Bioenergy

Technology

Many processes are available for producing bioenergy.  These range from conventional uses of biomass such as burning of sticks and branches to generate energy for cooking and heating, to modern production processes like converting sugar and starch crops to ethanol, to even more advanced technologies such as gasification of wood chips for transport fuel production. How a fuel is produced from biomass materials can depend on a variety of factors, including the feedstock that is been used, the associated biomass conversion technology that is applied, and the energy carrier that is desired. 

Feedstock
AFP/PORNCHAI KITTIWONGSAKULThe development of bioenergy is closely linked to the type of biomass resource or feedstock that can be used as or converted to energy.  Each feedstock has its own advantages and disadvantages in terms of content of usable energy material, areas where these can be grown,  level of energy inputs that are required, natural resources use intensity i.e. land and water-use, competition with food. Sources of biomass for bioenergy production include agricultural conventional crops like sugar cane, sugar beet, maize, cassava, wheat; oil crops like soybean, rapeseed, jatropha; and lignocellulosic materials from herbaceous, short rotation wood crops and both agricultural residues and wood.

Processing
Converting biomass into fuels and power is carried out via biochemical and thermo-chemical processes. The various technologies options may be compared in terms of energy efficiency, feedstock requirements, installation costs, carbon emissions, labour intensiveness or any range of costs and benefits. Production chains need to explore the potential for beneficial use of by-products in local markets.

First Generation versus Second Generation Technologies
FAO/A.ContiBiomass processing technologies are widely grouped into first generation and second generation. First generation technologies are well established, these include transesterification of plant oils, fermentation of plant sugars and starch for liquid biofuel production, anaerobic fermentation of organic residues to generate biogas, combustion of organic materials for heat recovery or combined heat and power (CHP) systems for the production of both heat and electrical power.  Second generation or advanced technologies often refer to the conversion of lignocellulosic materials to fuels. These technologies comprise a range of alternatives such as enzematic production of lignocellulosic ethanol, syngas gas based fuels, pyrolysis-oil based biofuels, gasification and others but are not yet economically viable and technical aspects are still under development. 

Research & Development in Bioenergy Crops and Conversion Technology
Much attention is currently focused to the production of liquid biofuels that are manufactured with first generation technologies because they rely on feedstocks derived from food-crops, the so called first generation biofuel. Thus, this has heighten the needs to identify and work on agronomic potential of alternative bioenergy crops including non-edible oil crops such as jatropha, castorbean, jojoba, karanja that can be grown in land unsuitable for food crops and multipurpose crops like sweet sorghum that can yield food in the form of grain, fuel in the form of ethanol from its stem juice, and fodder from its leaves and bagasse.

Deployment of second generation technologies offers an opportunity to expand the type of feedstock and to take advantage of currently unused lignocellulosic sources.  It also facilitates the use of energy crops that can be grown in land unsuitable for food crops. These technologies offer a more efficient production and making use of the entire plant beyond the carbohydrate component. Further research and development on bioenergy conversion technologies is required to overcome the technical barriers for them to become a viable option.

Biotechnology applied to bioenergy production
Many biotechnology tools are currently being applied for different purposes in agriculture (e.g. genetic improvement of plant varieties and animal populations or characterization and conservation of genetic resources) and can also be applied for bioenergy production as well.

FAO/G. Blaak

Some of these applications include fermentation, marker-assisted selection, genomics and genetic modification, involving application to crops, grasses, forest trees and micro-organisms (bacteria, yeasts, microalgae). They include applications to bioenergy production systems that are currently a reality (first-generation biofuels and biogas) as well as to those that are still at the experimental stage (second-generation biofuels and microalgal biodiesel).

Biotechnology applied to bioenergy production can increase the efficiency of both parts of the production cycle: the production of biomass for bioenergy and the subsequent conversion of the biomass into biofuels.

FAO's Work

Information on bioenergy crops and their environmental requirements are available in a FAO developed knowledge management tool known as Eco Crop. This decision support tool includes over 2500 species of which 451 are used as fuelwood feedstocks and 44 are classified as fuels/petroleum substitutes. A mapping function for the database is currently being put in place to enable easy access to geographic maps indicating where crops will be highly adapted.

Knowledge on the genetic resources of under-utilized bioenergy crops will also be available through a knowledge platform database linked to EcoCrop and the Global Partnership Initiative for Plant Breeding Capacity-Building (GIPB). This tool will allow stakeholders to identify and share elite planting and breeding materials needed for domestication of new bioenergy crops.

The FAO, the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and IFAD recently held a technical consultation in Rome focusing on three bioenergy crops proposed for cultivation by smallholder producers: sweet sorghum, tropical sugar beet and jatropha. The proceedings of the meeting will be published by FAO jointly with the other co-hosts. Future technical consultations for cassava and for cold-tolerant oil palm are also scheduled to take place in 2009.

In addition, on 12 October 2007, an FAO Seminar was held in Rome on "The role of agricultural biotechnologies for production of bioenergy in developing countries". The Seminar focused on the opportunities and challenges offered by biotechnologies to overcome the conflict between bioenergy and food production, including between different land uses, by developing a second generation of biofuels based on the biotechnological transformation of lignocellulosic biomass. It covered genomics and post-genomics, genetic modification, fermentation technologies, enzymology and other allied technologies involving living organisms.

The FAO Working Group on Biotechnology and the FAO Working Group on Bioenergy organized a moderated e-mail conference (10 November - 14 December 2008) on "The role of agricultural biotechnologies for production of bioenergy in developing countries". Sixty percent of the posted messages were by participants living in developing countries. A background document was prepared before the conference. All messages from the conference can be viewed here.