Few Considerations on Problems of CO 2 Geological Storage with Carbon Circulation and Proposal of An Integrated Regional Energy System considering Low Carbon Society

Abstract

1．緒 言 IPCC (2013) 1) のレポートに基づいて著者らが作成した地球規 模での炭素循環の概念を Fig. 1 に示す。大気，海洋，地中 (地下) における CO 2 ガスのおおまかな量的バランスを Table 1 および Fig. 2 に示す。とくに，排出量と吸収・削減量として大きな割合 を持つものが植物関連であり，陸域の土壌から大気中に放散され ている CO 2 が年 2000 憶 ton 強と見積もられていることが注目さ れる。地球上の全土壌中には，大気中の CO 2 の約 2 倍あるいは 陸上の植物バイオマスの約 3 倍に相当する約 1 兆 5000 億 ton の 炭素が存在すると見積もられており，CO 2 ガスの土壌から大気 The development and advancement of new technologies have been considered for carbon fixation and its effective utilization as being indispensable for the achievement of greenhouse gas emissions reduction targets without adversely impacting economic growth in the world. Among such technologies, the one considered to present the greatest potential in terms of both of feasibility and CO 2 reduction, as well as offering a relatively low cost burden, is CO 2 capture, usage and geological storage (CCUS). The costs of CO 2 recovery present a barrier to carry the CCS and CCUS project. Large-scale project models for carbon sequestration, recovery and underground storage that involve the construction of long-distance pipelines have been either implemented or planned in North America and Australia, etc., but such projects are not well matched to the land conditions of Japan. The development of Japanese-style CO 2 sequestration, recovery and underground storage technologies is required that ensures linkage in a compact and high economical way among local area-based CO 2 recovery, storage or fixation processes and also energy supply. In this article, the concept "Low-Carbon Smart Cities" have been proposed with some technical challenges that can be solved by research developments with including environmental monitoring. This concept is targeted for areas with relatively high population density and where land use constraints are in place. By applying the resulting model to the situation in Southeast Asian countries, which have similar land conditions and also possess coal resources, the aim is to combine and integrate the local environment with the provision of carbon-free energy and realize CO 2 reduction with greater economic efficiency.