Use this interactive map to compare biomass feedstocks and biofuels by location and calculate the biofuels potential for a given area.
Almost any plant-based material can be an ethanol feedstock. All plants contain sugars, and these sugars can be fermented to make ethanol in a process called "biochemical conversion." Plant material also can be converted to ethanol using heat and chemicals in a process called "thermochemical conversion" (see Ethanol Production to learn more about these processes).
Some plants are easier to process into ethanol than others. Some don't require many resources to grow, while others need many resources, as well as intensive care. Some plants are used for food as well as fuel, while others are cultivated exclusively for ethanol. Even plant-based wastes can be made into ethanol. Climate and soil type determine the types and amounts of plants that can be grown in different geographic areas.
The U.S. Department of Energy's Bioenergy Technologies Office Billion-Ton Update provides extensive information about existing and potential feedstocks and availability at various price points. To learn more, see National Renewable Energy Laboratory's Biomass Maps or use BioFuels Atlas.
Starch- and Sugar-Based Ethanol Feedstocks
Nearly all ethanol is derived from starch- and sugar-based feedstocks. The sugars in these feedstocks are easy to extract and ferment, making large-scale ethanol production affordable. Corn is the leading U.S. crop and serves as the feedstock for most domestic ethanol production. Small amounts of wheat, milo and sugarcane are used, although the economics of these are not as favorable as corn. The Renewable Fuel Standard limits production of ethanol from starch-based feedstocks to 15 billion gallons to ensure there are enough feedstocks to meet demand in livestock feed, human food, and export markets.
Cellulosic Ethanol Feedstocks
Cellulosic feedstocks are non-food based feedstocks that include crop residues, wood residues, dedicated energy crops, and industrial and other wastes. These feedstocks are composed of cellulose, hemicellulose, and lignin (typically extracted to provide process steam for production). It's more challenging to release the sugars in these feedstocks for conversion to ethanol. Commercialization of these processes is a funding priority of the U.S. Department of Energy's Bioenergy Technologies Office.
Cellulosic feedstocks offer many advantages over starch- and sugar-based feedstocks. They are more abundant and can be used to produce more substantial amounts of ethanol to meet U.S. fuel demand. They are waste products or, in the case of trees and grasses grown specifically for ethanol production, can be grown on marginal lands not suitable for other crops. Less fossil fuel energy is required to grow, collect, and convert them to ethanol, and they are not used for human food. There are challenges with harvesting, collecting, and delivering cellulosic feedstocks. Researchers are studying these challenges in an effort to formulate solutions to them.
To determine the potential gallons of ethanol produced (via biochemical conversion) per ton of various feedstocks, use the Theoretical Ethanol Yield Calculator and the Biomass Feedstock Composition and Property Database. The Energy Research Centre of the Netherlands' Phyllis database also contains information on the composition of biomass and waste. The table below shows the potential of some commonly considered feedstocks.
|Feedstock||Theoretical Ethanol Yield
(gal/dry ton of feedstock)
|Cotton Gin Trash||56.8|