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environment should be utilized. For advanced biofuels, torrefaction, which increases density more than pelleting in some cases, is an efficient storage system.

Defining what a good practice is for conversion technolo-gies can be difficult, since it is highly dependent on the objectives of the bioenergy project. For example, use of coal power for conversion of biomass to liquid is a bad practice if improved GHG balance is an objective, but can be a good practice if only energy security and financial competitiveness are considered. For conversion practices, applying the principles of high resource and conversion efficiencies can be regarded as general good practice - utilise as much of the feedstock for useful energy and recover the waste whenever viable.

Integrated Food Energy Systems

The concept of Integrated Food Energy Systems (IFES) (Sachs & Silk, 1990) is a farming system model designed to integrate, intensify and thus increase the simultaneous production of food energy either by physical coexistence (i.e. combining food and fuel feedstock on the same land, through intercropping of agroforestry systems), and closed

loop systems (i.e. transforming the by-products of one system into the feedstocks for the other).

Closed loop agricultural systems maximize synergies between food crops, livestock, fish production and sources of renewable energy (see Case Study). They are characterized by some operational principles:

High productivity in cultivation

Optimal use of biomass (based on the idea that nothing is ‘waste’)

Closing the loop: waste treatment by anaerobic digestion

Often crop and livestock integration

In Vietnam, not unlike many other developing countries, traditional fuels such as wood and coal for cooking, are becoming increasingly scarce and expen-sive, and can contribute to deforestation. Increasing livestock production in rural communities with high population density leads to health and environmental issues from the quantity of animal dung being produced. Realizing this Vietnam has embarked on an integrated land management scheme, supported by the Vietnamese Gardener’s Association (VACVINA) called the VAC integrated system. It combines garden-ing, fish rearing and animal husbandry to make optimal use of the land.

Biogas digesters are part of the solution offered by this initiative, using the wastes to generate energy, and the resultant slurry as a fertilizer to improve soil quality. A market-based approach has been adopted to

disseminate the plants. The service provided to those buying the digester is comprehensive. The customer must have at least four to six pigs or two to three cattle that provide all the inputs (animal dung). Households use the biogas as fuel and slurry as fertilizer. They pay the total installation cost for the digesters to local service providers, and operate the biodigester using instructions provided by local service providers.

A biodigester produces enough daily fuel for cooking and lighting. It improves the surrounding environment, whilst livestock produce meat, milk and fish products for local consumption and subsistence farming. Vegetable production is enhanced through use of biogas slurry, and latrines can be added to the system to enable human waste to be used for energy.

Practical Action, 2009

Case study: Vietnam Biogas Farms

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