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Micro gas turbines (MGTs) are subject to certain problems, notably low thermal efficiency of the system and high emission including NOx. The chemically recuperated gas turbine (CRGT) system introduced in this paper is one of the most promising solutions to these problems. The CRGT system we propose uses an endothermic reaction of methane steam reforming for heat recovery. It is usually thought that the reaction of methane steam reforming does not occur sufficiently to recover heat at the temperature of turbine exhaust, but we confirmed sufficient reaction occurred at such low temperature and that applications of the chemical recuperation system to some commercial MGTs are effective for increasing the efficiency.

It has been an important target to realize a sustainable energy usage in the future, regardless of the country. Japan is now compelled to consider a new paradigm of energy policy due to the nuclear power plant failures after March 11, 2011. To discuss the ideal or a favorable future of Japan's energy, understanding the present status as well as the available energy options in the future will be an initial step, followed by discussion of the issues related to each option. The aim of this article is to summarize the present status of Japan's energy systems and to clarify the major points of discussions for the realization of future sustainable energy systems. In addition, the major options of both energy supply and demand sides are summarized. The issues for realizing the future energy systems are discussed from the large-scale penetration of renewable systems, the demand side energy management and savings, the mobility, and the centralized electricity grid viewpoints, to provide a common basis for the discussion of future energy systems in Japan.

The use of the Active Carbon Recycling Energy System in ironmaking (iACRES) has been proposed for reducing CO2 emissions. To evaluate the performance of iACRES quantitatively, a process flow diagram of a blast furnace model with iACRES was developed using Aspen Plus, a chemical process simulator. The CO2 emission reduction and exergy analysis was predicted by using the mass and energy balance obtained from the simulation results. iACRES used a solid oxide electrolysis cell (SOEC) with CO2 capture and separation (CCS), an SOEC without CCS, and a reverse water-gas shift reactor as the CO2 reduction reactor powered by a high-temperature gas-cooled reactor. iACRES could provide a CO2 emission reduction of 3-11% by recycling carbon monoxide and hydrogen, whereas the effective exergy ratio decreased in all cases.

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