Page 51 - Energize March 2022

TECHNICAL

Agrivoltaic systems have been the subject of numerous
studies covering technology, system configurations and designs,
due to their potential in the food–energy nexus. Demonstrative
2
projects with new conceptual designs, based on PV modules
for covering open fields, have shown promising results through
optimising light availability while reducing the need for irrigation
and protecting from extreme weather phenomena.

Advantages for PV
PV panels in an agrivoltaics application perform better than PV
panels in an open ground environment. Increased height and
increased air circulation leads to lower panel temperature, and
crop dynamics underneath the solar panel also lead to a reduced
temperature which increases the output (Figure 2).
Although standard solar panels and mounting systems can be
used for AGV, it has been found that specially designed panels
give better results and allow better control of light and shade over
the seasons.
Figure 2: Vegetation under panels result in lower panel temperature
Rainwater harvesting (Walterschindler)
Incorporating a rainwater harvesting feature into an AGV
system offers further benefits for crop production and water the panels. From an agricultural point of view this also increases
conservation. Such a system could comprise guttering at the the connectivity between plant beds, which is apparently an
lower edges of the solar panels which channel water into a important criterion. The other factor is the increased spacing
large water tank feeding a drip irrigation system to the roots between rows.
of the plants. Raised on a plinth, this system could be entirely
gravity fed, thus avoiding the need for additional mechanics and Standard panels in a continuous row with no separation. (Figure 3)
electronics which could fail. Rows are orientated east-west. The panel row creates a continuous
Rainwater harvesting would maximise the amount of shadow that moves in a north-south direction following the
rainwater reaching the crop roots, rather than evaporating from elevation of the sun. Shadow movement is influenced by the height
above-ground plant biomass and the soil surface or running off of the panels. Crop placement depends on the suns/shade ratio
into drainage ditches. Controlled irrigation, rather than relying on required and can vary from underneath the panel to the rows
rainfall, would enable storage of water from rainfall events to be between the panels.
used for irrigation at a later date during periods of low rainfall. One source suggests a north-south orientation which would
give greater movement to the panel shadow and allow more light
System design and technology under the panel. But this would require a flat panel tilt or each
Agrivoltaics has spawned a wide variety of new products and panel tilted individually. This may work on hillside environments.
system configurations. Some of the most common are described
below. Fundamental to all configurations is raising the height of Standard panel rows with spacing between panels. (Figure 4)
the panel support structure to allow access to workers and farm Each panel creates a single shade patch, the movement of which
machinery. This also improves air flow and ventilation under follows both the elevation and azimuth of the sun. This allows a

Figure 3: Jacks solar garden in Boulder Colorado (NamastéSolar, NREL)

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