The panels also helped to maintain humidity in the field, compared with the control field, and there was no reduction on crop yield overall, says Victoria.
The panels generated much less electricity than a standard tilted array, but it was produced in mornings and evenings. 鈥淚t matches better when there is high electricity demand in the system,鈥� says Victoria.
Next2Sun, a German tech firm, has already developed a number of commercial vertical agrovoltaic projects across Germany, and even produces 鈥渟olar fencing鈥� for farmers. But Victoria鈥檚 research, which hasn鈥檛 yet been peer-reviewed, is one of the first to specifically assess the impact of this set-up on crop yield.
at the University of Arizona says vertical panels could work well at higher latitudes, when the sun is lower during winter seasons. He stresses that the research is still at an early stage, with more work needed to assess the performance of the system during extreme weather and with different crop types.
Crops taller than 50 centimetres could be shaded by the panels, he says. But for high-value crops, such as grapevines or berries, the system could work well. 鈥淭here鈥檚 going to be a way forward that brings renewable energy and agriculture together,鈥� he says.
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