Bioenergy

The Ararat Rural City Council and the Victorian Department of Sustainablity and Environment through the Sustainability Accord Program have developed this web site and the Bioenergy Support Program to assist individuals and businesses become more sustainable by using bioenergy.  Council’s Bioenergy Support Officer is available to provide advice and support for people wanting to explore bioenergy options. Council also has a portable gasifier unit and a biochar unit which are available for demonstrations to interested groups and organisations.

What is bioenergy?

Bioenergy is renewable energy produced from biological material. Humans have used bioenergy for thousands of years in the form of wood fires.  Other basic types include vegetable oils as well as animal fats, oils, bone and dung.  It is still the primary energy source for millions of people around the world. 

Unlike fossil fuels (coal and oil) bioenergy is renewable because it comes from organic material, usually referred to as biomass, which has recently stored sunlight in the form of chemical energy.  Plants store energy from sunlight in a process called photosynthesis.  Sunlight, water and carbon dioxide are combined within green plants to form simple sugars which the plant uses to grow.  The cellulose in the leaves and stems is how this energy is stored. 

When biomass is burned the process is reversed and the carbon dioxide together with water vapor and energy in the form of heat is released.  When plants are regrown, as with crops, the carbon dioxide is reabsorbed by the growing plants and the cycle continues.  In this way bioenergy is renewable because the carbon is recycled and does not add to atmospheric carbon dioxide.

Types of bioenergy

There are two basic sources of bioenergy - biomass and biofuel.

Biomass is the generally solid organic material used for production of heat and electricity

Biofuel is usually liquid transport fuel derived from plant material, vegetable oils and animal fats but may also include biogas (methane) processed for use in gas powered vehicles.

As a fuel, biomass may include wood, wood waste, straw, manure, sugarcane, and many other byproducts from a variety of agricultural processes.  One of the advantages of biomass fuel is that it is often a by-product, residue or waste-product of other processes, such as farming, animal husbandry and forestry.  In theory this means there is no competition between fuel and food production, although this is not always the case.

Biomass is often used for home heating by burning the material open fires, heaters and stoves.  It can also be used for heating larger buildings through boilers.  Electricity can be produced from biomass via combustion in steam boilers or Sterling Engines or via gasification.  Gasification can be through anaerobic digestion to produce biogas or a type of incomplete combustion process which produces a gas called syngas.

Biofuels can be a substitute for petroleum products and are produced by fermenting plant material like sugar cane, wheat, corn, sugar beet to produce ethanol.  Vegetable oils from canola, rapeseed and Oil Palms or animal fats like tallow are processed into a diesel substitute called biodiesel. In a number of European countries methane from anaerobic digestion of biomass is refined into a substitute for Compressed Natural Gas (CNG) and used as a transport fuel.