Originally published on PV Solar Report.
By Rosana Francescato
A new study looks at the benefits of double-purposing land for agave cultivation and solar panels. The advantages of this ingenious solution go beyond the usual benefits provided by agrivoltaics.
As solar spreads around the country, siting can become an issue. Sometimes that’s resolved by using already compromised land — we’ve seen solar over parking lots or on landfills, even on some Superfund sites.
Many large solar plants are built in desert areas in the Southwest, which have the advantages of ample space — often not suitable for farming — and plenty of sun. Those areas are not problem-free, though.
Researchers at the TomKat Center for Sustainable Energy at Stanford were thinking about this, and they noticed a connection among a few problems:
A lot of water is needed to clean solar panels in dusty, arid areas.
Desert areas aren’t good for growing most crops.
A lot of farmland is being used now to grow corn and other grains for ethanol, but grains aren’t the most efficient source for producing the fuel.
What, you ask, can those three things possibly have in common? These are the answers from Sujith Ravi and his group of Stanford researchers:
A good use of water is to double-purpose it for panel washing and farming.
The agave plant thrives in the desert.
Agave is a good source of ethanol, because most of the plant can be used to produce the fuel.
Do you see where they’re going with this? That’s right, the researchers’ answer to all these problems is to co-locate solar and agave production.
A study published in the journal Environmental Science & Technology provides more details on this idea, but it’s a simple one: Water is needed at PV solar farms to remove dust and dirt from the panels and to dampen the ground to prevent the buildup and spread of dust. The water from that cleaning is just about the right amount for agave plants, which can be placed between and under the panels to capture the runoff. The plants provide yet another benefit: because their roots help anchor the soil and their leaves help keep wind from kicking up dust, they can reduce the dust in the area.
Computer simulations conducted by the team suggest that this plan would reduce the amount of water needed at solar farms, while bringing agriculture to arid regions. “It could be a win-win situation,” Ravi said in a news release. “Water is already limited in many areas and could be a major constraint in the future. This approach could allow us to produce energy and agriculture with the same water.”
The concept of agrivoltaics, which combines solar PV and agriculture to maximize land use, is not new. Some studies have even found that crops that are partly shaded by solar panels are sometimes even more productive than those that aren’t. This new research builds on the concept by allowing more use of arid land combined with a better way to produce ethanol.
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