Biomass is anything that is made of living or recently dead natural material. Biomass fuels can come in many different shapes and sizes.
These fuels are called biofuels and can be specially grown crops or can be stuff that we normally think of as waste: dead trees, tree branches, lawn clippings, wood, bark, sawdust from timber mills and animal poo.
One good thing about using this sort of waste is that instead of it being buried in rubbish dumps; this waste can be put to good use and turned into energy for electricity.
This works by putting this ‘waste’ in a furnace and burning it. The heat from this fire is used to boil water that creates steam, the steam spins turbines within power generators to create electricity.
When biomass is buried at a rubbish dump it decomposes releasing methane – a potent Green House Gas (GHG).
In some countries they put special pipes into rubbish dumps and collect the methane gas from the rotting waste underground and use it to make electricity.
A similar thing can be done with animals. As our hunger for all things meaty is on the rise we can capture the methane gas from the animal poo from farms and use that methane gas to make electricity. Some piggeries are now producing their own energy with surplus being sold back into the grid.
Another alternative is to attach (somewhat entertaining) giant air bags to the backs of cows to collect their recently farted methane. The poor cow in this picture has been fitted with a “Rectal Methane-Collecting Backpack” which collects methane that can be used to produce electricity.
While we’re on the subject of poo the same can be done at sewage treatment plants.
So with all this good news, how come biomass isn’t getting a better run? Why aren’t we using more of it? It is renewable and it stops methane gas reaching the atmosphere.
What are the problems with biomass and biofuels?
One problem with biofuels is that, growing crops for fuel requires a lot of land and water. These crops are also subject to the weather. Unlike other clean energy sources biomass is unpredictable as the crops have good and bad seasons.
Some farmers, attracted by higher prices, are swapping their food crops for fuel crops. This means that instead of growing crops to feed people they are growing crops to produce energy. This means there is not as much food for people. This is a contributing cause to food shortages in some parts of the world.
Using biomass to create energy has other challenges like increased pressure from loggers to burn more and more native forest ‘waste.’ What part of the forest is waste? What should stay in the forest to naturally decompose to enrich forest soils?
What is Australia doing about biomass and biofuels?
Biomass is mainly used in Australia for low cost heating, especially in households without access to natural gas for heating.
The wood that we use for burning in our fireplaces and in our pot-bellies (fireplaces, not our big tum-tum’s) is the main source of biomass energy in Australia.
Some companies do capture gas from landfill and sewage treatment sites. Australia currently has more than 65 sites using landfill gas to generate electricity, and a further 50 that operate away from landfill dumps.
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