LCA手法による発電プラントの評価 -CO_2ペイバックタイムの算出- Estimation of Power Plants by LCA
代替エネルギーとして海洋温度差発電と太陽光発電, また既存の発電方式として石炭, 石油, LNG火力発電および水力発電に着目し, 各発電方式の発電所の建設について, ライフサイクルアセスメントの手法を用いてCO<SUB>2</SUB>排出量を算出した.また運用エネルギーをも考慮し, 火力発電に対する自然エネルギーのCO<SUB>2</SUB>ペイバックタイムを算出しそれぞれの発電方式を評価検討した.LCAの手法を用いて, 各発電技術の建設時や運用時のCO<SUB>2</SUB>排出量を算出し, 自然エネルギーによる発電方式の, 火力発電方式に対するCO<SUB>2</SUB>ペイバックタイムの算出を行った.これらにより, LCAの手法を用いて, 自然エネルギー, 特に海洋温度差発電, 水力発電の有用性が定量的に明らかになった.<BR>また, 各素材のCO<SUB>2</SUB>排出原単位の違い, つまりLCIの違いがその計算結果に大きく影響することがわかった.
CO<SUB>2</SUB> payback times were calculated for renewable energy electric power plants (hydroelectric, OTEC (Ocean Thermal Electric Conversion) and PV (photovoltaic)) by LCA (Life Cycle Assessment), using fossil fuel-fired electric power plants (coal, oil and LNG) as a reference.<BR>The CO<SUB>2</SUB> emissions resulting from plant construction and production of plant construction materials were calculated for each case. The amounts of materials for construction of each power plant were taken from previous papers. The resulting LCI (Life Cycle Inventory) was calculated by "NIRE-LCA", LCA software using a bottom-up approach developed at the National Institute for Resources and Environment.<BR>The calculated total CO<SUB>2</SUB> emission from the construction of each power plant was divided by annual net generated electricity. Subsequently, CO<SUB>2</SUB> payback times were calculated from estimates of CO<SUB>2</SUB> emissions from construction and operation of renewable energy power plants with fossil fuel-fired power plants used as the reference. CO<SUB>2</SUB>payback times for hydroelectric and OTEC (100 MW) power plants were very short in comparison to PV power plants, which was mainly due to CO<SUB>2</SUB> emissions construction. It was also suggested that CO<SUB>2</SUB> payback times for all renewable energy electric power plants evaluated by the present paper were much shorter than typical operational lifetimes of renewable energy electric power plants.
化学工学論文集 23(1), 88-94, 1997-01-10
The Society of Chemical Engineers, Japan