One of the main arguments against extensive solar power installations is that solar farms require a lot of land—land that the agriculture industry craves as well.
But what if it doesn’t have to be an either/or choice? What if solar farms could co-exist with agricultural farms?
They can. Recent studies and pilot projects in Europe and the United States have shown that dual-use solar farm/farming is possible.
The so-called agrophotovoltaic (agroPV) projects can benefit crops because the solar modules serve a dual purpose—not only do they generate electricity, but they also protect crops from hail and keep shade-loving crops such as leafy vegetables out of direct sunlight while still providing some light via semitransparent solar modules.
For farmers, having a solar installation can reduce electricity costs, diversify their revenue stream, and potentially extend growing seasons, the U.S. Department of Energy says in its Farmer’s Guide to Going Solar.
For those concerned that solar modules could overheat and dry up crops, the guide says that solar modules actually cool crops and vegetation due to shading, and keep them warmer at night. Studies have also shown that there was no impact on crop growth rates. In addition, grazing sheep can be used to control vegetation, as they do not climb or harm the installations.
Can AgroPV Solve Solar Energy’s Land Issue?
One of the thorny issues in the drive toward increased solar power generation is the massive amount of land that solar modules sucks up, potentially displacing agricultural land with solar PV modules used only for energy production.
Based on DOE estimates, solar energy capacity in the United States could reach 329 gigawatts (GW) by 2030—but this would require approximately 1.8 million acres of land, the National Renewable Energy Laboratory (NREL) says. Although those nearly 2 million acres—approximately the size of Delaware— would be less than 0.1 percent of total land area in the United States, concerns have grown over the use of agricultural land for solar installations to the point that counties in Connecticut, North Carolina, and Washington have restricted development of solar PV over farmland to protect cropland.
But according to NREL, low-impact solar development over farmland spares farmers and energy developers from this ‘either-or’ choice and brings mutual benefits to both.
AgroPV may not be feasible for huge single-crop farms, but it can boost the yield from certain plants. Preliminary results suggest that cherry tomato yields at an Arizona site of NREL solar farm/farm project have doubled and need less water when grown in the shade of solar panels.
The dual-use solar farm/farm sites could be a solution to the land issue for states and counties in the U.S. with limited farmland, as well as for countries in Europe and northeast Asia.
Still, the controversy persists about the trade-off of covering agricultural land with solar modules, especially for larger-scale agroPV projects.
For example, the Nichomus Run Solar Farm in New Jersey, which will be the state’s largest, will generate a peak output of around 150 MW of clean power, equivalent to the demand from 24,000 NJ homes annually. Project developer Dakota Power Partners plans rows of solar panels that track east to west and grazing sheep to manage vegetation, which would otherwise require mechanical mowing. The project is expected to become operational in 2021 or 2022.
“The farming community is greatly in support of the dual-use. And they’re not opposed to the grid-scale either; but the dual-use is like a grand slam home run, because you continue to farm and you also get revenue from the rental of the property for solar,” New Jersey State Senator Bob Smith told NJ.com.
The New Jersey Conservation Foundation begs to differ and calls for growing crops, not solar panels, on NJ’s best farmland, commenting on a proposed law to encourage large utility-scale solar projects without provisions to keep it off the best farmland and open space.
“Reducing the state’s reliance on fossil fuels is critical to combating climate change. But solar energy projects must be built in the right places. And high-quality farmland and forests are most definitely not the right places!” the foundation said last week.
AgroPV Helps Crop Yields
Still, various studies have shown that low-impact solar modules can benefit crop yields. The Fraunhofer Institute for Solar Energy Systems ISE in Germany found last year that the performance of an agroPV system at a project in the very hot summer of 2018 was beneficial to both crops and power generation.
“Based on the 2018 potato yield, the land use efficiency rose to 186 percent per hectare with the agrophotovoltaic system,” Stephan Schindele of Fraunhofer ISE said. Another Fraunhofer ISE pilot study carried out for the Indian state of Maharashtra showed that shading effects and less evaporation result in up to 40 percent higher yields for tomatoes and cotton crops.
The AgroPV Market Is Growing
India is one of the busiest markets for agroPV because 60 percent of the land is used for agriculture, and the sun is abundant, BNEF said in a recent analysis.
“AgroPV is one step closer to smarter sustainable agriculture, which is what we have been promoting across India and the world,” Ajit Jain, joint managing director at agricultural technology company Jain Irrigation, told BNEF.
The five most advanced agroPV markets in the world are China, Japan, France, South Korea, and Massachusetts in the United States, according to BNEF.
AgroPV needs more research into which crops could be paired with solar modules, but research from companies and laboratories in Europe and the U.S. have shown that low-impact solar installations can co-exist with farmland and even boost crop yields, without posing the choice ‘land vs clean energy generation’.
“It doesn’t have to be an either-or choice. For all our agriculturally productive land, let’s help PV developers and farmers plan out these solar projects so that farmers can get under the arrays and continue to work the land for the next 20 or 30 years,” Gerry Palano, energy program coordinator, Massachusetts Department of Agriculture, says on NREL’s website.