Energy is indispensable in our modern society. It is needed heating in our homes, fueling our cars, growing our food, and operating our businesses. It is also one of the most important inputs to economic and social development.  Energy is at the root of many local and global problems. Energy-related problems include climate change, domestic energy security, and lack of affordable energy sources in developing countries. 

Most of our energy comes from burning fossil fuels like petroleum and coal, which are depleting daily.  At present, approximately 87% of energy demand is satisfied by energy produced through fossil fuels. We need new energy sources to replace fossil fuels that we currently use.  A number of renewable resources like solar, wind, hydropower, geothermal, and biomass have the potential to transform energy supply for the better. These energy sources are called “renewable” because they never run out. A number of renewable resources like solar, wind, hydropower, geothermal, and biomass have the potential to transform the U.S. energy supply for the better. These energy sources are called “renewable” because they never run out. Renewable energy accounts for 33 percent of the global energy consumption. One of the most promising renewable energy sources for is biomass [1].

Concept of Bioenergy

Bioenergy is a form of renewable energy that is derived from biological sources including biomass. Biomass is an organic source that includes materials such as agriculture residues, energy crops, wood, wood waste, and algae. At this time, wood is perhaps the largest biomass energy resource. Strictly speaking, biomass encompasses all living things.  It can be converted into liquid transportation fuels, heat, electricity, and products. It is a versatile energy resource like petroleum. There are three ways to harvest the energy stored in biomass to produce biopower: burning, bacterial decay, and conversion to a gas or liquid fuel [2].          

Bioenergy is a synonym to biofuel, which is fuel derived from biological sources. Modern bioenergy is widely used for space and water heating. A major advantage of bioenergy is that it dramatically reduces the net gain of carbon dioxide (CO2).  In order to keep global warming below 2 degrees Celsius, greenhouse gas emissions have to be drastically reduced.  Bioenergy is considered an effective way to mitigate greenhouse gas (GHG) emissions.As consumers of energy, farmers can produce and utilize bioenergy at their farm. Beside some financial benefits, the farmers’ standard of living increases significantly. Some agricultural products  are grown by farms specifically for  biofuel production. These include soybeans, corn, and sugar cane.

Biomass is the only renewable energy source that is not freely available.  To produce itrequires a long chain of activities such as planting, growing, harvesting, pre-treatment (storage and drying), upgrading to a fuel, and finally biological conversion to an energy carrier. It is very difficult to generalize bioenergy costs due to its complex characteristics [3]. Three major international organizations advocate for various bioenergy policies [4]. International Energy Agency (IEA), Intergovernmental Panel on Climate Change (IPCC), and United Nations Food and Agriculture Organization (FAO).

COMPONENTS OF BIOENERGY

The components of bioenergy are shown in Figure 1 [5] and explained as follows.

• Biofuels: This is a liquid energy fuel that can be produced from biomass conversion. It converts biomass into liquid fuels for transportation. Biofuel is fuel produced directly or indirectly from biomass such as fuelwood, charcoal, bioethanol, biodiesel, biogas (methane) or biohydrogen. Biofuels can replace conventional fuels like gasoline, diesel, and jet fuel. Many countries are exploring the possibility of replacing gasoline with biofuels.   A typical biofuel production is shown in Figure 2 [6]

• Biopower:  This is the generation of electricity from biomass sources.  It requires burning biomass directly, or converting it into a gaseous fuel or oil, to generate electricity

• Bioproducts: This involves converting biomass into chemicals for making products that typically are made from petroleum. Bioproducts and coproducts are produced in conjunction with biofuels, or that enable bioenergy production

• Biogas: This is gas composed principally of methane and carbon dioxide (CO2) produced by anaerobic digestion of biomass. It includes landfill gas, sewage sludge gas, and other biogas. Other biogas includes gas produced from the anaerobic fermentation of animal slurries and of waste in abattoirs, breweries, and other agrofood industries. Biogas is rapidly becoming a source of energy which contributes to the world’s electricity capability

• Biodiesel: Is produced through oil and methanol or ethanol in the presence of catalyst

• Bio-Ethanol: Is currently produced in large quantities by fermenting the sugar or starch portions of agricultural raw materials

Characteristics of Bioenergy

Bioenergy has some unique characteristics that distinguish it from the other renewable energy sources (RES). The diversity of applications for bioenergy is one of the most attractive characteristics of bioenergy. Bioenergy has the following unique features [7]:

• Environment friendliness: The acceptance of any new technology depends on its technical and economic advantages as well as its environmental and social acceptance. Bioenergy is superior to coal, oil, natural gas, and other fuels in terms of environment friendliness. Bioenergy is expected to contribute significantly to abating CO2 by substituting for fossil fuels. The use of modern bioenergy can reduce emissions

• Renewability: Bioenergy is renewable just like  wind, solar energy. The energy stored in biomass can be released to produce renewable electricity or heat. Biomass, such as wood and other solid bio-fuels, has been burned for cooking and heating and recently to generate electricity

• Transferability:  Bioenergy can be transferred into fuel ethanol and biodiesel

• Biomass: Can be stored and used on demand and contains a valuable form of energy, which can be converted into  electricity or heat

• Abundance in resources: Bioenergy is widely distributed ranging from North pole to South pole, almost every where. Biomass can be produced anywhere that plants or animals can live

Benefits and Challenges

One advantage of biomass fuel is that it is often a by-product of other processes, such as agriculture, animal husbandry, and forestry. Plants, animals waste, rotting garbage, human waste, garden waste, crop residues, wood residues, landfills, municipal and household waste, and their byproducts  are all sources of biomass [8].  Using bioenergy can decrease our carbon footprint and improve the environment.  Abundant and renewable bioenergy can contribute to a more secure, sustainable, and economically sound future.  It can supply domestic clean energy sources and reducing U.S. dependence on foreign oil. The use of forests and farms in producing bioenergy can help combat the harmful release of carbon dioxide. Unlike weather-dependent renewable technologies such as wind and solar, bioenergy is a very flexible energy source since it can be turned up and down quickly to meet demand. Bioenergy is also responsible for creating thousands of jobs especially in rural communities where they are most needed.  Bioenergy can also stimulate new investment in developing countries. Given these benefits, many national governments have introduced policies to promote bioenergy consumption.

Figure 1: Components of bioenergy [5]

Figure 2: A typical biofuel production [6]

However, bioenergy is a complex and sometimes controversial issue. The use of biomass can lead to a wide range of environmental and social impacts, both positive and negative. Major concerns remain about its effect on combating climate change and the environment; on agriculture, food security, and on people especially people in developing countries who will be affected by the changes in land use, land tenure [9]. Biomass needs to be produced as sustainably as possible.  Right now, bioenergy is not ready to replace fossil fuels because it is a complex and costly undertaking. It requires large plots of land and plenty of water. Some bioenergy technologies are not “mature”. Bioenergy development is often considered a risky business. Climate benefits of using biomass for energy have been questioned. Government policy is needed at a national and international levels to promote sustainable bioenergy systems.

Biomass energy or bioenergy is simply the energy from organic matter, which excludes fossil fuels. It is a renewable energy and a solution to the depleting fossil fuels.  Today, bioenergy accounts for roughly 9% of world total primary energy supply. Bioenergy can be considered as part of a larger transition to a bioeconomy in which bioproducts will be competing ultimately by means of efficiency and price.  The transition from a society that is heavily dependent on fossil fuels to one that embraces renewable is challenging.

The use of bioenergy all over the world is expected to increase significantly over the next decade. Bioenergy is widely regarded as the “fuel of the future.” It has been suggested that it is important to raise the awareness of bioenergy among young students as they are the future decision-makers. This may require updating curricula to accommodate topics like modern renewable energy technologies and their impacts on sustainability [10].  More information on bioenergy can be found in the books in [11-15].

1. "Biomass basics: The facts about bioenergy." U.S. Department of Energy, https://www.energy.gov/sites/prod/files/2015/12/f28/biomass_basics.pdf.

2. "Bioenergy basics." U.S. Department of Energy, https://www.energy.gov/eere/bioenergy/bioenergy-basics.

3. Kaygusuz, K. "Bioenergy as a clean and sustainable fuel." Energy Sources, Part A, vol. 31, no. 12, 2009, pp. 1069–1080.

4. Kuchler, M. and J. Hedrén. "Bioenergy as an empty signifier." Review of Radical Political Economics, vol. 48, no. 2, 2016, pp. 235–251.

5. Ke, L. and J.J. Chun. "Summary of the development of bioenergy in the future." International Conference on Materials for Renewable Energy & Environment, May 2011, pp. 400–403.

6. Den, J. "Bioenergy for electricity generation." University of Texas, Spring 2016.

7. Xilin, S. "Study on the feasibility of bioenergy development in China." Proceedings of the International Conference on Information Management, Innovation Management and Industrial Engineering, 2011, pp. 136–141.

8. "Bioenergy." Wikipedia: The Free Encyclopedia, https://en.wikipedia.org/wiki/Bioenergy.

9. Cushion, E. et al. "Bioenergy development: Issues and impacts for poverty and natural r esource management." World Bank, http://siteresources.worldbank.org /INTA RD/Resources/Bioenergy.pdf.

10. Halder, P. "Bioenergy education and training for the youth: Does it matter for the sustainability of bioenergy?" Proceedings of the International Conference and Utility Exhibition 2014 on Green Energy for Sustainable Development, Pattaya City, Thailand, Mar. 2014.

11. Kole, C. et al., editors. Handbook of Bioenergy Crop Plants. CRC Press, 2012.

12. Nelson, V.C. and K. L. Starcher. Introduction to Bioenergy. 2nd ed., CRC Press, 2015.

13. Khanal, S.K. Anaerobic Biotechnology for Bioenergy Production. Wiley-Blackwell, 2008.

14. Rai, M. and A. Ingle. Sustainable Bioenergy. Elsevier, 2019.

15. Konur, O. Bioenergy and Biofuels. CRC Press, 2017.