Sheep grazing underneath solar panels at Oregon State University.

Mixing sheep grazing with solar farms yields major land productivity increase

Image credit: Oregon State University

Combining solar farms and sheep grazing pasture in the same area could massively increase land productivity, a study has found.

Oregon State University scientists compared lamb growth and pasture production in pastures with solar panels and traditional open pastures.

They found less overall but higher-quality forage in the solar pastures and that lambs raised in each pasture type gained similar amounts of weight. The solar panels provide additional value in terms of energy production, which increases the overall productivity of the land.

Solar panels also benefit the welfare of the lambs by providing shade, which allows the animals to preserve energy. Also lamb grazing alleviates the need to manage plant growth under the solar panels through herbicides or regular mowing, which require extra labour and costs.

“The results from the study support the benefits of agrivoltaics (co-developing the same area of land for both solar photovoltaic power as well as for agriculture) as a sustainable agricultural system,” said lead author Alyssa Andrew.

The study, which was carried out in 2019 and 2020, found that the daily water consumption of the lambs in the two pasture types in spring 2019 were similar during early spring, but lambs in open pastures consumed more water than those grazed under solar panels in the late spring period. However, there was no difference observed in water intake of the lambs in spring 2020.

Over the course of the study, solar pastures produced 38 per cent less forage than open pastures.

Solar photovoltaic installation in the US has increased by an average of 48 per cent per year over the past decade, and current capacity is expected to double again over the next five years, the researchers said.

Past research has found that grasslands and croplands in temperate regions are the best places to install solar panels for maximum energy production. However, energy production in photovoltaic systems requires large areas of land, potentially causing a competition between agricultural uses.

Agrivoltaics looks to diffuse that competition by measuring the economic value of energy production and agricultural use of the same land. Past research has focused on crops and solar panels and found that some crops, particularly types that like shade, can be more productive in combination with solar panels.

Another recent study found that shade provided by solar panels increased the abundance of flowers under the panels and delayed the timing of their bloom.

“The overall return is about the same, and that doesn’t take into account the energy the solar panels are producing,” said co-author Serkan Ates. “And if we designed the system to maximise production we would likely get even better numbers.”

In March, another study found that floating solar panels on top of reservoirs helped to protect them from negative climate change effects.

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