Considering factors such as the local climate and soils, a number of species have been identified as appropriate for available lands in Sri Lanka. These species offer a high degree of certainty to produce firewood for biomass-based thermal power plants (see Table 10.2).

Except the Eucalyptus species mentioned in Table 10.2, all others are legumes that enrich soils by fixing atmospheric nitrogen. This also indicates their ability to grow in poor sites, and lower the requirements for fertilizers. Therefore, these species are very much suited for degraded sites found in the dry and intermediate zones in Sri Lanka (Evans, 1992; Ariyadasa, 1996; FAO, 1993, 1997).

Biomass production from different species are shown in Table 10.3. Although commercial-scale short-rotation energy plantations are rare in Sri Lanka, the growth parameters of the existing fuelwood plantations could be used to determine the potential biomass yields of the recommended species in future short-rotation planta­tions. The yield-estimates given in Table 10.3 are based on actual field data collected from different plantations situated in different parts of the country.

Biomass production of Eucalyptus robusta is similar to that of Eucalyptus grandis while Acacia mangium is similar to Acacia auruculiformis (Perlack et al.). Leucaena leucocephalla would produce about 8-10 dry tons/ha under Sri Lankan conditions. The average yield during different harvesting periods in a newly established energy plantation in Sri Lanka are given in Table 10.4 (Gunaratne and Heenkenda, 1993).

This gives an annual average yield of 10 dry tons per hectare, with a total of about

7.5 MWh of annual energy per hectare at an overall plant efficiency of 18 per cent, and a З-year rotation of the fuelwood plantation.