대한환경공학회지 (May 2021)
A Methodology to Estimate the Potential Production of Bioenergy Based on the Species, Cultivation Area Conditions, and Period of Forest Trees
Abstract
Introduction : Since the population increases and the industry develops, the demand for fossil fuels continues to increase, creating problems of energy resource depletions and accelerating global warming. Thus, many countries are making active efforts to replace fossil fuels with bioenergy as a renewable energy. In particular, trees managed and produced by forest industry have a high potential as energy sources for biofuel industry, because they have a conceptual characteristic of carbon neutrality. Recently, energy plan and policy are being developed to cultivate trees on fallow lands, environmentally restored sites, and ground-level work places of abandoned mines; however, economic feasibility for such plans and policies cannot be readily evaluated due to insufficient information on the amount of the energy to be produced from tree cultivation. Thus, the objective of this study is to develop a methodology which can be used to estimate the potential energy amount of the bioenergy from tree cultivation based on tree species, cultivation time, and cultivation area conditions. Methodology : The methodology consists of three stages. In the first stage, the total volume of the trees per area is estimated by using the number of trees per unit area and the average stem volume of the tree, which are affected by the site index representing the environmental conditions of cultivation area. In the second stage, the total mass of biomass is calculated by using the density of wood, the biomass expansion factors for the above-ground biomass, and root-shoot ratio. In the last stage, the amount of the energy produced from the tree cultivation is estimated by taking into account the caloric value evaluated based on the carbon, hydrogen, and oxygen compositions of the tree. Case Study : A case study for conifers and broad-leaved trees is performed to demonstrate the methodology. The conifers are Jungbu local pine, Korean white pine, and Japanese larch, and the broad-leaved trees are oak, red oak, and birch. The results of the case study validate the developed methodology and clearly showed the procedure and necessity for the methodology by estimating the bioenergy productions from the trees. Conclusions : The developed methodology can be used to provide practical information needed to determine the economic feasibility of the plan, policy, and project for tree cultivations.
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