Bioenergy and Biofuels
Biomass is an increasingly important renewable energy source that has the potential to reduce dependence on hydrocarbon-based energy sources. This module presents an overview of the use of biomass to produce bioenergy with emphasis on bioethanol, and an explanation of the main steps in producing ethanol from wood.
After viewing the module presentations and laboratory videos, users should be able to:
- Explain how bioenergy and biofuels are renewable options, if grown and produced sustainably, and that bioenergy and biofuels can displace a substantial amount of conventional energy sources such as oil, gas and coal.
- Describe the importance of biomass as a renewable resource for both energy production generally, and transportation fuels specifically.
- Identify several conversion technologies (that use various sources of biomass) and their different advantages and disadvantages (biochemically and thermochemically produced options are compared). Explain that technologies have reached different commercialization or “technical maturity” levels (first and second generation biofuels).
- Explain why by-products improve the economic viability of production (the biorefinery concept).
- Identify ethanol as one of the transportation biofuel options and explain why.
- Describe the three major steps in ethanol production from wood biomass (pretreatment, hydrolysis and fermentation) and identify key procedures and research questions for each step.
Listen to each Presenter respond to the question: How did I get interested in this area of study? by clicking on their photos.
For more information about the Presenters, click on their names:
Process 1: Pretreatment of Wood
Dr. Richard Chandra talks about the first step in the conversion of wood to biofuels. Pretreatment is a physical and/or chemical process that breaks down the biomass so that it is more accessible to the enzymes which carry out hydrolysis. The objective is to put enough energy into the pretreatment process so as to effectively separate the key components of the wood: cellulose, hemicellulose and lignin, without their destruction. The challenge is to find a pretreatment process that produces the maximum recovery, enables easy hydrolysis, is useable with diverse biomass and is relatively inexpensive.
Process 2: Hydrolysis of Cellulose to Simple Sugars
In his lecture, “enzymatic hydrolysis of lignocellulostic biomass”, Dr. Valdeir Arantes explains how pretreated wood (“mush”) is converted to simple, monomeric fermentable sugars such as glucose. Enzymes, isolated from the same fungi that work to breakdown trees in nature, are used as catalysts to speed up this hydrolysis (breakdown) of cellulose. Tricoderma reesei, for example, is an important fungi from which such enzymes are extracted.
Laboratory 1: Wood to Mush
This lab video takes place in the Process Development Unit. As wood is meant to stay together, large amounts of energy are required to break it apart. First the wood is chipped so as to increase the surface area and then it is added to the steam gun. The boiler supplies high pressure steam (~200°C) and the process takes from 2 to 10 minutes. Both solid (cellulose- & lignin-rich) and liquid (hemicellulose-rich) products accumulate in the collection vessel.
- BC Bioenergy Network
- UBC Forest Products Biotech.& Bioenergy homepage
- International Energy Agency — Bioenergy
- International Energy Agency — Bioenergy, Task 39
- U.S. Dept. of Energy, Biomass Program – Information Resources
- U.S. Energy Information Administration
Potential Questions for use by Instructors
- One could argue that making biofuels from cellulosic biomass is not economically viable. Why is it still an important area to research?
- List the 3 main steps in producing ethanol from wood. Explain the basic concepts associated with and output of each step. What is (are) the key researach question(s) in each step?