Asiful Alam

Decarbonizing Oregon’s heavy-duty trucking sector, which accounts for 24% of the state’s transportation emissions, is essential for meeting carbon reduction targets. Drop-in fuels such as renewable diesel, biodiesel, and synthetic fuels provide an immediate and effective solution, reducing emissions by up to 80% while utilizing the existing diesel infrastructure. In 2023, Oregon’s heavy-duty trucks consumed 450 million gallons of diesel, with drop-in fuels making up 15% of the fuel mix. Renewable diesel, which is growing at a rate of 30% annually, accounted for 10% of this volume, thanks to incentives from Oregon’s Clean Fuels Program. By 2030, drop-in fuels could capture 40% of the market, reducing CO₂ emissions by 3.5 million metric tons annually, assuming continued policy support and advancements in feedstock sourcing. Meeting the projected demand of 200 million gallons annually and securing sustainable feedstock remain critical challenges. Advances in synthetic fuels, like Power-to-Liquids (PtL) from renewable energy, may further contribute to decarbonization, with costs expected to decrease by 20% over the next decade. Oregon aims for a 50% reduction in emissions from heavy-duty trucks by 2050, using a mix of drop-in fuels and emerging technologies. While hydrogen fuel cells and electric trucks face challenges, innovations in infrastructure and vehicle design will be key to the success of Oregon’s long-term decarbonization strategy.

The impacts of major climatic events on urban vegetation cover are not well understood. We used Landsat 8 ETM + derived land cover in Google Earth Engine (GEE) to determine damage to urban vegetation, and Optimized Hotspot and Outlier Analyses to identify significant spatial clusters of hotspots and cold spots from Hurricane Michael in Panama City and Panama City Beach, Florida. We used two vegetation indices (Normalized Difference Water Index-NDWI and Enhanced Vegetation Index-EVI) to assess the impact of Hurricane Michael on urban vegetation cover. Results show that more than 30.07% of the land cover changed after two months of the hurricane landfall, including a rapid increase of 19.64% in water bodies. Overall, we observed a 4.91% decrease in vegetation cover, out of which 34.44% were coastal woody wetlands. NDWI showed a rapid increase due to an increase in water coverage in the study area, whereas EVI decreased due to vegetation loss by strong winds and intense precipitation. After Hurricane Michael, hotspots for high water content in sustained vegetation (NDWI) and overall vegetation condition (EVI) were discovered in Panama City Beach, Southport, and Youngstown CCD (census county division). Statistically significant (≥ 95% confidence, z ≥ 1.96) increases in NDWI hotspots (76.11% of the total area) were observed post-hurricane due to an increase in water bodies. EVI showed a decrease of about 9.21% in hotspot areas (≥ 95% confidence, z ≥ 1.96) due to defoliation caused by hurricane force winds. Our results highlight the advantages of using spatial statistical methods that could aid the development of natural hazard mitigation plans and risk reduction strategies by characterizing urban vegetation status in the Gulf Coast from previous hurricane occurrences spatiotemporally.

The production of biomass‐based sustainable aviation fuel (SAF) is gaining traction to reduce the carbon footprint of the aviation sector. We performed a techno‐economic analysis to estimate the break‐even price and life cycle carbon emissions of the SAF derived from carinata (Brassica carinata) in the Southeastern United States. Carinata has the potential as a feedstock for SAF production in the selected region due to higher yield, low fertilizer use, co‐product generation (animal feed, propane, and naphtha), and compatibility with current farming practices. The system boundary started at the farm and ended when the SAF is delivered to an airport. Without co‐product credit or other subsidies such as Renewable Identification Number (RIN) credit, carinata‐based SAF was more expensive ($0.85 L⁻¹ to $1.28 L⁻¹) than conventional aviation fuel ($0.50 L⁻¹). With co‐product credit only, the break‐even price ranged from $0.34 L⁻¹ to $0.89 L⁻¹. With both co‐product and RIN credits, the price ranged from ‐$0.12 to ‐$0.66 L⁻¹. The total carbon emission was 918.67 g CO₂e L⁻¹ of carinata‐based SAF. This estimate provides 65% relative carbon savings compared with conventional aviation fuel (2618 g CO₂e L⁻¹). Sensitivity analysis suggested a 95% probability that relative carbon savings can range from 61% to 68%. Our study indicates that carinata‐based aviation fuel could significantly reduce carbon emissions of the aviation sector. However, current policy support mechanisms should be continued to support manufacturing and distribution in the Southeastern United States.