Toshiba Corp will supply the facilities of a next-generation electric power system for Okinawa Electric Power Company, a power company in Okinawa Prefecture, Japan.
The electric power system will come with storage batteries to stably supply electricity generated by solar panels, etc. The system will be tested in Miyakojima, Okinawa, from the autumn of 2010.
The test will be conducted by adding photovoltaic systems (3MW, 1MW) and storage batteries (4MW, 200kW) to existing facilities including two thermal power plants (21,500kW, 40,000kW), a gas turbine plant (15,000kW) and five wind plants (900kW x 4, 600kW x 1). Because the outputs from wind and photovoltaic plants sharply fluctuate, storage batteries will be used. And voltage rise, measures to deal with surplus electricity, frequency adjustment, etc will be tested.
Toshiba will provide power conditioners, communications systems and the "μEMS," a system that monitors power demand and supply, in addition to the photovoltaic systems and storage batteries.
It plans to generate 3MW of photovoltaic electricity by a mega solar power plant and 1MW at industrial plants (600kW) and residences (400kW). However, in the test, photovoltaic systems will not be set up at real plants or residences. Instead, two photovoltaic systems will be built for assumed industrial plants and residences that will act as electricity consumers in the test.
As for the storage batteries, a 4MW sodium-sulfur battery will be connected to the power grid, and a 200kW lithium-ion (Li-ion) battery will be used for the residences. Toshiba will assume that a 4kW photovoltaic system is set up at 100 houses and a 8kW Li-ion battery is provided to 25 houses.
The Li-ion battery is Toshiba's "SCiB," which uses a lithium titanate negative electrode and features a rapid charge-discharge cycle. Also, Toshiba will supply 12 power conditioners with a rated output of 250kW for the 3MW mega solar power plant. For the assumed industrial plants and residences, power conditioners with rated outputs of 10kW and 4kW, respectively, will be used.
For the photovoltaic systems, Sharp Corp's polysilicon solar cells were employed. And optical cables will be used for the communications systems. Currently, there is no plan to utilize smart meters.