Evaluation of energy technologies to realize sustainable systems.

Degradation of the global environment and depletion of resources are threatening sustainable development of mankind. In particular, climate change caused by increasing greenhouse gases is one of the most serious issues in analyzing energy systems. This paper aims at proposing frameworks to investigate sustainability and at evaluating technologies for sustainable energy systems. For this purpose, we first define the index of sustainable limits on resource depletion and emissions. Sustainability of mineral and energy resources is evaluated based on the index. Estimations indicate that energy resources and CO2 are unsustainable, and that we should introduce technologies to reduce energy consumption and CO2 emissions. Life cycle energy requirements are assessed for photovoltaic systems as representatives of the technologies. Through the life cycle assessment, we quantitatively evaluate measures to improve life cycle energy requirements and capital costs. At the same time, we clarify the direction of research and development required for technologies to realize sustainable energy systems. © 1999 Scripta Technica, Electr Eng Jpn, 130(2): 25–31, 2000 [ABSTRACT FROM AUTHOR]