Biomass Energy, sounds familiar? No? Then this article is for you. Biomass energy has been used by early men for heat generation in the form of firewood and is now being used worldwide for the purpose of electricity generation, and creation of biofuels (methane) for power generation.
What is Biomass?
The term “Biomass” is used to refer to remains from living or recently living organisms (such as plant materials and animal wastes) that are used in the generation of energy. Biomass materials are completely organic materials and these materials do not just provide a means of energy generation but a clean, sustainable and renewable fuel as well.
Some examples of Biomass materials, also known as biofuel feedstock, suitable for generation of biomass fuels are scrap wood, straw, forest debris, animal manure, food wastes etc.
What is Biomass Energy?
Biomass Energy is a renewable form of energy gotten from living organisms or organisms that once lived. How then does this energy get into these organisms in the first place? Biomass stores chemical energy gotten from the sun. Plants capture produce energy through the process of photosynthesis and stored biomass energy can be converted into other forms of energy such as biofuels, syngas etc (indirect usage) or used directly as a source of heat energy.
How can collected biomass be converted to energy?
There are four major ways through which biomass can be converted into various forms of energy:
Direct combustion is simply burning collected biomass directly for the purpose of heat generation. This method is still being used in developed and developing countries till today for the purpose of cooking, heating, and even just for keeping warm during the winter or rainy seasons.
Thermochemical conversion is a chemical process accompanied with lots of heat! Biomass is subjected to severe temperatures and the resulting products are collected and processed to yield one form of energy or the other.
Thermochemical conversion can be divided into:
- Pyrolysis: Pyrolysis involves the subjection of biomass to a temperature range of 200°C-300°C. This process is carried out in the absence of oxygen which prevents combustion and alters the chemical properties of biomass resulting in the production of pyrolysis oil, syngas and solid biochar. Pyrolysis oil, or bio-oil, can be combusted for the generation of electricity.
- Gasification: This process is similar to pyrolysis. The only difference is the fact that biomass energy is generated by exposing biomass to temperatures above 700°C with controlled exposure to oxygen. The end product of gasification of biomass is mostly syngas. Syngas can be used to power diesel engines, fuel engines and when heated it is heated to generate steam in a turbine which in turn powers a generator (steam generator) which outputs electricity.
Syngas can also be broken down to release hydrogen. Hydrogen collected from syngas can be burned also to generate heat or can be used as a form of clean fuel to power fuel cells and engines.
Chemical conversion of biomass involves a process known as transesterification; a process involving the conversion of animal fats, vegetable oils and grease into fatty acid methyl esters which in turn is converted into biodiesel.
Biomass energy stored in biodiesel gotten from the process explained above can be used directly in engines since its composition is similar to regular diesel.
Biological conversion of biomass into biomass energy utilizes a process known as anaerobic digestion, the natural biodegradation of biomass in the absence of oxygen. Anaerobic digestion could happen indirectly in landfills or could be deliberately done to generate methane/biogas.
Algae, yes, that greenish slimy organism, is highly concentrated with carbohydrates, oils and proteins gotten from photosynthesis. These oils when harvested, can be converted to biodiesel and even bioethanol, in essence, biomass energy. Compared to other biomass (plants scraps in particular such as tree remains) algae takes up less space to grow.
What Are The Pros and Cons Of Biomass Energy?
Pros / Merits
- Biomass energy is sustainable.
- With the constant supply of waste from construction activities, wood waste from paper and pencil making, landfills, Biomass energy is renewable.
- Biomass energy can be recombined with other forms of energy to increase efficiency.
- Biomass energy produces by-products that find use in the agricultural sector.
- Algae biomass can grow in confined spaces and in no time.
- Waste reduction as waste is channeled to biomass energy.
- Biomass provides a form of energy storage.
Cons / Demerits
- Biomass feedstock face the risk of exhaustion if they are not replaced as much as they are consumed.
- The energy density of biomass is lower than that of fossil energy. Although methods to maximize efficiency have been put in place now.
- Biomass under combustion releases gases such as CO, CO2, NO and these gases have to be trapped as soon as they are released or else sustainability levels would drop.
- High costs may be encountered.
- Biomass process requires lots of space.
How much energy does biomass produce?
Biomass energy in the year 2020 yielded, in the U.S alone, 4.5 quadrillion Btu, supplying 4.9% of U.S primary energy consumption. A rule of thumb is that for every 1 ton of dry wood you get 1MW/hour and for every 2 tons of green wood, 1MW/hour is gotten.
How can efficiency of biomass energy be increased?
Biomass has been proven to have at least 50% moisture content averagely and if this moisture content can be reduced, biomass efficiency increases. To increase this efficiency natural methods of drying or terrafaction can be used to reduce moisture content of biomass.
The efficiency of biomass energy essentially depends on the energy content in biomass feedstock. Some biomass would have high heating value while some would have a low heating value. Biomass with high heating value would give higher efficiency. High heating value depends also on the moisture content. A low moisture content = high energy level = high efficiency and vice versa. In other words, the dryer the biomass feedstock is, the higher its efficiency.
What Countries are Using Biomass Energy Currently?
The top 10 countries harnessing biomass energy in form of direct combustion now are Ethiopia, DR Congo, Tanzania, Nigeria, Haiti, Nepal, Togo, Mozambique, Eritrea and Zambia.
The top 10 countries harnessing biomass energy in form of biofuels and biofuel productions in Petajoules are United States, Brazil, Indonesia, Germany, China, Thailand, France, Netherlands, Spain and Argentina.
What Percent of the World Consumes Biomass Energy?
Around 7.5% of the world uses and consumes biomass energy.
How Green is Biomass Energy?
You might want to argue that using biomass and biomass energy releases stored carbon back to the atmosphere. And guess what, you might be right, but see it this way. When most biomass sources (for example trees) die, they rot out and CO2 previously stored in them is given off to the atmosphere. So, instead of just giving off this carbon, the idea of biomass collects this carbon and first uses up stored energy before giving it out. Advances in technology can now prevent direct release of carbon to the atmosphere during consumption of biomass energy.
How Much Does Biomass Energy Cost?
Estimations of biomass energy depends on the form of bioenergy and the method of conversion employed. Bioenergy costs USD 0.062/kWh in China, USD 0.079/kWh in Europe, USD 0.057/kWh in India and USD 0.097/kWh in North America. Individually projects to generate electricity can cost between USD 0.030/kWh to USD 0.250/kWh.
Can Biomass Generate Electricity?
Yes. Biomass can be used to generate electricity.
Biomass energy has been used as a primary source of heat and can now be channeled towards generation of electricity which is one of the basic amenities in developing countries.
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