How Does Biomass Work?

What is Biomass?

Biomass is any organic material that is made by plants animals. Examples of biomass are wood, leaves, grass, and all vegetation, animal flesh and manure. Today when people refer to biomass they are usually referring to biofuel which is biomass  used as a source of energy.

Fossil fuels are believed to be the remains of ancient plants and animals so technically they are biomass too. But the term biomass typically refers to materials from plants and animals that are living now or that were living recently.

How Biomass is Created

Biomass is made from plants and is essentially a form of solar energy. Plants absorb energy from the sun as they grow through the process of photosynthesis. Plants use the sun’s energy to break carbon dioxide and water molecules apart into their basic elements, hydrogen carbon and oxygen. The hydrogen and carbon are used to build the molecules that the plants are made of. Most of the oxygen is released back into the atmosphere.

How Biomass Energy is Used

This energy is released when the molecules in the plants are broken down by burning or digestion. In both of these processes the hydrogen and carbon bond with oxygen from the atmosphere in a chemical process that produces heat.

Your own body depends on biofuel. The food you eat is a biofuel that your body breaks down and extracts energy from. Humans have also learned to extract biofuel in other ways. The most common way is to burn it with fire which releases the energy as heat. This heat can be used directly for warming or can be converted to other forms of energy such as electricity. Electricity is usually generated by heating water to produce steam that turns a turbine generator.

Biomass can also be converted to other forms of  biofuel like alcohol or biodiesel. These fuels van be used to power cars and other machinery that typically run on petroleum fuels like gasoline and diesel. This is usually an energy intensive process that consumes a lot of energy just to transform the fuel. For this reason these kind of fuels have not proven themselves to be competitive with other fuels that are available like petroleum.

Advantages of Biomass as a Fuel

Biomass is renewable, plants continue to producing more. There are massive amounts of biomass that are a waste product from agriculture and forestry that are typically discarded and go to waste. This material could be used as a source of energy.

A domestic source of energy that is not dependent on other countries and are less effected by political instability than petroleum.

Biofuels are often from local sources so less expense and energy is consumed transporting them vs. other fuels that may have had to be shipped from thousands of miles away.

Disadvantages of Biomass as a Fuel

Biomass can be more expensive than other fuels especially when converted to other types of fuel like alcohol, biodiesel or electricity.

Growing crops for biofuel may use land and resources that could be used for growing food. There could be potential for this to lead to higher prices for food and even food shortages.

Growing crops for biofuel can displace wildlife habitat and lead other land use problems. An exception to this exists with extracting forest biofuels that can enhance wildlife habitat.

Advantages of Forest Based Biofuels

A major advantage of forest based biofuels is they can be extracted while maintaining a natural healthy native habitat. The responsible harvest of timber and other forest products can be sustainable and co-exist with a healthy forest ecosystem. Forest projects such as thinning and fuels reduction enhance forest health and help protect them from wildfire.

All of these forest activities produce massive amounts of biomass waste. Waste products like sawdust and other wastes produced in lumber mills are used and some of it us used as biofuel. But this is only a small fraction of the amount of biomass that is left on the forest floor to rot or is piled and burned. It will likely be only a matter of time before the forest products industry starts utilizing more this resource.

One of the most practical uses for forest biomass is making wood pellets for direct heating.