Energy Farming: Sweet Sorghum and Algae
Think of Agricultural Experiment Stations as outdoor laboratories. Test fields bloom with experiments for citrus, produce, and commercially promising alternative crops such as guayule. But University of Arizona’s Red Rock Agricultural Experiment Center (RRAC) is also growing energy.
Both sorghum and algae are highly regarded sources for biofuel. That means they not only offer a potential stream of revenue, but an avenue to domestic energy! Though still in development as an energy source, experts expect breakthroughs over the next few years that will make production of these crops not only economically viable but lucrative. Our state universities are working hard to develop these advancements in the lab. Learn more about biofuel development.
Some farmers are already seeing the potential of these crops. In fact, both are on a list of emerging crops circulated by the Arizona Farm Bureau. So don’t be surprised to pass algae pools or sorghum fields on the way to your next Arizona adventure.
Growing about 3-4 meters tall, sweet sorghum looks like a cross between corn and bamboo. Like sugarcane, it has a high sugar content. But its carbohydrate chains will not be ingested. Instead, they will be processed into ethanol, the biofuel already produced from corn. But whereas corn yields around 300 gallons of ethanol per acre, sweet sorghum produces nearly double that—between 500–600 gallons per acre.
Sweet sorghum is a popular desert cultivation experiment not only because of its biofuel potential, but because it is a drought tolerant, salt-tolerant, and generally tough crop. For the past six years, 40 acres have been grown experimentally at the RRAC with help from a large grant from the U.S. Department of Energy. Researchers and grad students are developing ways to efficiently produce biofuel that may eventually power homes, automobiles, factories, and airplanes.
Raised in water and fed by sunlight, algae has enormous potential as a cheap, renewable source for energy. An algae crop takes only one to two days to mature, so harvests are frequent. Algal biomass is 60% lipid that can be converted to biofuel. An acre of algae has the potential to produce an estimated 10,000 gallons of biofuel per acre, up to one million gallons per year. The remaining biomass is a high value fertilizer, animal feed, or fuel.
Algae farms prosper in Arizona’s warm climate and abundant sunlight. But algae's real value may be its potential to treat water. Algae eat farm waste nutrients such as nitrate, ammonia, and phosphate from contaminated water such as agriculture irrigation runoff. They also eat carbon dioxide from flue gas emissions. However, one of their favorite environments is dairy effluent. Algae farmers who use dairy wastewater in algae pools rarely have to add commercial fertilizer. Overall, algae’s growing conditions and potential as a commercial crop, both for its energy creation and its water purification capabilities, are very exciting.
About the Red Rock Agricultural Experiment Center
The idea for an “energy farm” was conceived in the 1970s during the oil crisis to help establish a domestic, renewable source of energy. Today a 300 acre plot located 35 miles north of the U of A main campus cultivates algae and sweet sorghum for biofuel development. The location’s abundant sunlight makes it the perfect breeding ground for algae and for the solar panels used to power to parts of the energy farm.
The remaining 4,600 acres of state land that makes up the RRAC are devoted to large-scale field research projects in plant breeding, weed control, plant pathology, insect management, fertility & nitrogen management, soil conservation, and alternative crops.