Biomass Energy

What is Biomass?

In short, biomass is any plant or animal material that is used to create energy. There are 6 general types of biomass and they are agricultural crops & residue, forestry crops & residue, animal residues, industrial residues, municipal solid waste, and sewage.

▲Diagram of Biomass Sources [11]

How is Biomass Used?

Biomass like in the previous explanation, is used to create energy. There are 3 ways in which biomass are converted into energy: burning to create heat, converted into electricity, or processed into biofuel.

Conversion by Burning

When biomass is converted into energy via heat, it needs to go through a process called torrefaction. During torrefaction, biomass is heated to 200˚~320˚C to completely dry the biomass. The biomass is dried to an extent that it loses the ability to absorb moisture or rot. The biomass loses 20% of its original mass but 90% of its original energy is retained. The dried biomass is then compressed into briquettes. The briquettes are then burnt to create steam and turn turbines for electricity.

Pyrolysis

There is similar process called pyrolysis in which biomass is heated to 200˚~300˚C without the presence of oxygen. This allows the biomass to be chemically altered without combusting. Pyrolysis creates pyrolysis oil, syngas, and biochar. Pyrolysis oil is a type of tar and is burnt to turn turbines. It can be used to make plastics and some scientists speculate that it can be an alternative for petroleum. Syngas is a synthetic gas (CO + H2) that is convertible to methane gas and can be used as a replacement for natural gas. If this syngas is cleaned of its impurities, it can be burnt for electricity or transformed into biofuel, chemicals, and fertilizer. Biochar is a type of charcoal that is particularly useful in agriculture. It is a carbon-rich solid that can be used as a fertilizer (can retain water and nutrients) and functions as a carbon sink and prevents runoff.

▲Pyrolysis Oil [8]

▲Biochar [7]

Gasification

Another process is gasification in which biomass is heated to more than 700˚C with a controlled amount of oxygen. This creates syngas and slag. Slag is a glassy molten liquid that can be used to create cement and asphalt.

Anaerobic Decomposition

There is also the Anaerobic Decomposition in which microorganisms break down biomass in the absence of oxygen. This process can be used in landfills where biomass is compressed and creates a partially anaerobic environment. It can also be used in farms with animal manure. Anaerobic Decomposition creates methane which can be burnt.

Black Liquor

During the process in which wood is processed into paper, black liquor is created. Black liquor retains 50% of the wood’s biomass energy. Until the 1930’s it was considered a waste product, but after the invention of a way to use this black liquor as a power source to run their mills, this forest industry became the most energy-efficient  industry.

▲Black Liquor [9]

Biofuel

Biomass can be converted into biofuel which is either ethanol or biodiesel. Ethanol is created from the fermentation of crops rich in carbohydrates. Biofuel is a combination of ethanol with animal fats, recycled cooking fat, or vegetable oil. Biofuels cannot operate as efficiently as gasoline, but have significantly smaller greenhouse gas emissions. Ethanol can be used instead of wood in residential fireplaces. Ethanol when burnt, releases heat and water vapor instead of smoke.

Algae Fuel

▲Algae Farm in Oman [10]

Algae is especially focused on as a renewable biomass, as it requires far less resources to produce and photosynthesizes at a faster rate than other food crops (30 times faster). It also doesn’t require fresh water as it grows in salt water. It is estimated that 38,850 square kilometres (half of the state of Maine) are enough to replace all petroleum fueled energy in the U.S. When carbon dioxide is filtered through an algae pool, it absorbs much of the carbon dioxide acting as an excellent filter.

[1] Andrew Turgeon, Elizabeth Morse. 2012. “Biomass Energy”. National Geographic. https://www.nationalgeographic.org/encyclopedia/biomass-energy/. 2020/02/14.

[2] 2015. “Biofuels 101”. Student Energy. https://www.youtube.com/watch?v=ZGmwtDffc74. 2020/02/14.

[3] Kevin McFarland. 2017. “Biomass Advantages and Disadvantages”. SynTech Bioenergy. https://www.syntechbioenergy.com/blog/biomass-advantages-disadvantages. 2020/02/14.

[4] Akane Okutsu. 2018. “Jet biofuel mass production to begin in Japan”. Nikkei. https://asia.nikkei.com/Business/Companies/Jet-biofuel-mass-production-to-begin-in-Japan. 2020/02/14.

[5] 2016. “Biomass Conversion”. U.S. Department of Energy. https://www.energy.gov/sites/prod/files/2016/07/f33/conversion_factsheet.pdf. 2020/02/14.

[6] Salman Zafar. 2020. “Biomass Energy in Jordan”. EcoMENA. https://www.ecomena.org/biomass-energy-jordan/. 2020/02/14.

[7] “Aries Green Biochar”. HomeDepot. https://www.homedepot.com/p/ARIES-CLEAN-ENERGY-Aries-Green-Biochar-Biochar5/311286093. 2020/02/14.

[8] “Pyrolysis Oil”. indiamart. https://www.indiamart.com/proddetail/pyrolysis-oil-13784190333.html. 2020/02/14. 

[9] Philippe Crowe. 2012. “Black Liquor to Fuel Trucks?” hybridCARS. https://www.hybridcars.com/black-liquor-fuel-trucks-46633/. 2020/02/14.

[10] 2019. “UK firm said to plan $440m algae farm in Oman”. Waleosb Group. https://www.waleosb.com/2019/05/17/uk-firm-said-to-plan-440m-algae-farm-in-oman/. 2020/02/14. 

[11] “Status Quo and Development of Biomass Energy in China”. AGICO GROUP. http://www.agicosolution.com/biomass-energy-in-china/. 2020/02/14.

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