9781422285619

14 Renewable Energy

Using Biomass: Burning Plants gain energy from the sun through a process called photosynthesis. This stored- up solar energy can be released to create electricity, fuel, or heat. There are several methods of converting biomass into energy. Burning, also called direct combustion , is the most basic. The steam produced by direct combustion can power turbine generators that produce electricity. This does not have the environmental impact of burning fossil fuels such as coal, which is frequently how electricity is generated today. However, biomass has to be either found or grown before it can be burned. Clearing land to grow biomass material, as well as the harvesting process itself, can result in excessive carbon pollution. It can also be bad for overall forest health if forests are not managed well. Sometimes biomass is mixed with coal and burned in a method known as co- firing. Energy experts advocate this as a good way of “transitioning” into biomass alternatives. Using Biomass: Other Methods In the fermentation process, biomass is converted to alcohol with the addition of yeast, enzymes, or bacteria. When these are introduced, they act on the sugars in the biomass products to create ethanol and carbon dioxide. After the ethanol has been purified, it can be used as automotive fuel. Gasification is a means of heating biomass in special low-oxygen environments so that it breaks down into its base components of solids, liquids, and gases. These Bioplastics Some plastic products are now made of biomass sources. Called bioplastics, they are derived from such materials as potato starch, soy protein, vegetable oils, and other renewable resources. Many are able to biodegrade after they are used, which means they break down naturally into the environment, rather than staying intact in landfills. Bioasphalt is a related technology in which road coverings are made from starches, cellulose, and even sugar or molasses.