Multicriteria Evaluation of Biogas Plants Receiving Food Waste From a Broad Area Considering Different Spatial System Boundaries and Stakeholders

Abstract

Food waste biogas plants have multiple effects on the regional environment, economy, and society. However, the past evaluation range of biogas plants was just limited to the biogas plants themselves, such as biogas generation, methane concentration, power generation efficiency. The biogas plants seem to fulfill a variety of roles in the region, such as recycling of food waste, reduction of greenhouse gas emissions. Moreover, the effects must depend on setting the system boundary, such as objective spatial area and stakeholders. Thus, this study attempted to evaluate multiple effects of a biogas plant, as a case study, with environmental, economic, and social criteria considering different four spatial system boundaries (and stakeholders): the biogas plant itself (the company owning the biogas plant); the city with the biogas plant; prefecture including the city; and the broad area from which the biogas plant receives food wastes. The biogas plant receives food waste from households and many business entities in a broad area across the prefectures and provides the biogas to the next industrial waste incinerator. As a result of evaluation, the biogas plant reduced greenhouse gas emissions, increased the food waste usage ratio, and reduced landfilled waste. These effects were not limited to the biogas plant itself, but spread out to the city, prefecture, and the broad area. The biogas plant provided additional effects, such as the nutrient cycle (nitrogen in the compost), cost reduction in the nest industrial incinerator, new value of compost produced from the biogas plant, and job creation.