Overview

Burning coal, oil, and gas inevitably produces carbon dioxide, a key greenhouse gas, as well as other pollutants, including acid-rain-related gases. By contrast, growing and burning energy crops is greenhouse gas neutral, as long as the regrowth rate balances the use rate, so that as much carbon dioxide is absorbed as is produced by combustion.

Crops have essentially many functions and benefit particularly for the human animal! Their products are not only a primary source of human food and animal feed, but also as source of timber, fiber, and biomass energy (BioCap Canada, 2004). In addition, crops have also an essential function to maintain ecological systems and natural environment.

Grain crops include corn, wheat, rice, barley, and other cereals. The seeds of these plants are typified by their high starch content that can be hydrolyzed to fermentable sugars for ethanol production. The sugar crops, including sugar cane, beet, and sweet sorghum, are preferable to the starch crops to the extent that sucrose is more readily hydrolyzed to fermentable sugars. However, sugar cane production is restricted to warm climates, and requires both high-quality land and irrigation. Sweet sorghum has considerable advantages over sugar cane as an energy crop. It can grow in a variety of soils and climatic conditions and its production costs have been estimated to be just over half those for sugar cane.

Most of crop production is used as foods and the concern is that biofuels can consume these crops. However, more crops are...