The Department of Engineering Technology’s Assistant Professor Gowtham Mohan has secured a three-year, $570,000 award from the BARD (Binational Agricultural Research and Development fund) to develop a new spectrally-selective semi-transparent plastic bifacial solar panel design which may be used in co-located agrivoltaics operations in the US and abroad.
In hot and arid climates, crops are exposed to large amounts of solar radiation; just like in humans, this may lead to sunburn, excess water loss and consumption and lower overall productivity. The co-location of photovoltaic installations and agricultural fields, commonly known as agrivoltaics, presents a viable solution to protect crops from sunburn and reduce transpiration while simultaneously serving as a source of clean electricity.
“We propose an agrivoltaic system built with an array of bifacial monocrystalline silicon solar cells (distributed evenly) covering half of the solar collector area that utilizes 50% for electricity production and transmits the rest to the agricultural field to achieve optimum capacity through a spectral-splitting reflector,” said Mohan. “The spectral reflector transmits photosynthetically active blue and red wavelengths and reflects the rest to the bifacial panel. This leads to higher electricity yield and, most importantly, improves crop health and yield and photosynthetic activity. This system will be encapsulated with thermoplastics for long lifetime, lower cost, and weight.”
Agrivoltaic practices have experienced “notable progress across several countries” over the last several decades, but while co-location of photovoltaics has proved effective for certain crops, it is not effective for all varieties due to over-shading by the solar installation. With this new design, the system will be tested on lettuce, tomatoes and strawberries, and will be evaluated on combined electrical conversion efficiencies, agricultural yields and reduced water usage.
“This is a multinational sustainable energy and environmental project spanning multiple different specialties,” Mohan added. The project is a collaboration between the United States and Israel, and will involve extensive testing in desert environments (wherein crops receive greater, more intense sunlight and require more shade) across both countries.
“I’ve had this idea for the last five years,” said Mohan. “The conventional, commercially-available panels installed in agricultural fields have cells on only one side, and they shade the plants completely. This reduces the crop yield; some crops grow well in 100% shade, but not all. We started exploring the idea of solar panels that allow some light to pass through via spacing between the cells. This started at the University of New Mexico, where I received a Department of Energy grant to build and test a small prototype, and we got very positive growth results — crop yields as high as two to three times non-covered crops and fully-obstructive panels.
“This project is a continuation of that research,” he added. “This idea has been explored in Australia, Europe and the United States, and this new panel we are developing can be implemented in any country and any location. You can install it in Israel or here in Texas, here in Fort Bend County or Harris County, on small strawberry and tomato and chili pepper farms, and also help the farmers to find additional revenue or the electricity they need for irrigation pumping and such. This system can contribute to a more sustainable food-water-energy nexus.”