The energy-storing capacity of hydrogen may create enormous energy security benefits for islands using hydrogen energy. Social acceptability of hydrogen has been extensively studied globally in terms of its safety concerns, whereas existing Japanese literature in the area is very limited. This study conducted a questionnaire survey that examined the social acceptance of hydrogen stations among islanders in Nakajimacho, Ehime, Japan. The acceptance of hydrogen stations (HSs) was mainly determined by personal value. Renewables-based local production of hydrogen was predicted to bring more safety and an environmental improvement impact, whereas fossil fuel-based, transported hydrogen was predicted to have more of an economic development and energy security impact. At the same time, local people accepted HSs more when they predicted that installation of HSs would provide local social benefits, whether or not hydrogen was based on local production from renewables or transported fossil fuels. The result would be of value in examining the viability of the introduction of hydrogen energy in Japanese islands with an aging population.

Structures such as Wave-dissipating blocks, which were constructed in large scale projects about 30 years ago, are scheduled to be removed as the project ends. However, large corals inhabited the quiet waters formed by these structures, and it seemed to be functioning as a source of coral larvae to the surrounding sea area. And the biodiversity of the entire sea area might be increased by this specific environment. In this case, the natural environment of the area would be preserved better by leaving these structures. But, it is difficult to predict and evaluate this in the assessment at the beginning of the project. It is necessary to seek conservation measures based on the voluntary assessment with the evaluation by the expert opinion committee, and other laws and regulations (the Natural Parks Act, Fisheries Resources Protection Act etc).

There are many cases where alternative plans of the stack height are compared at the stage of the Document on Primary Environmental Impact Consideration. Almost no difference, however, exists in the prediction results of air pollutants concentration among alternative plans. In this paper, an appropriate approach for the examination of alternative plans of the stack heights is proposed based on the survey of Environmental Impact Statements and the calculation of atmospheric dispersion considering unique meteorological conditions such as building downwash, stack tip downwash, fumigation and atmospheric inversion. As a result of the low stack heights of 50 - 60 m, the effects of unique meteorological conditions cause a meaningful increase of air pollutants concentration. Examination of alternative plans is required for a low stack.