PROSSER, Wash. – The Washington State University Center for Precision and Automated Agricultural Systems will team up with University of Hawai’i at Mānoa and others to modify existing sugarcane harvesting techniques and systems to handle tropical grass crops for biofuel.
The work is part of UH-Mānoa’s four-year, $6 million project to help Hawaii increase its energy security by growing sustainable biofuel feedstocks. The project is funded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture. WSU’s Center for Precision and Automated Agricultural Systems (CPASS) will lead the mechanical harvest systems component, funded at $709,000.
WSU expands biofuel research role
“Participating in this project will further reinforce WSU’s strong competence in biofuel research,” said Qin Zhang, WSU CPASS director. “By filling the gap in engineering solutions for feedstock production, we’re helping to make WSU one of the leading institutes in biofuel research in the world.”
According to UH-Mānoa, the project will examine the use of fast-growing tropical grasses such as bana grass, sweet sorghum, energy cane (a relative of sugarcane) and Napier grass-pearl millet crosses for biofuel production. Researchers also will assess the sustainability of renewable-energy production in Hawaii, which uses imported fossil fuels to meet more than 90 percent of its energy requirements.
Highest energy cost in nation
Despite almost-nonexistent heating needs, Hawaii has the nation’s highest energy costs. The U.S. Energy Information Administration, the Department of Energy’s statistical and analytical agency, notes that per capita energy consumption in Hawaii is among the lowest in the nation. But the transportation sector leads energy demand in Hawaii, accounting for more than half of the state’s total energy consumption. This is due in large part to heavy jet-fuel use by military installations and commercial airlines.
WSU CPASS is working with researchers from Oregon State University; ZeaChem Inc. of Lakewood, Colo., a developer of biorefineries to convert renewable feedstocks into sustainable fuels and chemicals; Hawaiian Commercial and Sugar Co. on the island of Maui, Hawaii’s largest provider of raw sugar; and Hawai’i BioEnergy LLC of Honolulu, a leading renewable-energy supplier to the Hawaiian Electric Co.
Improving harvesting systems
Zhang, Lee Jakeway, HC&S director of energy development, and Manoj Karkee, WSU assistant professor of biological systems engineering, presented a harvesting systems plan at a task leaders’ meeting May 14-15 at UH-Mānoa. Their goal for improving tropical crop harvesting systems is to optimize cutting and collection with low operating costs and losses, they said.
Zhang and his WSU team will evaluate sugarcane harvesters in the first two years of the project, looking at the efficiencies of different operating speeds compared to the growth stages of tropical grass crops, as well as the effect of varying terrain on the harvesters. Performance measures will include material flow efficiency, harvest speed, exclusion of dirt and mud, crop loss, machine productivity and energy consumption, and how much land is required for effectively turning the machine around at the end of a field.
During the third and fourth years, Zhang and the WSU researchers will improve the harvesters to accommodate differences between sugarcane and tropical grass crops, modifying the cutting mechanism as needed. They will also study whether rock detection sensors will be necessary on the harvesters to minimize damage to cutters.
Cutting mechanism development and lab testing will take place at WSU CPASS in Prosser, with final field tests planned in HC&S fields. Zhang and his team will investigate how the harvesters operate when used for one or multiple passes and seasonally versus year-round. They will also determine how well the modified harvesters work for cutting, chopping, shredding, conveying and baling tropical grass crops.
“The long-term goal is to search for sustainable and cost-effective processes and to develop effective and efficient equipment for harvesting and collecting biofuel feedstock from the field,” Zhang said.
WSU CPASS, established in 1999 as the WSU Center for Precision Agricultural Systems, promotes creative research and extension activities for more effective growing, harvesting and processing of specialty crops through mechanization and automation. For more information, visit the WSU CPASS website.