The onset of climate change threatens every aspect of our lives. However, rising temperatures and increased severity of weather events simultaneously threaten our food, energy, and clean water. The sustainability movement seeks to rectify this by slowing climate change, conserving resources, and promoting an equitable global society.
Agrivoltaics is one of many innovations that might help solve some of these problems. In a critical 2019 study, scientists from the DOE’s National Renewable Energy Laboratory (NREL), the University of Maryland, and the University of Arizona examined how agrivoltaics affects the balance of energy, food, and water. This roundup summarizes their findings, explaining how combining solar power and agriculture can help us reach a sustainable future.
The Problems with Traditional Solar Power
As pointed out in the study, traditional solar panel arrays use gravel to cover barren land. This gravel absorbs heat from the sun, trapping it then releasing it slowly. This phenomenon creates a heat island, similar to how the asphalt in urban areas keeps temperatures higher than in the suburbs or rural areas.
Unfortunately, photovoltaic (PV) cells (the parts of a solar panel that converts sunlight into electricity) lose efficiency at higher temperatures. This effect means that the already land-inefficient solar array needs even more space to generate the same amount of energy, especially in hotter climates. One of the main ideas behind agrivoltaics is that replacing gravel with certain crops can alter the microclimate near the solar panels, boosting efficiency.
The Study
The NREL study used chiltepin peppers, jalapenos, and cherry tomatoes planted either in an open field (as a control) or under elevated solar panels. They measured light, temperature, humidity, and other metrics above and below the ground surface in both fields for three months. Besides the presence of solar panels over the test crops, the treatment and irrigation were identical.
The Benefits of Agrivoltaics
The results varied from one plant type to the other, but all three benefited from the presence of solar panels. Moreover, the test showed positive impacts on energy efficiency and water conservation. Although this was a single study, others have shown similar results for single metrics or specific crops. Taken together, these results are likely scalable, and agrivoltaics may be a helpful tool to help us solve our water, food, and energy problems.
Food production
The yield was over double the control crops for the cherry tomatoes and chiltepin peppers, with the peppers approaching three times the productivity. Similarly, the jalapenos and cherry tomatoes required much less water than their counterparts exposed to the sky. Solar panels boosted yield and reduced water consumption across the board.
Energy Production
The solar panels averaged 9 degrees C cooler than gravel-based panels and recorded higher levels of efficiency, especially during the day.
Water Saving
The solar panels helped the microclimate retain moisture, and the covered soil water content remained higher than the uncovered soil by 5% after 24 hours without irrigation. More notably, it was 15% higher after 48 hours without irrigation.
Key Takeaways
- Water – Agrivoltaics boosts water efficiency. What can you do to help? Consider using greywater to irrigate your flower garden. All it takes is a bucket to collect extra water in the shower. You can even use water from your washing machine as long as there are no chemical detergents.
- Energy – Efficiency is key. Whether by adjusting habits or buying newer appliances, do what you can to lower your power draw, especially during peak times when production is less efficient.
- Food – Locally grown, organic foods are more nutritionally dense than industrially farmed alternatives. They also have lower emissions and boost the local economy. Do your best to eat foods that are grown efficiently and sustainably.
