Bioenergy is renewable energy produced from biomass, an organic material that can be used to generate heat, transportation fuel, and electricity. Bioenergy is considered a renewable energy option because, unlike coal and gas, organic plants and animals can be easily regenerated.
Woody biomass is traditionally used to generate bioenergy. However, advances in technology have expanded the potential resources to include oilseeds, algae and agricultural residues.
How do you generate energy from biomass?
There are three processes that convert organic matter into energy.
- Chemicals – Use chemicals to break down substances and turn them into liquid fuels. An example is corn ethanol, a liquid fuel made from corn.
- Thermal – The main methods of heat–heat conversion are combustion in excess air, gasification in reducing air (reaction of matter at high temperatures without combustion), and pyrolysis in the absence of air (by heating chemical breakdown of a substance into one or more usable substances). air.
- Biochemistry – Using microorganisms, enzymes and bacteria to break down organic matter into liquid or gaseous fuels.
The method used depends on the type of biomass. For example, dry feedstocks are burnt in furnaces, while wet feedstocks are left to rot in sealed tanks where they create biomethane gas.
Bioenergy accounts for almost a tenth of the global primary energy supply
According to the International Energy Agency (IEA), bioenergy accounts for approximately roughly 9% of world total primary energy supply. The IEA says that more than half of this “relates to the traditional use of biomass in developing countries for cooking and heating, using inefficient open fires or simple cookstoves with impacts on health (e.g. due to indoor smoke pollution) and the environment.”
Environmental impact
Plants that are the source of biomass capture a nearly equivalent amount of CO2 through photosynthesis while they are growing (which can make biomass a carbon-neutral energy source). However, environmental organizations such as Greenpeace have raised concerns about the impact of forest bioenergy.
“Using forests to produce energy is like pouring gasoline to put out a fire” said Larry Edwards, a Greenpeace-US forest campaigner. “Science shows that it can take decades for new trees to absorb the carbon produced when burning wood in existing forests.”
In addition, there are concerns that cutting trees for energy production is more advantageous than cutting whole trees, as any part of the tree can burn. Whole tree felling removes more nutrients and soil cover from the site than conventional felling, which can adversely affect the long-term health of forests.
