Can solar panels and pastoral farming work together?

An improved understanding of the effect of solar arrays on pasture production could inform future decision-making about what kinds of co-located systems (Agrivoltaics) might be feasible, or even lead to alterations in solar array construction to better facilitate farming practices beneath and between panels.

Massey completed a pilot study on pasture growth under a solar array in South Taranaki in 2023. This research showed that pasture growth was reduced by 84 per cent beneath solar panels, but increased by 38 per cent between panels. Researchers are now trying to understand the causes behind the reduced growth.

Solar panels can significantly reduce the amount of sunlight reaching pasture plants beneath panels, but it was clear from the pilot research that they may also provide beneficial effects for pasture growing between panels in some regions or seasons.

The pilot study was conducted during the summer months, so it is possible that pasture plants shaded for parts of the day during warmer, drier seasons are better able to conserve moisture, while plants exposed to hot, sunny conditions for extended periods are forced to expend moisture. Plants regulate leaf temperatures in this way. Pasture plants rarely use all the sunlight they are supplied, so intermittent shading by solar panels in the paddock throughout the day is unlikely to have major impacts on pasture growth.

In the new research, the scientists intend to measure critical characterises of the environment relevant to pasture growth to examine the possible explanations and reasons for the original results.

Massey researchers have constructed a mock solar array at the Pasture and Crop Research Unit, which is part of Massey Farms. The mock solar array has been produced to the same specifications as a commercial solar array, but instead of solar panels and steel framing, the team has opted for more cost-effective wood and iron structures.

The research will examine pasture production, botanical composition and nutritive value, as well as soil fertility and carbon stocks, light availability, wind speed and direction, rainfall, humidity, soil moisture, soil and air temperature. By measuring all of the important drivers of pasture growth, the researchers hope to gain a full understanding of just how solar arrays might be affecting pasture production.

The research team consists of Sam Wilson, Dr Andrew Cartmill, Associate Professor Rene Corner-Thomas, Professor Danny Donaghy and Professor Paul Kenyon.

Trevor Ellett Lecturer in Grassland Science Sam Wilson from the School of Agriculture and Environment says the research forms part of an ongoing programme to consider combining different businesses on farm to get the most out of our land-based industries.

“A lot of this solar research has become current over the last few years as farmers seek to enhance both production and sustainability. We are working with farmers seeking to increase the profitability of their businesses and at the same time, generate renewable energy. This work supports those goals.”