Big battery eyed as green energy cure

Six-story Hokkaido cell to keep power flowing on dark, windless days


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.

  • Actually the power does not need to be wheeled to Tokyo; it only needs to incrementally offset that power which would otherwise have gone to a neighbouring prefecture. There may be costs associated with it, but not as much as indicated. If there are plans for a Y1trillion investments, its probable that its needed by the system anyway.

    • Starviking

      But then there would need to be updates of the Hokkaido load-balancing system. More giant batteries and energy storage dams at least, probably more back-up power plants for periods when solar is under-producing.

  • Jeffrey

    ““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.”

    Better idea: Build more solar and wind closer to Tokyo and tap into exist grid. Energy production needs to be as localized as possible.

    • Sam Gilman

      Alas, I’m afraid, you need to have wind and solar spread out over large distances to even out the lack of wind and sun in a specific area. You need turbines to be large, not small. Most of all, you need more solar where it’s sunnier, and more wind power where it’s windier, otherwise you’re wasting resources.

      The article refers to Hokkaido’s “fair weather”. Does anyone have any data on that? I would have thought it got less sun than further South. (Hokkaido has lots more unused and underused land, however, which makes renewables more attractive there than elsewhere.)

      • The only reason to spread out is really complaints by landowners; Japan is not so far from a population centre to worry about demand distribution for small schemes. You don’t have to ‘fill the void’, as coal & pumpstorage do that, gas-fired peaking, hydro plants and these renewables plants (using these batteries) will fill the peak loads. There is also spilling reserve (possibly old oil-gas or fired plants) also. If you want data on total sunshine hours go to the meteorology website. Bear in mind that its not simply an issue of total sunshine hours. As you go north, there is less direct sunlight and more scattered sunlight because the sun is oblique on the horizon, so more refraction in the atmosphere.

    • The reason why the turbines are in Hokkaido is because the wind conditions are consistently strong there, as well as cheap land, and low population density. These turbines are not popular for many people. There is a loss of capacity despatching to Tokyo, but then its incremental, not ‘absolute’. i.e. Displacing other capacity. Yes, you will probably find (like NZ) that Hokkaido also has the most sunlight in a year.

  • Sam Gilman

    If we can get these batteries to work, it will be a fantastic step forward. We cannot use renewables on a substantial scale without storage to smooth out the intermittency. I’ve read that these batteries, unlike most others, can actually hold charge for a long enough amount of time, and have a much longer life in terms of charge-recharge cycles. However, I have a few questions.

    If these batteries are going to make renewables viable at a larger scale, does anyone know how large they’d have to be to cover, say, Hokkaido’s entire electricity needs for three days?

    I understand one of the limitations of vanadium redux flow batteries is that they only work within a certain range of temperatures, and Hokkaido gets very cold (ie below the functional temperature.) What’s happening with that?

    In terms of having a lot of acid sloshing around, how easy is it to make these things earthquake proof, and how toxic is the stuff should it leak out?

    • Sam, I don’t think they are intended to function as a ‘capacity/load reserve’, more as a ‘modulator’ of the load. A wind gust, a sudden emergency of sunshine, and that can create a ‘rush of current’. Now, if you have a lot of these wind turbines, solar panels, people using load at different times, then you need regulation in order to accomodate that type of capacity, even if there is averaging..there is unpredictability. Now, they might also use these batteries for load shifting, i.e. Cloudy or ‘still’ days, they would buy up cheap coal-fired plant capacity (burning 24hours a day) at night and shed that during peak morning times before peak sun/wind. I don’t think the capacity of the facility would be sufficient for storage. Japan would have enough of that with hydro plants. If they didn’t, it would make more sense to build a pumpstorage for that purpose. They probably simply insulate the batteries; but they might heat the electrolytes..if that’s an issue. I understand the appeal of this type of battery is the low toxicity of Vd & Bromide. Maybe that is compared to lead-acid though.

      • Sam Gilman

        Thanks. Apparently Japan doesn’t have much more left in the way of hydro to develop, so storage options (as a way of weaning ourselves properly off things like baseload coal) are still a challenge, as far as I can see.

      • I would argue that Japan has a lot of mini-hydro capacity…if any readers are next to a stream with a regular water flow and a 1-2m vertical drop. That’s all it takes to live off grid. Of course that’s too much work for the Tepco’s of the world. Hokkaido with its Spring flaw is particularly well-suited to this, as well as pairing with wind or solar. Japan, by channelling drainage courses has already done a lot of the work to create potential hydro schemes.

  • Eric

    Sounds like a step in the right direction.
    Maybe Hokkaido should be looking for industry to soak up some of power. I imagine cities like Yubari would be giving away land if a major employer wanted to build a plant.