Solar System Controlled in Accordance With Weather Conditions

2014/08/01 16:16
Kenji Kaneko, Nikkei BP CleanTech Institute
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A significant number of systems that optimally control solar power systems in accordance with weather conditions by combining solar power generation and rechargeable batteries were proposed at PVJapan2014.

PVJapan2014 is a trade show on renewable energy-related products especially for solar power generation and runs from July 30 to Aug 1, 2014, in Tokyo.

TMEIC's 'Smart PV'

Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC) exhibited a technology called "Smart PV," which prevents sudden output fluctuations at mega (large-scale) solar power plants by optimally controlling PV inverters and storage batteries.

In Hokkaido, where the capacities of power grids are relatively small, the number of mega solar plants (which cause large fluctuations) connected to grids is rapidly increasing, and the impact of sudden output fluctuations on the grids is becoming a problem.

TMEIC has already developed the "Main Site Controller (MSC)," which integrally controls multiple PV inverters at a mega-solar power plant to maximize the amount of electricity sold. The Smart PV prevents sudden output fluctuations by integrally controlling the MSC and large-capacity storage batteries.

At the time of a rapid output increase, the MSC is used to reduce the output. And, at the time of a rapid power decline, the batteries discharge electricity to smooth the output. Compared with the case where only storage batteries are used to smooth the output, the use of the MSC enables to reduce the capacity of storage batteries by about half and initial facility costs.

Hokkaido Electric Power Co Inc requires that the output fluctuation of a mega solar plant be within 1% (per minute) of the rated output of the plant. When the Smart PV, which combines the MSC and storage batteries, is used for a 5MW solar plant, the rate of change can be achieved by installing about 2.5MW of storage batteries, TMEIC said.

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