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Many people in the energy field refer to agricultural residues as an "unused resource" and point to residues as being a potential solution to many countries' energy problems. While agricultural residues can offer a useful additional source of energy, it is dangerous to make assumptions without examining the role that these residues play within the relevant farming and socio-economic systems.

One of the biggest mistakes that can be made is that of aggregation. A number of studies have identified large amounts of residue at the national level and projects have been designed accordingly. Once on the ground, however, it often turns out that the residues are highly decentralised and the cost of collection cannot tee economically justified.

The availability of residues for fuel use is difficult to measure at the national level. It only becomes slightly clearer when good-quality village studies are available. For example: modern high-input systems with several crops per year can give far more residues than traditional rain-fed systems. On the other hand, many HYV (high yield variety) crops grow on much smaller stalks than traditional varieties. High-input farming, relying on chemical fertilizers, will tend to regard residues as a waste whereas traditional farming methods may use much more of the residues as mulch, compost or fodder. In certain regions, farmers pay pastoralists to graze their cattle on their land to process their residues into high quality manure.

Residue production alone is not enough. The question of access to those residues is equally important. In India, people will weed wealthier landowners' land, simply to obtain fodder for their cattle: they receive no payment. While a prosperous farmer, with several hectares of farmland and a sizeable herd of cattle, may produce a large suplus of residues, a landless labourer may have automatic access to very little. What his family is able to obtain in practice may be determined more by the generosity of his employer than by the level of production in the village.

The other major danger in identifying unused resources is actually in recognising how unused the resource really is. Agricultural residues provide three major - often conflicting - inputs to farming and social systems: fodder for livestock, compost/manure for soil fertility and energy for cooking and crop processing. Residues also provide roofing material, raw materials for a range of handicrafts and, as ash, additions to ceramics, soap and other products.

The conflicts can sometimes be overplayed. It is often considered, for example, that any dung burnt is to the immediate detriment of soil fertility and stability. While this is in theory true, there is a variety of practical and economic considerations which prevent farmers from doing what in strict soil science terms would be best. Organic farming is much more labour-intensive than using concentrated chemical fertilisers. Animal dung can be quite difficult and time consuming to collect unless the animals are penned in. Some crop residues decompose so slowly as to be of little nutritional or structural benefit to the soil. Again, farming systems have to be examined on a local basis: only if residues are currently being used for fodder or fertiliser can one measure a conflict with energy use.

A more important conflict can be between different users of the same residues. Many briquetting projects fail to recognise the problem. Briquetting is en excellent way of upgrading many residues, but it also raises their price. Residues that were a waste to a farmer become something of value. That is fine for the farmer, but what about the poor landless labourer who is currently using that residue to cook with? However inferior that material is as a fuel, it is all he can afford. Briquetting in these circumstances is actually depriving the poorest people of one of their very few sources of energy.

It is clearly essential that any briquetting project should be preceded by a survey of the sources of raw materials both locally and regionally, taking account of all the factors described. This should include seasonal variations and costs and possible changes in the energy situation for several years ahead.

Last edited by Miriam Hansen .
Page last modified on Wednesday October 6, 2010 10:54:02 GMT.
  • A practitioner's journal on household energy, stoves and poverty reduction.



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