Assessment of Crop Residues Energy Potential and Efficient Usage in the South-western Zone of Afghanistan

In the south-western zone of Afghanistan (Kandahar, Helmand, Urozgan and Zabul) about 807,890 tons of wheat, 945 tons of rice, 46,164 tons of barley and 105,276 tons of maize were produced in 2016-17. Based on the residues to product ratio (RPR) of the crops (1.8 for wheat straw, 1.5 rice stalks, 0.2 for rice husk, 1.3 for barely straw and 2 for maize stalks) about 1,454,202 tons of wheat straw, 1,418 tons of rice stalks, 189 tons of rice husk, 60,013 tons of barely straw and 210,552 tons of maize stalks were generated in the south-western zone of the country. By considering the lower heating values (LHV) of the crop residues (13.76 MJ/kg for wheat straw, 12.81 MJ/kg for rice stalks, 16.33 MJ/kg for rice husk, 13.97 MJ/kg for barely straw and 13.22 MJ/kg for maize stalks), it was resulted that 20,010 TJ energy can be generated from wheat straw, 18 TJ from rice stalks, 3 TJ from rice husk, 838 TJ from barely straw and 2,783 TJ from maize stalks. Cumulatively, around 23,653 TJ of energy can be generated from the selected crop residues in the south-western zone of Afghanistan in 2016-17. These crop residues are mainly used for cooking by using the very inefficient three stone cook stoves (η = 12.6%) and two support cook stoves (η = 13%). To use these crop residues more efficiently, it is advised to replace the mentioned inefficient cook stove with improved Chulha and Anagi II cook stoves, which have an efficiency of 21% and 22% and can save off to 43% and 40% fuel wood, respectively compared to the traditionally used cook stoves.