Electricity supply project in Roppongi area and new technology incorporated in urban power plant

The amendment to the Electricity Utilities Industry Law in December 1995 in Japan created a new category of electric power supplier called "specific electric utility industry". These utilities are entities other than general electric utility industry that are allowed to supply electricity to a number of users in one or more buildings, such as office blocks, using CHP (combined heat and power) and other kinds of power sources. In Japan today, CHP has only been used to supply electricity to customers within the building where the generator is. Specific electric utility industry, however, is allowed to supply and sell electricity to the buildings outside the building where the generator is, which can not be seen anywhere else in the world. Combining CHP with conventional district heating and cooling systems (DUC) as an element of urban redevelopment projects makes it possible to create energy efficient, environmentally benign and economical energy supply systems. Systems of this kind represent the ultimate in distributed energy supply systems, and are likely to grow increasingly widespread in the future. A specific electricity supply service is being planned by Tokyo Gas for the redevelopment project in Roppongi area, in the heart of Tokyo. The power generation system, which will have a total output of 36500 kW, will be powered by steam-injection gas turbines. Although two specific electric utility industry have already been launched elsewhere in Japan, the project will be the largest of its kind in this country and the first to offer full-fledged services in an urban area. The attached heat service plant will have a capacity of 66810 kW (19000USRT), and utilize all waste heat generated in the process of power generation. Together, the power system and heat service system will consume 18% less energy and emit 25% less CO₂ and 44% less NO_x than a conventional energy supply system. This unprecedented project to build Japan\´s first ever large-scale urban power plant presents a unique set of challenges. High-capacity generator facilities will need to be installed under buildings in the center of Tokyo, and services will need not only to be economical, but also to be reliable, energy efficient and environmentally benign. The project will thus not only co- mbine conventional technologies, but also incorporate new technologies. This paper outlines the specific electricity supply project in Roppongi area, and describes the new technology that will be used for the power generation plant.