Other Environmental Impacts

Apart from life-cycle GHG emissions, Table 2.3 shows the other three environ­mental impact potentials including acidification potential (AP) which is expressed as g SO2 eq., eutrophication potential (EP) which is measured in g PO3 eq., and photochemical ozone creation potential (POCP) is measured relative to ethylene as expressed in g C2H4 eq. which is determined based on the impact potential factors of CML method (Heijungs et al. 1992). As per MJ of fuels, palm biodiesel has lower AP but higher EP as compared to diesel. However, there is no significant difference of POCP between them. In addition, the assessment also shows that utilization of EFB and POME in all scenarios (i. e. scenario 1-3) could help

Table 2.3 Potential environmental impacts of palm biodiesel compared to diesel (per MJ of fuels)

Environmental impacts

Environmental impact potentialsa

Palm biodiesel

Dieselb

% net avoided impact potentials compared to diesel

Acidification (g SO2 eq.)

*0.40-0.41

* 0.44

* 7-9 %

Photochemical oxidation

*0.03

* 0.03

(g C2H4 eq.)

Eutrophication (g PO4-eq.)

*0.11

* 0.09

*(-11)-(-12%)

a Environmental impacts entire the life-cycle production and use of fuels b Environmental impacts of diesel production are evaluated based on LCI data of Ecoinvent database (2007) and tailpipe emissions of diesel in LDDV (Pleanjai 2008)

improve the environmental performance of palm biodiesel in all impact categories (Silalertruksa and Gheewala 2012).

For example, oil palm plantation is the main contributor to AP and this origi­nates from the SO2 and NOx generated during production of N-P-K fertilizers. Therefore, substitution of chemical fertilizers used at the plantation by the compost from the co-composting of EFB and POME would be an opportunity to mitigate the environmental burdens of palm biodiesel (Stichnothe and Schuchardt 2010). POME is found to be the major source of eutrophication impact followed by fertilizers used in the oil palm plantation stage and methanol in the biodiesel conversion stage, respectively. Therefore, apart from good management of POME at the palm oil mills, the effective use of fertilizers in agriculture could be one of the measures in practice to reduce this impact. Additionally, the proper manage­ment of POME would also help reduce POCP as this impact associated with the emissions of NOx, CH4, and CO; methane emissions from open ponds at the oil mills are the major contributor in high POCP of palm biodiesel.

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