Japan will build the world’s largest storage battery system in Hokkaido as early as this autumn in a bid to rectify fluctuations in the electricity produced by renewable energy sources.
The project is aimed at promoting renewable energy by addressing a key defect — inconsistent power generation.
The nation’s utilities are required to buy electricity generated by solar, wind and other green power sources at fixed prices under the feed-in tariff system introduced in July 2012.
But the electricity generated by such sources accounts for only 1.6 percent of the nation’s total, partly because solar and wind power are dependent on the vagaries of the weather.
To raise renewable energy’s role the national energy mix, the Ministry of Economy, Trade and Industry pushed for the development of a large storage system that would store electricity when weather conditions are favorable and dispense it when the weather fails.
Sumitomo Electric Industries Ltd. and Hokkaido Electric Power Co. are leading the storage project, and the ministry has provided ¥20 billion to cover all development and manufacturing costs.
“A subsidy in full is the exception of exceptions,” a senior METI official said.
For the project, Hokkaido Electric will build what is called a “redox flow” battery system, produced by Sumitomo, at a substation in the town of Abira. With a capacity of 60,000 kwh, the system will be as high as a six-story building.
A redox flow battery repeats charging and discharging operations in a tank, using an electrolytic solution of vanadium. While it is safe and has a life span of 10 to 20 years, it can be readily converted into a large system, experts say.
The ministry believes that using such batteries will allow utilities to buy 10 percent more electricity from green energy sources.
Nevertheless, there remain many hurdles before renewable energy proliferates. The feed-in tariff system, for example, has drawn a flurry of solar power companies to Hokkaido interested in its ample land and fair weather. Hokkaido Electric, however, can only buy around 400,000 kw from large solar systems, each of which can generate 2 megawatts or more. That has left a glut of 1,565,000 kw available for sale.
To make use of the excess, the utility must build a grid to transmit it to the Tokyo metropolitan area. But Ryuichi Yokoyama, a professor at Waseda University’s Faculty of Science and Engineering, says building such a grid would come at a high cost.
“Surplus electricity in Hokkaido can be sent for use in Tokyo if a total of ¥1 trillion is spent,” he said, calling for the government to take the initiative in building such grids.
Yokoyama also said renewable energy may dismantle the utilities’ regional monopolies and raise green energy’s share of national electricity output to 15 percent, depending on government measures.