Clean power sources, such as wind, solar, hydropower and biomass-to-energy, will provide all of California’s energy by 2045. In 2018, 91 biomass power plants in California produced about three percent (5.9 gigawatt-hours) of the state’s power from biomass conversion. Primary sources of biomass are byproducts and waste from agricultural crops, lumber milling and forest residues.
Climate change has increased the frequency and depth of drought, destroying tens of millions of trees in California forests. Left standing, these dead trees fuel and increase the risk of larger and more deadly forest fires. The dead trees can be harvested, processed and shipped to biomassconverting power plants, where they are stored in enormous chip piles. Over time, the chips slowly decompose, changing their physical and chemical properties and energy content. Carisse Geronimo, a master’s student at Humboldt State University, is working on a research project that will help biomass plants manage their chip piles to retain or improve the energy content of the wood chips to ensure this biomass source remains economically competitive.
Geronimo has always liked science and math. While growing up in Bakersfield, she spent a lot of time hiking in the San Gabriel and Sierra mountains with her dad. When it came time for college, she wanted a major that would allow her to combine science with resource conservation and sustainability. Geronimo started as a chemistry major at CSU Bakersfield and worked in a biochemistry lab during her sophomore and junior years. Under the direction of Dr. Karlo Lopez, she studied structure and function of lysyl oxidase, an enzyme that inhibits cancer cells during cancer’s early stages, but at later stages appears to promote metastasis. By her junior year, Geronimo had second thoughts about a chemistry degree and changed her major to biology.
After Geronimo graduated from CSU Bakersfield in May 2018, she found a program at the Schatz Energy Research Center at Humboldt State that combined the technical side of science with science advocacy and policy. She applied for, and received, the Donald and Andrea Tuttle Fellowship for Clean Energy Studies. This scholarship supports students interested in reducing the effect of climate change on humanity and ecosystems. She is working under Dr. Sintana Vergara and Dr. Kevin Fingerman, both faculty research associates at the Schatz Energy Research Center.
Geronimo started work on a biomass feedstock project in fall 2018. The project, co-funded by the CSU Agricultural Research Institute, seeks to understand what factors affect the decomposition and energy content of wood within these enormous wood chip piles. In her experiments, chips of various ages and tree species are subjected to different temperatures, moisture content and oxygen concentrations, and their decomposition rates and energy content are measured. Geronimo’s group monitors the physical and chemical properties of the wood chips that, during decomposition, emit greenhouse gases (carbon dioxide, nitric oxides and methane). She has found that the energy in biomass feedstock is related to its moisture content and age of the chip. As the wood decomposes, energy is released into the atmosphere, lowering the economic efficiency of the biomass plant. Geronimo’s experiments will provide insight on how to manage the decomposition process and retain heating value, energy content and reduce greenhouse gas emissions. Their early data indicate that separating chips by age, instead of mixing them, may be the easiest and most effective way to retain energy value.
Upon graduating, Geronimo would like to continue with similar environmental science-related work. Her long-term goal is to use her science knowledge and training to help inform public policy.