Distancing rows of solar panels apart can help maintain the module temperature, which usually increases when solar modules are exposed to direct sun for a long time leading to a decrease in module efficiency, a new study by the National Renewable Energy Laboratory (NREL) has revealed.

Irradiance is the primary driver of module temperature, but it also results in an average drop of around 0.3%-0.5% in a module’s maximum power output.

Gutters between the panel rows create paths for the wind to flow so the excess heat in the modules due to prolonged exposure to the sun can be reduced, ultimately improving module performance with convective cooling efficiency.

The amount of ground-reflected irradiance on a solar module increases when the panels are distanced. The gutters also help decrease the incidence of modules casting shade on each other.

The study – ‘Technoeconomic Analysis of Changing PV Array Connective Cooling Through Changing Array Spacing’ is published in the IEEE Journal of Photovoltaics.

The analysis, which relied on NREL’s System Advisor Model, demonstrated that a greater separation between rows would improve the performance of a PV system by allowing airflow to cool down the solar modules.

NREL researcher and lead author of the study, Matthew Prilliman, observed, “When you look at the layout of the system, like how the modules are spaced apart, what angle they’re at, how high they’re off the ground—that all affects airflow.”

He said few previously used computer models considered the changes in heat transfer caused by differences in how an array is configured.

However, the researchers found that a greater separation of rows carries additional costs. Notably, more land is needed as the arrays are spaced out more. In addition, wiring costs increase as the arrays are more spread out. Crucially, the researchers determined the benefits outweigh the costs in many cases.

The research could be particularly relevant for the growing field of agrivoltaics, in which crops are planted adjacent to or below solar panels. The changing land usage for different layouts would affect the placement of crops, which could, in turn, also affect wind flow.

Lead author of another NREL research focussed on agrivoltaics, Jordan Macknick, said, “Increasing spacing could enable more varieties of crops and more types of agricultural equipment to be utilized in agrivoltaic systems. That could potentially make these spaced-out solar systems more cost-effective and compatible with larger-scale agriculture.”

In India, agrivoltaics have slowly been gaining ground as they help solve the rising need for land to ensure both food and energy security. Several entrepreneurs are giving agrivoltaics a shot.