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Viable Biomass for Hawaii
by Gretchen Miller (Biofuels Digest) ... Meghan Pawlowksi, a graduate student at the University of Hawaii Manoa’s College of Tropical Agriculture, crawled around her field site on the last sugarcane plantation in Hawaii, Maui’s Hawaiian Commercial & Sugar Company, or HC&S, collecting field data for two years. Her study was unique because it was the first in-depth study of tropical grasses as a biofuel option for Hawaii; she was hoping to determine the best biofuel crop to grow in Hawaii. Last month, she published the results of her long days in the field with her advisor, Dr. Susan Crow, UH Assistant Professor of Soil Ecology, in a peer reviewed scientific journal called PLOS ONE.
In January 2017, at the same time their article was published, HC&S closed, marking the end of 150 years of plantation agriculture in Hawaii. The citizens of Hawaii, landowners, policymakers, and researchers are sitting with the question of what the best uses for thousands of acres of old plantation fields are for future generations.
The team investigated two tropical grasses: sugarcane and Napier grass, to see which was best to grow on fallow sugarcane lands for biomass energy production. Results of two years of field data show that Napier grass grows very quickly with relatively low levels of water to produce biomass fuel material, and is also extremely effective at holding carbon in the soil to reduce global warming. Dr. Crow explained, “Carbon is being held in the soil itself. The plant roots are the conduits to transfer it back to the soil. Then it’s stabilized … and will continue to hold the carbon in the soil for a very long time with zero-tillage, or zero-plowing, practices. When you work to accumulate carbon in the soil, you’re rebuilding the quality of the soil. Over time we rebuild soil health; as the soil heals we can also reduce the amount of water and fertilizer needed for Napier grass cultivation,” Dr. Crow said.
Biomass could be helpful “… on cloudy, windless days, where supply is low and demand is high. We could use pelletized biomass on days of high need,” Dr. Crow said. “The grasses could also be feedstock for a digester to produce methane, which we can burn for fuel. Waste products from this methane production can then be returned to the soil by composting.”
Joelle Simonpietri, Energy Program Manager at UH’s Applied Research Lab, addressed another of the controversies surrounding biofuel production directly, “Quite often there’s a food versus fuel question or conflict. A better question is: How can we most effectively use our landscape to produce food and fuel for a sustainable Hawaii? There’s plenty of land for everything if we start planning now with the buy-in of prominent land-owners and farmers.” Reframing the common food versus fuel debate to a food and fuel conversation could help Hawaii move towards an integrated food and fuel system for greater food and fuel security. READ MORE Abstract