Beacon Power has bought advanced flywheel energy storage technology from Hanyang University in Korea. Photo credit: HSCL
Energy storage news headlines from our Twitter feed over the last week.
- Energy Storage USA 2014, a new event focusing specifically at commercialisation in the world’s most promising energy storage market, will take place this June. See the event web site for details on the programme, attending, speaking or sponsoring.
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We analyse recent developments in flywheel energy storage: from established companies such as Beacon Power and ABB, to startups like Temporal Power and Flybrid. Photo: NASA
With all the hoo-hah around the developing nexus between Tesla, SolarCity and Panasonic, the battery subsidies on offer in Japan, plus NEC’s buyout of the A123 Systems grid energy storage unit from Wanxiang, you could be forgiven for thinking battery storage was the only game in town. But there is another technology that can provide some forms of grid-scale energy storage that batteries are less suited to, and which may one day even find its way into mass-produced hybrid cars.
Flywheels store kinetic energy that can be supplied either directly or via an electric motor, acting as a generator once the retained energy needs to be recovered.
The amount of energy that can be stored is a function of the mass of the disk, multiplied by the square of its rotational speed.
As a result, faster spinning wheels are a way of dramatically increasing capacity without the need to upscale the size of the unit (but speeding has its penalties, as we’ll see later).
Magnetic bearings are used to reduce friction and the flywheel is sealed in a vacuum to eliminate air drag. These two elements, plus the use of carbon composites in some of the faster flywheels, add to the cost of the current technology.
Flywheels are not much use at storing large amounts of energy for long periods of time. Applications such as load shifting and energy arbitrage are probably better suited to other technologies.
However, flywheels are in commercial use, there are a number of interesting development projects in the pipeline, and they could become a lot more common.
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Laurel Mountain, West Virginia – A previous collaborative project between AES and PJM. Photo from AES Corporation.
US grid operator PJM Interconnection, whose operations serves 60 million Americans across the Midwest and northeast of the country, has hit the renewables headlines twice this week for signing up to two separate energy storage deals.
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