The boom in solar energy around the world has led to huge numbers of panels being installed on prime agricultural land, taking quadrillions of calories out of the global food supply.
More than 5000 square kilometres of the world鈥檚 surface was covered by solar photovoltaic (PV) panels in 2018 鈥� 1655 times more than in 2003. Much of that has happened on cropland that could produce enough food to feed millions of people, according to a study by at Zhejiang University, China, and his colleagues.
The team used satellite imagery to detect where cropland has been covered with solar panels around the world, before calculating the food production impact. 鈥淥ur research reveals an exponential increase of PV installations on cropland,鈥� says Xiao.
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Around 27 per cent of all solar installations worldwide took over cropland in 2018, the latest year of data, totalling about 1371 square kilometres of land, the team estimates. This was responsible for food production losses in the region of 4 petacalories in 2018, an amount that could feed 4.3 million people for a year. In scientific terms, the 鈥淐alorie鈥� used in common parlance, for example on some food labels, is actually 1000 calories, while a petacalorie is a million billion calories.
On current trends, the lost food production could climb to 62 petacalories a year by 2050. 鈥淚f we continue to encroach on cropland of similar cost (food loss per solar energy gain) at the current rate, it will lead to a 16-fold increase in annual food production losses compared to 2018, driven by the rapid growth in demand for PV solar energy,鈥� says Xiao.
China, eastern North America and western Europe face some of the most intense conflicts between using cropland for food or energy production, the research found.
However, Xiao says the study, which hasn鈥檛 yet been peer reviewed, may have overestimated food production losses because it assumed there would be no crops or pasture below solar panels. Grazing sheep alongside solar panels, for example, has been shown to be an effective method of raising livestock.
The losses will continue to climb as solar energy encroaches on cropland, unless policy-makers take action, says Xiao. 鈥淚 think the biggest concern is sound planning, choosing the right place for the right land use,鈥� he says. 鈥淎 blanket ban on PV construction on all cropland is clearly unreasonable. What we are looking for is a win-win situation between energy demands and food security.鈥�
at Princeton University notes that the paper doesn鈥檛 account for future productivity improvements in agriculture, which would allow more calories to be produced per acre of cropland. 鈥淚 would expect that it [productivity improvements] would more than compensate for the loss that comes from the solar,鈥� he says.
Efficiency improvements in solar technology could also reduce the amount of land needed for energy generation, says at Cornell University in New York. 鈥淚鈥檓 hoping we will still see more efficient panels being adopted and better designed solar farms that use land more efficiently,鈥� he says.
Some see demand for solar energy as an impetus for change in the farming industry. Arable farmer , of the UK鈥檚 Nature Friendly Farming Network, says farmland could be used more efficiently to make room for solar. 鈥淭he reality is that 62 per cent of the grain that we produce in the UK feeds livestock,鈥� he says. 鈥淲e need to be realistic around the amount of land we use globally to feed livestock.鈥�
In the future, people might see farmers as producers of energy as well as food, he says. 鈥淲e need to rethink the role of the farmer and the outputs they produce.鈥�
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