So why is this important? First, a bit of background info:
From renewableenergyworld.com:
Energy storage technologies are often referred to as a way to shift time and smooth the delivery of renewable energy such as wind and solar. But the cost of energy storage infrastructure is not insignificant. Today's cost for advanced lithium batteries (one of the leading energy storage candidates) capable of storing 1 MWh of electricity is about $2 million, about the same capital cost per megawatt-hour as the wind turbine. So if a 1 MW-rated turbine has good wind and is able to produce its megawatt hour rating for 10 hours it will produce 10 MWh of energy. Storing this energy would require $20 million worth of batteries. This obviously is not an economic model.
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The need for frequency regulation is the main reason that power generators have to match supply to demand. It would sometimes be easier simply to create more electricity than is being demanded. But this is more dangerous than not supplying enough electricity. When there is more supply of electricity than is demanded the frequency of the alternating current goes above 60 Hz and when the supply is exceeded by demand the frequency drops below 60 Hz. (In Europe and other parts of the world this standard is 50 Hz.) Electric companies are mandated by federal laws to maintain 60 Hz on the grid. The bigger the disparity above or below 60 Hz the larger the fines that may be imposed on them.
Power companies are used to having a deterministic supply side. If they tell a supplier to fire up a turbine that is rated for 30 MW they can count on having 30 MW delivered within the contracted time with near certainty. With wind and solar energy, however, we are now asking the power company to deal with intermittency on their supply side and not just on their demand side. Although renewable energy sources (not counting hydroelectricity) account for less than 2 percent of the total energy generated in the United States, the popular press and politicians are talking about having 20 percent of our electricity generated by renewables within 10 years. Common sense suggests that load following and frequency regulation will become more difficult and expensive with this increase in supply side variability.
But why flywheels? And how does that work, anyways? From greenpowerresearch.com:A flywheel is a mechanical device with a significant moment of inertia used as a storage device. Flywheel Energy Storage (FES), also referred to as kinetic storage. The flywheels inertial mass is accelerated to a very high rotational speed and the energy in the system is maintained as rotational energy. The energy is converted back as needed to the desired application by slowing down the flywheel. In short, energy is stored in the rotor as rotational energy. The stored energy in a flywheel is proportional to the mass, and to the square of the tip velocity. Key features of flywheel-based regulation are its fast response (many times faster than conventional fossil fuel generators used for regulation); its high round trip efficiency (85 percent); and the fact that it produces zero direct CO2 or other emissions.
Yingli Green Energy is also working on this type of technology. From Asia Today: On September 29, the experiment sample of China's first 20 kilowatt-hour magnetic suspension energy-storage flywheel, developed by Yingli independently, was completed. This revealed some clues about the next strategic goals of Yingli. This kind of energy storage technology is a key for new energies to evolve from substitute energies into mainstream energies.
There are other applications for flywheel energy storage as well. For example, on Sept 1, 2011, Kinetic Traction Systems and Williams Grand Prix Engineering Limited (Williams F1)
announced that they have signed a long-term Co-operation Agreement to advance and promote innovative, clean flywheel-based energy storage and recycling systems for mass transit rail and grid applications.
Originally intended for use in the Kinetic Energy Recover Systems of its racing cars, Williams F1's subsidiary, Williams Hybrid Power (WHP) has developed high-performance, lightweight mobile flywheel energy storage systems. These incorporate its patented Magnetic Loaded Composite (MLC) technology which gives the systems their unique high cycling ability and high-power characteristics. WHP's mobile flywheel systems have been successfully applied in applications such as the Porsche 911 GT3 R hybrid.
KTSi's proprietary stationary GTR flywheel systems, which leverage WHP's MLC technology, capture braking energy of trains to increase performance, reduce electrical energy consumption, and lower carbon emissions for metro transit agencies around the globe.
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From the Alternative Energy Stocks blog: Hype Busters From Lux Research Explain Grid Based Energy Storage
