Hachinohe Microgrid

The Hachinohe Project in Aomori Prefecture was part of the Regional Power Grid with Renewable Energy Resource Project funded by the NEDO. It operated from October 2005 to March 2008. The project was a collaboration between Hachinohe city, Mitsubishi Research Institute, and Mitsubishi Electric.

NEDO’s main goal for this project was to develop an optimum operation and control system, evaluate PQR, cost effectiveness, and GHG emission reductions. Meanwhile, the local governments wanted to construct a new industrial innovation zone centered on environmental and energy technologies.

The central feature of the system is that only renewable energy sources are used to supply electricity and heat. The supply sources include two 50 kW and three 10 kW solar PV systems, small wind turbines, a 100 kW lead-acid battery bank, and three 170 kW gas engines fed by sewage and waste gas by-product. At the sewage plant, a 907 kg/h wood-waste steam boiler was installed to supply heat to protect the bacteria, and exhaust heat from the gas engines was reused in the gas fermentation process.

The TOBU sewage plant treatment system was controlled by an information exchange network. The electricity produced was transmitted to schools, the local city hall, and an office building by a private distribution line 5.4-km, 6 kV feeder, and the whole system connected to grid at a point of common coupling. The energy management system was developed to meet demands for both electricity and heat, while minimizing operation costs and CO2 emissions.

Islanding operation was performed for one week in 2007, the purpose of which was to evaluate the ability of the system to maintain and control power qualities. The project is no longer in operation due to funding shortage.