SAVANNAH GRASS BRIQUETTE, A REAL ALTERNATIVE TO WOOD ENERGY. CASE OF THE REALITIES OF THE IHOROMBE REGION IN MADAGASCAR

PHYSICAL SCIENCE AND ENVIRONMENT

Ihorombe, one of Madagascar's 22 regions, located in the southern part of the country. It is ranked among the poorest localities on the island, with 80.7 per cent of the population, slightly more than the proportion of poor people at the national level: 76.5 per cent. Moreover, it is an area with significant resources such as: the ecosystem, livestock, agriculture and special vegetation. For the ecosystem, it has a rich ecosystem, hosting a significant floristic and faunistic biodiversity, but it is subject to various pressures, all of them of anthropic origin, notably in the form of bush fires, wild fires, massive cutting for firewood and coal mining. It has 369,472 ha of natural forests, of which 49,959 ha are protected: the special reserve of Pic Ivohibe, the Kalambatritra nature reserve, part of the Andringitra National Park and part of the Midongy forest. The savannas of the plateaus occupy 2/3 of the whole area of the region and are mainly populated by grassy species: the andropogons (haidambo) and the Aristida (horona). In terms of domestic energy, the majority of households still have a traditional way of life: more than 7 out of 10 households still use collected firewood as the main fuel for cooking. Charcoal is used by 16.1% of households where precious woods such as varongy and rotra are used for coal mining. The results of various tests carried out at the laboratory of the energy department of the National Centre for Industrial and Technological Research (CNRIT) located in Fiadanana Antananarivo, showed that : firstly, cassava starch is the most interesting binder for agglomerating savannah grass; secondly, savannah grass has a biomass potential of around 10 to 15 t MS/ha/year; thirdly, savannah grass briquettes with 10% binder can compete with charcoal because they have respectively an average ICP of 5552.43 kcal/kg, a fuel consumption of 0.35 kg/h (0.36 kg/h for charcoal) less, a boiling time of 2.5 l of water 0.83 h (0.85 h for charcoal) faster and an efficiency of 29.84% higher than that of charcoal (23.74%). 60.5% of households, divided into three different socio-professional categories (well-off, medium, moderate) who participated in the acceptability test of savannah grass briquettes, are satisfied with the use of these savannah grass briquettes on its cooking capacity and convenience of use. The substitution of annual charcoal consumption at the level of an urban household in Ihosy district, Ihorombe region by the savannah grass briquette can preserve 0.1 ha of eucalyptus forest, i.e. 908.8 ha/year for the 9088 urban households in Ihorombe region and 611,562, 30 ha/year for all of Madagascar's 611,523 urban households, which greatly exceeds the forest area destroyed in 2017 according to Global Forest Watch of around 510,000 ha/year, i.e. the disappearance of 3.8% of Madagascar's forests.

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