Evaluation strategies for chemical and biological fixation/utilization processes of carbon dioxide

Abstract

Various chemical and biological processes have so far been proposed for carbon dioxide recovery, conversion into organic matter and reutilization, which is called the carbon recycling system. In this paper, their evaluation strategies are discussed. They are classified into two categories; with and without energy which is utilized artificially. It is clarified that most of the chemical and biological carbon dioxide fixation systems or carbon recycling systems with artificial energy should be evaluated from the energy point of view as primary and secondary energy systems, and comparing them with other alternative soft energy paths so far proposed. Chemical and biological processes which should be evaluated separately from new soft energy paths are only those which essentially require no artificial energy, such as afforestation of deserts, fertilization to ocean and utilization of rock weathering reaction.