CO₂ Discharged from a Compound Micro-grid of a Hydrogenation City Gas Engine and a Fuel Cell

Abstract

The introduction to a urban area of a micro-grid has the following advantages: (a) The heat transport distance is short, and effective use of the exhaust heat of the generating equipment is possible; (b) the optimal facility for the energy demand characteristic of a community is installed, and a system having small environmental impact can be built; and (c) with an independent micro-grid, the scale of equipment for distributing electricity is small [21–23]. Furthermore, (d) connecting renewable energy considering regionality is expected to become an advanced system in micro-grid technology. At present, the method of a micro-grid interconnecting with commercial power, etc., is being investigated (interconnect microgrid) [23]. However, in order to achieve the advantages of (a)-(d) described above, it is necessary to operate a micro-grid independently. The subjects of the independent micro-grid are back-up in the case of overload and securing of power quality (voltage and frequency). Furthermore, it is necessary to clarify the power generation efficiency, the carbon dioxide emissions, and the power cost of an independent micro-grid. An improvement in power generation efficiency is expected from the independent micro-grid using a fuel cell compared with conventional electric power-supply technology. However, at the moment, fuel cells are expensive and whether they will spread is not clear. As for a fuel cell independent micro-grid, power-generation efficiency and carbon dioxide emissions are expected to be advantageous compared with existing generating equipment.