CSU unveils new agrivoltaic system at its Western Colorado Research Center in Mesa County
At Colorado State University’s Western Colorado Research Center, a new experimental system has recently been installed that will study how different types of solar arrays installed above its vineyard affect the grapes below and whether these systems can work together to produce both energy and a successful crop.
Colorado State University professor Horst Caspari explained that solar power requires a large amount of land and that land is often productive for agriculture. In order to preserve agricultural land while also producing power, some producers are going with “agrivoltaic” systems — a combination of agriculture and photovoltaics (solar panels).
What Caspari is interested in studying is how different types of panel arrangements and how they are managed affects the grapes.
“We will be comparing what the vines are doing in the open compared to where the solar panels are,” Caspari said. “And then within the solar array, we have two different types of panels.”
The system includes some panels that are semi-transparent, letting through around 60% of the light, and some that are fully opaque. The CSU array is divided into three sections, two with the semi-transparent panels and one opaque. The opaque section and one semi-transparent section will use what Caspari calls “dynamic tracking.” They won’t maximize their energy output, but will instead be managed to benefit the vines below.
“Instead of always following the sun and getting energy, during certain times of the year, I will say, ‘OK, now from sunrise to 11 o’clock you are not going to follow the sun, you’re going to go the opposite way. You’re going to turn the narrow side to the sun,’” Caspari said. “I want all the light coming into the grape. At 11 o’clock we’re going to hit 90 degrees anyway and the plants benefit from the shade, now we’re flipping back.’”
The third section will simply always follow the sun, maximizing energy output as a control, Caspari said. He estimates the dynamic tracking may reduce the panels’ output by around 11%.
The idea, if the right systems and management can be determined, is that the solar panels and agriculture could provide mutual benefits to both uses. Caspari said the covered crops tend to stay warmer at night and cooler during the day, which is appealing in the Grand Valley where frost events can damage crops and extreme heat can cause damage as well.
“We were almost six degrees warmer (at ground level under the solar panels) than we were there in the open,” Caspari said. “That is really huge. With wind machines we’re getting two, three, four degrees on a good night.”
Additionally, Caspari said the shade under the panels reduces evaporation, which can save water. When there is evaporation and transpiration, Caspari said the cooler, more humid air actually improves the solar panel’s performance above the crop. The panels also would protect crops from hail storms, like the one that damaged some vineyards earlier this year.
The system, which has only been installed for a few days and had its ribbon-cutting ceremony Thursday, is already showing promising signs. Caspari said they’ve been collecting data and will be monitoring a number of factors from temperature at different heights to even how the wine that is eventually made with the grapes taste.
Ultimately this testing could make a big impact for commercial producers. The opaque panels collect much more energy and so smaller systems can be used. That would make these systems more cost effective for producers if they can be managed to not harm the crop below.
The CSU system cost $450,000 and Caspari said he thinks it might pay for itself in 30 years. He said some systems for larger operations that use a lot of energy, like the one Tallbot Farms is installing, pay for themselves much quicker. They make less financial sense, currently, for smaller producers. However, if the panels reduced crop loss to frost and hail, that could also factor into how quickly they pay for themselves.
The CSU system was paid for with financial contributions from a number of organizations, including the Colorado Wine Industry Development Board, Colorado Department of Agriculture, the U.S. Department of Agriculture and the Western Colorado Community foundation, among others.
The system will be in place for years and also contribute to power the CSU research facility. Caspari said that even the first few days of getting to see the data have been exciting.
“This is good data,” Caspari said. “Holy smokes! This is very exciting data. We have to download the data manually. We’ve been actually going out every day, going, let’s look at this data again! It’s so exciting.”