Abstract
We conducted a study aimed at calculating the energy balance and CO2 emissions of various scenarios for rice straw recycling, employing the concept of Life Cycle Assessment. The actual energy gain per mass of rice straw harvested in one ha of paddy field was the greatest in the Fuel Gas Production Scenario (45.5GJ), followed by Methanol Production Scenario (15.4GJ) and then the Electricity Generation Scenario (4.5GJ). The energy balance per ha, including nutrient input, was as follows: production of 40.2GJ for Fuel Gas Production and 10.1GJ for Methanol Production, and consumption of 0.8GJ for Electricity G eneration, 6.1GJ for C omposting-Nutrient R estoration and 5.3GJ for D isposal/Incineration. T he E lectricity Generation Scenario produced the largest CO2 emission and the Fuel Gas Production Scenario produced the least emission. The CO2 emission, which was the sum of emissions in each Scenario and the consumption of energy equivalent to the calorific value produced in the energy production Scenario, was estimated with the following results: the emission in the Methanol Production Scenario was the lowest (11, 614 kg of CO2/ha) and that in all energy production Scenarios would be smaller than that in the Composting Nutrient Restoration and Disposal/Incineration. It is considered that these outcomes indicate the necessity of multi-dimensional approaches for the evaluation of energy production from biomass and biomass recycling in rural development planning.
