The fruits of J. curcas are about 2.5 cm long and are ovoid in shape. Average fruit yields are about 3.5 tons ha-1, and, yields of 1-1.25 tons ha-1 are common when grown in wastelands under rain-fed conditions (Kumar et al. 2003). The fruit is made up of the shell and seeds. Two to three seeds are present in each fruit. It has nearly 400-425 fruits per kg and 1,500-1,600 seeds per kg weight (Singh et al.

2008) . In dry J. curcas fruit, shell accounts for 35-40 % and seed for 60-65 % of weight (Vyas and Singh 2007). All these components of the J. curcas fruit have been used as sources of bioenergy.

17.4.1 The Shell

The shell is removed mechanically during oil extraction from the fruit. One hectare of land under Jatropha plantation produces about one ton of shell material which can be used as energy source. The shell contains 34 % cellulose, 12 % lignin, and 10 % hemicelluloses. The shells have 16 % fixed carbon content, 15 % Ash, and 69 % volatile matter respectively (Singh et al. 2008). The J. curcas shell has caloric value of 16.9 MJ kg-1 (Vyas and Singh 2007) to 17.2 MJ kg-1 (Openshaw 2000) implying one hectare plantations can supply energy of 16.9-17.2 GJ vice shells alone. J. curcas shells owing to their chemical composition are also a good feed­stock for briquetting, bio-methanation and pyrolysis (Singh et al. 2008; Manurung et al. 2009; Sotolongo et al. 2009).