Bioenergy is derived from plant- or animal-based organic matter called “biomass”. Biomass sources include:
- animal wastes
- agricultural feed crops, waste and residues
- aquatic plants
- landfill gases
- municipal wastes
- trees, wood waste and residues
- other organic waste materials.
Biomass is used to produce a variety of energy-related products including electricity; liquid, solid and gaseous fuels; heat and chemicals.
For example, methane gas from landfills and other wastes, such as manure, can be used to generate electricity and heat. Wood waste can be made into pellets for heating or power production. Crops such as sugar, corn or wheat, and soon cellulosic materials such as hay, straw and wood wastes, can be used to make ethanol, a substitute for gasoline; canola crops and oil wastes can be used to make biodiesel.
Due to a rapid increase in the use of bioenergy, in particular liquid biofuels such as ethanol and biodiesel, serious questions have been raised regarding current bioenergy practices. Undesirable impacts of bioenergy include impacts on world hunger from higher food prices; and harm to the land, water, forests and small farmers in developing countries from expanded and more intense agricultural operations.
To be truly sustainable, the use of bioenergy cannot lead to overall degradation of the natural environment or undermine people's abilities to meet their needs. Several Canadian and international criteria have been developed to assess the sustainability and impact of biomass resources. These include the Roundtable on Sustainable Biofuels, Environmental Choice, the Eugene Standard, the Sustainability Criteria for Bioenergy (being developed with the support of the UN Foundation Biofuels Initiative and the German NGO Forum on Environment and Development, and the Criteria for Sustainable Biomass Production under consideration by the Government of the Netherlands.
In general, bioenergy from dedicated land is less sustainable than bioenergy from wastes or residues. Using dedicated land means that land cannot as easily be used for other purposes (eg. agriculture, forestry, carbon sequestration, wetlands, natural areas). This can reduce supplies in other areas, and result in either shortages or create a demand for other land to meet these needs leading to higher prices for food or forest products, compromised ecosystems, deforestation, more fertilizer and pesticide intensive agriculture and increases in greenhouse gas emissions.
Bioenergy from wastes or residues, on the other hand, typically uses a resource that is not otherwise used for another purpose and converts it to energy. This avoids many of the indirect impacts of using feedstocks from dedicated land. However, it is important to note that forestry or agriculture wastes or residues need to be harvested without significant negative impacts on the area they are taken from. For example, a certain height of stubble needs to remain on fields where straw is removed.
Examples of Capturing and Using Biomass Resources
Anaerobic Digestors (Biogas Plants)
Organic material such as plant matter or manure can be broken down by bacteria to produce biogas, which takes place in an oxygen-free environment inside a digestor tank. Biogas has a high concentration of methane and can be used much like natural gas to produce electricity or heat. Other products of the anaerobic digester include treated water and nutrient-rich solids that can be used as a fertilizer or a land amendment.
Small biogas plants are used by farmers in many developing countries to provide household gas and fertilizer from cattle manure. Larger anaerobic digestors are more common in Europe but are starting to show up in Canada. Many of these digestion plants use manure from cattle feedlots or swine operations such as the biogas plant in Vegreville, Alberta that uses the biogas to produce electricity. Another biogas plant is the Dufferin waste disposal facility in Toronto, which receives organic matter from the landfill. Several other biogas plants are in the planning stages.
Biogas plants provide an excellent method for disposing of waste while, at the same time, extracting energy and providing a valuable fertilizer product.
Anaerobic decomposition of waste also occurs in landfill, and plants are being built in to recover and use this biogas for electricity production.
Biofuels: Ethanol and Biodiesel
Ethanol is an alcohol that can be used as a substitute fuel in gasoline powered vehicles. It is typically sold as a 5-10% blend with gasoline and will work in any vehicle without modification. High fraction blends such as 85% ethanol in gasoline (E85) can be used in many modern gasoline-powered vehicles, or in older vehicles with minor engine modifications.
Ethanol is produced from biomass sources such as sugarcane, corn and wheat that contain natural sugars or starches. Starches are converted to sugars that are then fermented to produce the ethanol in much the same way distillers produce alcoholic beverages.
Newer technologies are being developed to produce ethanol from organic waste such as straw, corn stover, wood and even municipal trimmings. These organic wastes are known as lignocellulose products. To convert these wastes into ethanol, their plant fiber matrix must be broken down using water, pressure and heat, or acid. Once the plant fiber material has been broken, sugars can be extracted for fermentation into ethanol.
Today there are nine ethanol facilities either in operation or under construction in Canada and more than 120 plants in the United States. In eastern Canada and the U.S., corn is used as the feedstock while in western Canada wheat is used. Brazil produces a large amount of ethanol from sugarcane, and many vehicles in the country have been built to run directly on ethanol fuel. In Europe, ethanol is produced in Sweden, Denmark, Germany, the United Kingdom, France, Italy and Spain. Many Asian countries such as Japan, China, India, and Indonesia are also developing ethanol production capacity.
Biodiesel is a diesel fuel substitute that can be produced from agricultural oils, recycled vegetable oils or animal fats. Both fuels can be used in conventional engines in low-percentage blends without modification, and can reduce overall emissions of criteria air contaminants (CACs) and greenhouse gases.
Biodiesel and ethanol fuels are not all created equal. The different feedstocks and technologies used can have a wide range of environmental impacts. To get the maximum environmental benefits, it is important that petroleum fuels are not simply replaced by renewable fuels; rather, the fuels with the lowest life-cycle GHG and CAC emissions should be produced and used. For example, cellulose ethanol and biodiesel have lower overall GHG emissions than starch ethanol. As well, the environmental impacts of renewable fuels vary depending on the agriculture and forestry practices used to produce the feedstocks, and the way in which co-products of the fuel production process are used. Government policies should provide targeted support to fuels with the lowest life-cycle environmental impacts.
Benefits
- Bioenergy can provide higher incomes to the agriculture and forestry industries, although this may be tempered by higher costs of land, machinery and other inputs such as fertilizers and pesticides.
- There is a likely reduction in greenhouse gas emissions when compared with conventional fuels over their entire life-cycle. This reduction can turn into increased emissions, however, if the bioenergy use results in a change to the way land is being used. For example, clearing forests to plant an agricultural crop releases a very high amount of greenhouse gas emissions that negate any climate benefit from the new crop itself.
- Some bioenergy sources can improve air quality by either improving the way the biomass was previously disposed, or by burning cleaner than conventional fuels. For example, burning wood waste in a powerplant with high quality pollution prevention technologies is much cleaner than older methods of disposing of the waste such as beehive burners. Biodiesel is also known to result in much lower air pollution than conventional diesel.
Challenges
- Bioenergy that comes from dedicated crops have several potential risks. These include possible impact on food prices and availability, and land and water impacts of conventional agriculture. Bioenergy from dedicated land may also directly or indirectly result in land being cleared for new crop growth - a practice that can lead to deforestation, erosion and a very high release of greenhouse gas emissions.
- Collecting and processing biomass resources in sufficient quantities can be a challenge. The energy needed to grow, cut and transport crops to a bioenergy plant and then process these materials into fuels or power is not insignificant. Waste or residue biomass resources have the lowest energy requirements, while agricultural crops usually have the highest.
Global Status and Potential
In 2003, the European Union has adopted two biofuel directives. These directives set targets for the share of renewable fuels in the transport fuel market (2% by the end of 2005 and 5.75% by the end of 2010). The 2005 target was not achieved but the industry is growing rapidly and it expected that the 2010 target will be achieved.
The EU has also adopted a Biomass Action Plan that sets out measures to increase the development of biomass energy from wood, wastes and agricultural crops by creating market-based incentives for its use and removing barriers to the development of the market. Implementation of the plan will help the EU to cut its dependence on fossil fuels, reduce greenhouse gas emissions and stimulate economic activity in rural areas.
Bioenergy ranks second (to hydropower) in renewable U.S. primary energy production and accounts for 3% of the U.S. primary energy production.
Brazil is the world's largest producer of biofuels. Production is expected to rise from 15.4 billion litres in 2004 to 26.0 billion litres by 2010. Ethanol from sugarcane provides 50% of automobile fuel in Brazil.
Canadian status and potential
While both ethanol and biodiesel have considerable presence in international markets, Canada is a relative newcomer in production of these fuels. A key difference between Canada and countries with greater market presence is the level of supportive government policy. In the U.S. and Europe, state and federal governments offer a wide range of support that has resulted in billions of litres of increased annual production.
In Canada, approximately half of the provinces have announced renewable fuel mandates or exempted biofuels from the provincial fuel tax. Ontario provides Standard Offer Contracts to small biomass producers (as well as hydro and wind electricity producers). In 2006, the Alberta government announced a biogas production incentive that will be available to producers between 2007 and 2011.
The key federal government support for the industry has been a credit for the federal fuel tax. The Government of Canada recently announced that a 5% national renewable fuel standard will be in place by 2010. To meet this target, it is projected that Canada would need to produce 3.1 billion litres of renewable fuel - a volume that far exceeds the capacity of current and proposed domestic production facilities and could represent a twelve-fold increase in biofuel production.
Links for more information
Organizations
- BIOCAP Canada Foundation
- Canadian Renewable Fuels Association (CFRA)
- Canadian Bioenergy Association (CANBIO)
- UN Foundation — Biofuels Initiative
General Information
- Bioenergy Wiki
- EU Biofuels Action Plan
- EurObserv'ER biofuels Barometer 2006: A primer on the status of green fuels [biofuels] in the EU
- Pollution Probe's Primer on the Technologies of Renewable Energy
- U.S. Renewable Fuels Standards
Anaerobic Digestors
- City of Toronto — Dufferin Organics Processing Facility
- Clear-Green Environmental Inc.
- ECB Enviro North America Integrated Waste Management System (IWMS)
- Government of Ontario — Anaerobic Digestion Basics
- Government of Alberta — Anaerobic Digestion
- Highmark Renewables
