Assessing land and water required for realizing the renewable fuel mandates in the United States
Abstract
The Renewable Fuel Standard (RFS), a U.S. federal program, has posed a mandate of renewable fuel use (i.e. 36 billion gallons by 2022, of which at least 44% is advanced biofuel such as that from cellulosic feedstock); however, the RFS mandates will have to be postposed given the large gap between the advanced biofuel production and the RFS targets since 2015. This can be attributed to a variety of factors, such as a lack of private investment, limited federal assistance, technology setbacks, lack of supporting infrastructure, and insufficient resource availability. This study focuses on the assessment of land available for advanced biofuel feedstock (e.g. energy grasses such as Miscanthus and swithgrasses) production and water available for biofuel refinery, based on which, the vulnerability of the RFS due to spatially varied land and water limitation is mapped and the RFS mandate feasibility is assessed in the Contiguous U.S. (CONUS). One of the major concerns for biofuel development is the land required for biomass production, which competes with food crops. To ameliorate the conflicts among food production, biofuel production and the environment, scientific and policy communities have proposed to use marginal agricultural land to plant perennial energy grasses. Marginal land has low inherent productivity for agriculture and is high-risk for the environment. Using a machine learning approach, this study provides an estimate of the marginal land in the CONUS, with a resolution of ~250 m. Based on the estimated land and an average yield of some typical perennial energy grasses, the biomass production with the same spatial resolution as land identification is calculated. Next, the refinery plants, including the location and capacity, are projected within the CONUS based on the biomass availability and water availability for refinery processing. Following exiting assessment of water available for additional development across several hydrologic response units (HUC 8 - HUC 4) and the current water uses at the county level, potential water deficit in each of the defined refinery planning units within the CONUS is estimated. It is found that the water constraints across the country can cause a significant reduction of renewable fuel production required for the RFS mandates.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMGC066..01C
- Keywords:
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- 1630 Impacts of global change;
- GLOBAL CHANGE;
- 1817 Extreme events;
- HYDROLOGY;
- 1834 Human impacts;
- HYDROLOGY;
- 1880 Water management;
- HYDROLOGY