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Japanese companies are building some of the world's biggest battery systems to address one of solar power's biggest problems–its volatility.
Handling the surges in power when the sun shines and storing that energy for use when it is cloudy or dark is a major headache for solar power producers and the utilities they supply.
Mitsubishi Electric Corp and NGK Insulators Ltd. are assembling a 50,000 kilowatt battery system for Kyushu Electric Power Co to study ways to better accommodate solar power.
A slightly smaller, 40,000 kilowatt battery system is under construction in Minami Soma, north of the Fukushima Daiichi nuclear power plant, for Tohoku Electric Power Co. to conduct similar research.
The government is financing both projects at a total cost of ¥31.7 billion ($257 million), a government official said.
Original Submission
(Score: 4, Informative) by gnuman on Saturday June 27 2015, @05:21AM
40,000kW is called 40MW.
Also, that is not how battery capacity is indicated. Watt is a unit of power, not energy.
(Score: 0) by Anonymous Coward on Saturday June 27 2015, @05:32AM
Yeah, UPS capacity is always indicated in volt-amps, which are literally the same units as watt-the-fucks.
(Score: 3, Informative) by Anonymous Coward on Saturday June 27 2015, @08:24AM
That would be power, not capacity, and VA is not necessarily the same as W when talking about alternating current. W is the real or active power, VA is the apparent power. The ratio between the two is called power factor. A purely resistive load (an incandescent light bulb, for example) has a power factor of one. Most electronic loads (switching PSUs, for example) have a power factor other than one. The UPS, wires, switches and everything else in the circuit needs to be designed for the apparent power, not just the real power. That's why you'll find VA, not W, on type plates of electric devices.
(Score: 0) by Anonymous Coward on Saturday June 27 2015, @07:50AM
The purpose of the batteries is to supply power when the sun doesn't. Units of power are actually appropriate here, although I agree about using MW.
(Score: 1, Funny) by Anonymous Coward on Saturday June 27 2015, @08:02AM
It should be 0.04 jiggawatts.
(Score: 2, Informative) by Anonymous Coward on Saturday June 27 2015, @08:43AM
As is often the case, a single number doesn't sufficiently describe a complex system. Usually you want to know at least two things about a battery: How much energy it can store and how fast you can get it out of the battery. Often you also need to know the rate at which the battery can accept charge, which can be much lower than the discharge rate. Other important metrics are total lifetime (in years and/or number of charge-discharge cycles), energy density and power density (per weight and/or volume). Some people may also be interested in the costs.
Anyway, the battery system that the article is about is rated for 50MW output and a 300MWh capacity (the article links to a PDF in Japanese which has the information).