The Advantages and Disadvantages of Biomass Energy
To fully understand both the positive and negative aspects of biomass, we must first understand a little more about what Biomass Energy actually is.
Biomass is basically the term used to describe the components that make up organic plant matter – the physical parts of a plant or crop that you can touch and feel. In terms of alternative energy, biomass relates to organic products which can be converted into a fuel source to create energy. These kinds of energy fuels are commonly called “biofuels”.
Organic matter that’s grown specifically to be used to create energy are called “dedicated energy crops”. Because of the enormous potential of this energy source, these biofuels are constantly talked about in the media and millions of dollars are being pumped into their research and production each year.
Biomass products and matter using in the production of biomass energy typically include the following: agricultural waste and related crops, animal and domestic wastes, aquatic, peat based and moss type plants, wood and related wood waste.
These materials account for three main biomass energy sources;
- Liquid fuels – such as biodiesel and ethanol used in transportation.
- Solid biomass – such as wood which is used in incineration to generate heat.
- Gaseous fuels – methane and other combustable gases for cooking and heating.
Photosynthesis
All plant matter grows by carrying out a process known as photosynthesis. In basic terms, the cells of a plant that make up the green parts – such as leaves, absorb carbon dioxide from the air around them. They then convert this into sugars and carbohydrates, excreting oxygen as a waste product.
As well as providing the vital oxygen that we need to breathe, this also has the effect of removing the greenhouse gas carbon dioxide from the atmosphere. Because of this, biomass materials and crops are virtually always carbon neutral, at the very least carbon negative.
Using Biofuels as an Alternative Energy Source
Biomass, and therefore biofuels, can be used to create alternative energy in a number of different ways. Virtually any organic matter that has the ability to be burned can be created into a biofuel of some kind. Using biochemical methods, raw biomass is transformed into either: Biodiesel, Biogas, Bioethanol and Biofuels to name a few.
Electrical energy can be generated by burning biofuels over a heat source – a process known as combustion. This creates steam, which is used to power turbines that generate electricity. Whilst using biofuels in isolation to create electricity is possible, it is often mixed in conjunction with fossil fuels such as coal – a process known as co-firing, to reduce the amount of fossil fuels burned.
Co-firing involves a mixture of both biofuels and fossil fuels being mixed together and burned over a heat source. This process of combustion fuels the turbines that create electricity. Co-firing decreases the use of fossil fuels in such electricity power plants, as well as helping reduce the amount of greenhouse gases emitted directly into the atmosphere.
Advantages of Biomass Energy
There are many good points to take into account when considering biomass energy as an alternative fuel source. It is a completely renewable energy source. As crops and plants are harvested for use, so more can be planted. Growing plants use photosynthesis – a process that actively removes carbon dioxide from the atmosphere.
Biomass waste products are also readily available. This prevents them going into landfill and polluting the surrounding earth and water supplies. Co-firing reduces the effects of smog and acid rain, as well as reducing the greenhouse gases emitted. Also the use of biofuels whether for heating, burning or transportation decreases our need to import expensive foreign fuels, such as oil and gas.
Disadvantages of Biomass Energy
There are, however, a few negative aspects that have yet to be overcome in relation to biomass energy. Pound for pound, biomass energy has less energy content and is nowhere near as productive as conventional fossil fuels. This is because oil, coal, and gas are the product of millions of years of forming deep in the ground, creating super fuels that produce an amazing amount of energy in ratio to the amount used. However, fossil fuels are rapidly running out, and are not something which can be easily replaced.
Because of the relative inefficiency (in comparison to fossil fuels) of biomass energy, large amounts of land is required in order to grow these dedicated energy crops. This means that they take up valuable land that could instead be used for agriculture or human food production. The cost of producing biomass energy can be prohibitive. It is expensive to produce, compared to the quantity of energy they it yields.
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