Solutions to the Gas Problems: Biobutanol and Biogas

Butanol is a 4-carbon alcohol (butyl alcohol). Biobutanol is butanol produced from biomass feedstocks. Currently, butanol's primary use is as an industrial solvent in products such as lacquers and enamels. Biobutanol can be an alternative fuel. Like ethanol, biobutanol is a liquid alcohol fuel that can be used in today's gasoline-powered internal combustion engines. The properties of biobutanol make it highly amenable to blending with gasoline. It is also compatible with ethanol blending and can improve the blending of ethanol with gasoline. The energy content of biobutanol is 10 to 20 percent lower than that of gasoline.

The benefits of biobutanol are similar to the benefits of ethanol. It can be produced domestically from a variety of homegrown feedstock crops while creating U.S. jobs. Greenhouse gas emissions are reduced because carbon dioxide captured when the feedstock crops are grown balances carbon dioxide released when biobutanol is burned. In addition, biobutanol is easily blended with gasoline for use in today's gasoline-powered vehicles. Biobutanol proponents claim that gasoline-powered vehicles can be fueled with biobutanol as an alternative fuel (blends of 85 percent or more biobutanol with gasoline) with minor or no vehicle modifications, although testing of this claim has been limited.

Another emerging alternative fuel is biogas. Biogas is the gaseous product of the anaerobic digestion (decomposition without oxygen) of organic matter. It is typically made up of 50-80% methane, 20-50% carbon dioxide, and traces of gases such as hydrogen, carbon monoxide, and nitrogen. In contrast, natural gas is typically made up of more than 70% methane, with most of the rest being other hydrocarbons (such as propane and butane) and only small amounts of carbon dioxide and other contaminants. Biogas is sometimes called swamp gas, landfill gas, or digester gas. When its composition is upgraded to a higher standard of purity, it can be called renewable natural gas.

Biogas is used for many different applications worldwide. In rural communities, small-scale digesters provide biogas for single-household cooking and lighting. China alone is estimated to have 8-17 million of these systems. Large-scale digesters provide biogas for electricity production, heat and steam, chemical production, and vehicle fuel. In 2003, the United States consumed 147 trillion BTUs of energy from landfill gas, about 0.6% of total U.S. natural gas consumption.Biogas once upgraded to the required level of purity (and compressed or liquefied), it can be used as an alternative vehicle fuel in the same forms as conventionally derived natural gas: compressed natural gas (CNG) and liquefied natural gas (LNG). The benefits of biogas are similar to the benefits of natural gas: increasing energy security, paving the way for fuel cell vehicles, and improving public health and the environment through reduced vehicle emissions.