Rice husk-based electricity

CASE STUDY OF RICE HUSK-BASED ELECTRICITY AND COAL-FIRED ELECTRICITY... 

The result of PROSUITE calculation shows that there is no difference between impacts of coal-fired electricity and rice husk-based electricity on social well-being at an economy-wide scale, while there is a small difference at a functional unit scale. This can be explained by the small contribution of the product system on the whole economy and society. Moreover, it is surprising that both product systems do not contribute to the social inequity at regional as well as global levels. Details of social well-being impacts can be found in Table 14.7. 

Being similar to the impact on social well-being, the result of PROSUITE shows that there is no difference between coal-fired electricity and rice husk-based electricity because of the small share of the products system to the economy. In other words, replacing coal-based electricity with rice husk-based electricity does not bring any positive change (in terms of prosperity) to the economy. Details of prosperity impacts are presented in Table 14.7. 

The rice husk-based bioelectricity hfe cycle starts with the production of agricultural inputs such as rice seed, fertihzer, and pesticide, which then are used for rice farming. After the rough rice grains are harvested, rice husk is separated from brown rice [44]. While the brown rice is normally processed to obtain white rice for commercial purpose, the rice husk is directly transported to the power plant for generating electricity. The operation of rice husk-based power plants is similar to that of coal-based power plants. Nevertheless, as rice husk tends to contain less sulfur than coal, limestone consumption is omitted when considering the rice residue-based power plant. 

There are two product systems compared here the reference system (coal-fired electricity) and the prospective system (rice husk-based bioelectricity). 

The two product systems have the same function of providing electricity, but slightly different functional units, which are 1 MWh of coal-fired electricity and 1 MWh of rice husk-based bioelectricity. 

The weighted sum results are calculated on the principle that the positive impacts can compensate for the negative impacts. In other words, impact on social well-being and impact on prosperity can be subtracted from the impacts on human health, ecosystem quality, and natural resource. As a result, the higher the scores are, the worse the product systems are. The weighted sum result of rice husk-based bioelectricity impacts on sustainable development is half as much negative as that of coal-fired electricity, at 13.82 and 28.02, respectively. 

The environmental, economic, and social impacts are allocated for main products and coproducts (e.g., rice and rice husk in the rice husk preparation process, electricity and ash in the electricity generation process) according to their economic values. It should be noted that in this case study the main product (electricity) is quantified in MWh while its coproducts (bottom ash, fly ash, etc.) are quantified in tonne. The differences in quantification units make it impossible to allocate environmental, social, and economic impacts by weight basis. Among the available allocation methods, though the economic-based allocation is Hmited because of changing market values, it is, in this case study, the most suitable choice for assessing the sustainability of the product system. 

Suwanprateeb and Hatthapanit [6] compared the use of black rice husk ash based silica as a filler in epoxy resins used for embedding electrical and electronic devices to the use of two commercial fillers, fused silica and crystalline silica, at different weight fractions between 20-60%. Increased mixing viscosity, thermal expansion... 

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