2. System components
(1) Redox flow battery (1 MW x 5 hours)
A redox flow battery is a storage battery that comprises a charging/discharging cell section and a tank full of metal ion electrolyte.
It charges/discharges through oxidation-reduction of vanadium or other ions.
The battery features long service life as the electrodes and electrolyte are not subject to deterioration even after repeated charge/discharge
operations and is easily maintained as its uses the same electrolyte in both the cathode and anode.
It also provides increased safety as it does not require any combustible substances and is operated at ambient temperatures. This battery is suitable for irregular,
highly fluctuating charge/discharge operations, enabling accurate monitoring and control of stored electric power.
Accordingly, it is an optimal storage battery for efficient use of renewable energy and surplus electricity supplied during the night.
(2) Concentrator photovoltaic (CPV) unit (maximum power generation of a total of 28 units: 200 kW)
A CPV unit is a photovoltaic system incorporating small-size photovoltaic cells for energy conversion, directing high-intensity sunlight converged by a lens to photovoltaic cells.
The power generation efficiency of the CPV panel is about twice that of silicon solar panels currently on the market as CPV cells are made from a special compound semiconductor material.
Installed at an elevated position, concentrator panels provide usable space below them.
The newly developed CPV unit offers 7.5 times greater output power (7.5 kW/unit), and yet the CPV panels are thinner and lighter than conventional ones.
(3) Energy management system (EMS)
The EMS monitors the amounts of electric power generated by a total of 28 CPV units, provided via commercial power networks,
stored in a redox flow battery, and consumed at an office or plant to manage the electric power flow.
Obtained data is sent by optical communication networks to be collectively controlled at the central control server.
This system will be used in the demonstration test held at the Yokohama to achieve optimal supply-demand balance
(maximum demand control of 1 MW) and power demand control based on preset schedules.