The Main Types of Biomass Energy
From a biological standpoint, biomass is defined as the total amount of living organisms in a given space at a given time. From an ecological viewpoint, however, biomass is also the amount of living material in a certain space at a certain time that can be used as a source of energy.
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Biomass has the fundamental advantage of being a renewable source of energy, as opposed to fossil fuels, which are only present in a limited amount on the planet. This is precisely why biomass energy is considered one of the most important alternative energy sources, alongside solar energy, hydropower and wind energy.
What is Biomass Energy?
Biomass energy is essentially the energy produced from organic matter that can be used either directly or in the form of biofuel. It all starts with photosynthesis, which is the main process used by plants to feed.
They are able to convert solar energy into chemical energy, which they later use as the main power resource for their internal processes. This chemical energy can be then used to produce the electrical energy that our society is so greatly in need of.
How does Biomass Energy work?
Plants store this chemical energy in the form of carbohydrates, such as sugar molecules and release oxygen into the environment as a waste product. When plants die or when they are burned, this chemical energy is released into the environment, and it can be used as power.
Fossil fuels generally employ the same process, as they are derived from biological matter as well and they release energy when they are burned. However, the main difference lies in the fact that it has taken millions of years for the fossil fuels to be produced, whereas biomass releases the energy it has stored throughout its lifespan. And this is exponentially shorter than that the amount of time necessary for the production of fossil fuels.
The process of getting energy from organic matter greatly depends on the type of biomass used. The main types are as follows:
- Natural – this type of biomass is produced without human intervention.
- Residual – this type consists of the biological remains from farming and various types of industries. A few examples are sawdust and wood pellets from the forestry industry, cereal straw, olive pits, almond shells, or corn stover from farming.
- Resulting from Energy Crops – this is the industrial growth of certain types of plants with the specific purpose of using them to obtain energy.
Furthermore, depending on the specific biomass material used to get the energy, the production process is different. We are going to tell you the most important aspects about each of these processes so that you can get an idea about the vastness of biomass use.
Wood, in all of its forms including logs, sawdust, wood chips, wood pellets and tree bark can be used to produce energy. These are the main processes used to obtain energy from wood:
This is the most widely used way of converting wood into energy. The process begins with burning the wood, in whichever form. The heat produced by combustion is then used to raise the temperature of the water inside a tank or a water boiler, which in turn releases steam. The steam can then be used to power a turbine, which in turn can power a generator that can produce electricity.
Wood combustion is frequently used in the forestry industry to get part of the energy necessary for the factory itself. Furthermore, the water boilers can be used to provide heat to the building by installing a piping system.
Commonly known as combined heat and power (CHP), cogeneration is defined as the simultaneous production of heat and electricity. While this system requires a substantially higher investment, it can produce considerably more energy than wood combustion. Moreover, the CHP system can use lesser wood to produce more energy and heat. A common mistake, however, is oversizing the system, as this usually results in higher costs rather than higher efficiency.
This energy production process entails heating up the wood to high temperatures in a chamber that is low on oxygen. Thus, carbon monoxide and hydrogen, which are pyrolysis gases are released from the wood, and they can then be mixed with oxygen and used to heat a boiler that then distributes the energy.
2. Agricultural Products
This category includes plant-based materials, both biological residue and energy crops. These are burned, and the heat is used to heat up a boiler. The steam produced by the boiler is then used to power a turbine and then a generator, which produces electrical energy. The entire system is similar to the one used for wood.
The agriculture industry can also put its waste to good use by employing it to produce part of the energy it needs. This is an extremely important aspect because it can reduce the overall costs of the entire industry.
3. Solid Waste
Garbage can be put to good use by burning it to produce energy. The system is essentially the same as the one described for wood combustion. However, there is a crucial difference. Not all garbage is biomass because quite a large part of it consists of plastics, which are petroleum-based. Thus, a considerable amount of the energy produced from garbage is not green energy.
The units that obtain energy from garbage are called waste-to-energy plants. While they are an extremely useful for getting rid of the enormous amounts of garbage produced by society, the process can have notable detrimental effects on the environment.
Biogas is produced by microscopic organisms, such as bacteria and fungi as they feed on dead plants and animals, as a waste product. The gasses generated through this process, particularly methane gas can then be used to produce energy because they are flammable.
Animal waste generates enormous quantities of methane gas, which can be harmful to the environment. As industrial farming has grown enormously in the last decades, the amount of methane gas released into the atmosphere has grown along with it.
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Therefore, current laws dictate that farms deposit the animal waste is special containers called digesters. By keeping the waste there for a longer period, a larger quantity of methane gas can be produced and instead of releasing it into the environment it can be directed through a piping system to an energy production plant.
Landfills are deposit sites for waste material that is buried in the ground. This method has been used to dispose of waste for very many years, and it is still quite common today. The buried waste produces biogas, which can be used for a constructive purpose by producing energy from it.
The process entails a piping system that is introduced into the landfill to release the gas, which is then burned to produce energy and heat. To get an idea about the size of this sector, you should know that in 2003, as much as 33% of the UK’s renewable energy has been produced from landfill gas.
6. Alcohol Fuel
Methanol, ethanol, propanol and butanol, the first four aliphatic alcohols, can be used as alternative fuels. Out of these four types, ethanol is by far the most accessible, because it can be produced in large quantities from fermenting plant-based material.
The starches and the sugars in these plants are fermented, and the ethanol is then obtained by distillation. It is the same process used to obtain the alcohol that we drink. But we need special types of plants and an elaborate process to produce alcoholic beverages. Industrial ethanol, on the other hand, can be produced from any plant that contains starch, sugars or cellulose.
Needless to say, industrial ethanol is not fit for human consumption, but since it is flammable, it can be used as fuel. Moreover, it is a superior to gasoline, which makes it one of the most important alternative fuel options.
Biodiesel is yet another central alternative fuel option. It is produced from alcohol and vegetable oil or animal oil. In fact, recycled restaurant oil is one of the most important sources of biodiesel. But what makes biodiesel truly impressive is that it can be used to power engines, either alone, as pure biodiesel (B100) or mixed with petroleum diesel in various ratios:
- 2% in B2
- 5% in B5
- 20% in B20
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Moreover, the engines that we use today are compatible with these types of fuels without any further modifications, which puts biodiesel among the top alternative fuels.
If you want to know more about biomass energy and biofuel, then you can read our in-depth article, All you need to know about Biofuel Energy. You can read all about the basics of the biomass energy productions and the most important biological materials used to obtain energy from.
Furthermore, you can read about the amount of pollution that biomass energy production generates, the impact it has on the environment and the socio-economic costs of producing it. The issue of whether or not biofuel energy is a valid replacement for fossil fuels is still under debate, as there are many issues yet to be clarified.