Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC) exhibited a technology to optimally combine storage batteries with a mega-solar (large-scale solar) power plant at the 4th Int'l Smart Grid Expo.
TMEIC calls the technology "Smart PV." The event runs from Feb 26 to 28, 2014, in Tokyo.
To build a mega-solar power plant in certain regions including Hokkaido and Okinawa, where the capacity of power grid is relatively small, business operators are required to prevent precipitous output fluctuation by installing storage batteries. And the Smart PV is a technology that realizes it with as small a total capacity of rechargeable batteries as possible.
The prevention of precipitous output fluctuation is realized by linking the "main site controller," which optimizes the outputs of PV inverters for an entire mega-solar plant, and the control of storage batteries' PV inverters.
The main site controller is a control system that coordinates multiple PV inverters of a mega-solar plant. It is gaining attention from power companies that need to stabilize their power grids as a system that enables to easily control the output of a mega-solar plant.
In case that some of the solar panels of a mega-solar plant are shadowed and the outputs of the PV inverters connected to the panels lower, if the other PV inverters connected to the other panels can generate outputs higher than their rated outputs, the surplus electricity is sold as it is, enabling to keep the total amount of electricity being sold.
By combining the main site controller and rechargeable batteries, it becomes possible to reduce the total capacity of rechargeable batteries used to prevent precipitous output fluctuation at a mega-solar plant. Hokkaido Electric Power Co Inc set a target of using 4MW of rechargeable batteries for a 5MW solar plant. However, with the Smart PV, the total capacity of the batteries can be reduced to about 2.5MW, TMEIC said.