Biomass / Ethanol / Biodiesel Webquest

Introduction

The eighth alternative energy source that we will consider is collectively represented by biomass, ethanol, and biodiesel.

Biomass is simply the weight of organic matter found in the bodies of all living organisms. Thanks to the high-energy carbon-carbon or carbon-hydrogen bonds found in carbohydrates, lipids, and proteins, organisms use their biomass as a reservoir of energy to drive the metabolic reactions that keep them alive.

Ever since primitive humans learned how to control fire, biomass in the form of wood has been used as a source of energy for heating and cooking. For millenia, people - especially in primitive cultures - have relied on wood that grows naturally or is cultivated for energy. More recently, people have learned that certain grasses and other herbaceous plants can be processed into pellets or briquettes.

Ethanol is a byproduct of the fermention of one form of biomass, specifically simple sugars like glucose or fructose. As noted in the overview presentation given on Wednesday, ethanol is an energy-rich substance that is viewed as a renewable energy, particularly as a fuel for cars and trucks.

Ethanol has been historically derived from grains like corn or from vegetative organs like sugar canes or sugar beets. More recently, people are looking at getting sugars from the decomposition of cellulose and other non-conventional plants. They briefly discussed their proposed process for cultivating and harvesting energy-rich plants for ethanol generating purposes.

A related form of energy is biodiesel, which is derived from chemically modified oils of plants, algae, and even animals. Biodiesel can be used to run conventional diesel engines, which normally burn fossil fuels. Biodiesel can also be used as a fuel to heat homes and even generate electricity.

Many people believe that biomass, ethanol, and biodiesel collectively hold great promise as viable sources of renewable alternative energy. They believe that they can be a central components of efforts to sharply reduce use of non-renewable fossil fuels. They envision extensive cultivation and processing of plants, and the establishment of an extensive distribution system for deploying biomass, ethanol, and biodiesel. Those people point to countries like Brazil that use ethanol to power a large proportion of their vehicles. Using ethanol, such countries successfully drastically reduce their dependence on oil - particularly from foreign countries. Advocates of ethanol say that we should follow the lead of countries like Brazil if we want to reduce the undesirable effects of powering our lives with fossil fuels. The federal govenment and many states provide subsidies and have developed other policies to promote biomass, ethanol, and biodiesel development. Likewise, many energy companies that once focused on fossil fuels are now turning to these alternatives.

Other people are more skeptical, pointing to several problems. First, they note that growing plants for energy puts a great deal of acreage into cultivation, and thus reducing the amount of natural lands that harbor biodiversity. Second, they express concern over the impact that cultivating plants for energy has on cultivation for food. They note that corn prices in particular have increased sharply due to dual demands. Third, skeptics point to concerns that cultivating, processing, and transporting biomass are themselves energy intensive. They assert that the energy derived from biomass, ethanol, and biodiesel requires nearly as much energy input from fossil fuels. Finally, critics of cellulosic ethanol claim that they process is still years away from implementation because critical enzymes needed to convert cellulose into sugars are not yet commercially available.

The purpose of this webquest is to enable teams of students to learn more about biomass, ethanol and biodiesel, and determine their potential to serve as significant sources of alternative energy in the future.