Some ideas emerge overnight, while others are rooted more slowly, waiting for the right conditions to thrive.
Agrovoltaics is a system of solar panels and food crops that coexist on the same piece of land, which belongs to the latter category. Adolf Gotzberg Adolf Goetzberger, founder of the Fraunhofer Institute for Solar Systems, and Amin Zastro (Armin Zastrow) pioneered this concept in 1981. At the time, photovoltaic power was expensive and computers were seldom seen. So they studied the equations for dual-use systems on the programmable Pocket calculator and published a paper called Kartoffeln unterm kollektor (the potato under the panel)-Adolf Gotzberg later pointed out that this was a very easy to accept reason,
Because potatoes grow better in a little shade. 35 years later, the world seems ready for their ideas. Since 2010, the price of solar panels has plummeted by more than 50%-many farmers find it more lucrative to grow crops under huge solar arrays. For any farmer, this change is of economic significance.
But it has gradually built a game that could undermine global food security. Agrovoltaics is a way out of trouble. That is, if it can satisfy the world's voracious appetite for food and energy. There is one key question: Can farmers get the same food production under solar panels?
A growing number of studies have shown that they can. Too many shadows can hurt crops, too little damage to electricity.
The proper spacing between solar panels and the inclination of the array are key to getting the right combination of power and crop production. In 2010, Christian Dupraz and his colleagues at the National Institute of Agriculture in France established the first agricultural research farm near Montpellier. They planted two crops in sufficient sunlight, while the other was using a standard density photovoltaic array-a battery that generated the most electricity.
The third season crops grow under a half-density array, which allows more light to pass through the solar panels. At the end of the three growth season, crops planted under full-density panels have lost nearly 50% of their productivity. This is not particularly surprising.
It is worth noting that the plants under the half-density plate are as prolific and even more than the plants under full sunlight. For example, researcher Hélènemarrou explains that lettuce adapts to low light by increasing the leaf size. She also wrote in a 2013 paper that in a warmer world, water supply could be in short supply, and shaded plants under solar panels could reduce demand for water. ' We have shown in this experiment that the use of PVP (photovoltaic power systems) to cover irrigated vegetable crops can save 14% to 29% of evaporation water, depending on the level of shadow produced and crop cultivation.
' Too much shading can hurt crops, too little damage to electricity generation.
The proper spacing between solar panels and the inclination of the array are key to getting the right combination of power and crop production. On the basis of French research findings, German researchers at the Fraunhofer Institute-Adolf Gotzberg (Adolf goetzberger)-have begun to discuss the feasibility of large-scale farm operations. On one-third hectares of farmland near Lake Constance, Germany, they installed 720 double-sided solar panels-meaning they could capture light from above and below.
In France, however, their panel mounts are high from the ground, allowing the most daylight to reach crops and moving large farm equipment under the array. In September 2016, the researchers connected the solar test plant to the grid and planted winter wheat, celery, potatoes and clover under the array.
After the first year, the total output of food and electricity was 60% higher than the food and electricity harvested every two square meters. Compared to the clover that grows in the sun, the clover is the best, and the productivity drops by only about 5%. Yields on potatoes, wheat and celery have been reduced by about 19% compared to test plots without solar panels. Benedikt Klotz, a student assistant at the Fraunhofer Institute, explained: ' Overall power generation goes far beyond agricultural losses.
' These panels provide enough energy to power up to 62 homes a year; Klotz said the goal is to improve this goal in the future. The pilot research programme lasted for three years. ' Ultimately, we want to lead APV (Agrophotovoltaics) into the industry readiness stage of large-scale construction.
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Assuming that all lettuce grown in the United States is transformed into an agricultural photovoltaic system, it could increase the entire installed capacity of the country by one-fold. So how big is this? This is a recent problem solved by the Model Research Institute. For example, Joshua Pearce, an engineer at the Michigan Technical University, wondered what would happen if solar panels were installed on a grape farm in India. Considering the shade of the grapes, he and his colleagues created a techno-economic computer model, inserting numbers, and found that the economic value of Indian grape farms could be increased by more than 15 times times compared to traditional agriculture-the grape production did not decline.
If this dual use of land occurs in India, then energy generation may be enough to power 15 million people. Pearce and his colleagues also studied the cultivation of lettuce in the United States. Assuming that all lettuce production in the United States is converted to agricultural systems, photovoltaic power generation can be increased by 40 to 70,000 MW.
