

Shipping containers of Li-ion batteries in the power grid - davi
http://green.blogs.nytimes.com/2011/01/07/hold-that-megawatt

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bradleyland
I was rather surprised that the energy transfer loss is only 10% in batteries,
but 15% in flywheels. It's pretty amazing that the chemical process in a li-
ion battery (developed in the last 50 years) is more efficient than our best
engineering efforts in the simple wheel and axle design (over 5500 years old).

On a side note, an engineer at our local power plant once told me that the
inertial energy available on "the grid" was sufficient to cause one of the
steam turbines at our local power plant to "jump out of the floor" should
someone fully engage it out of phase.

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stcredzero
The US might benefit from some investment in Nickel-Iron batteries. These were
invented by Edison in 1901. They have a basic service life of 20 years (as
opposed to 3-5 for Li-ion) and can be stretched to 50 years with electrolyte
replacement. The battery tech is worked out, but investments in manufacture
and economies of scale would enable market access to a technology with lower
cost than Li-ion. (Also, the materials used in NiFe batteries are cheap and
available domestically. They are a bit challenged with regards to high
currents, though.)

 _Wind and solar plants “introduce some additional variability that you don’t
have with traditional thermal units,’’ Mr. Zaharuncik said. With a system that
has a lot of renewable energy generators, he explained, “you need some other
kind of resource that complements it. ‘’_

I'm surprised that flywheels aren't a bigger deal because of wind and solar
power. Why doesn't someone make a flywheel unit the size of a major appliance,
incorporating inverters and regulating hardware, for home wind and solar?

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AaronM
At the last company I worked for, which was a manufacturing facility. They
installed a giant flywheel as a line conditioning device. (We manufactured
NAS, and it is terribly costly when a power outage interrupts 5 days worth of
testing forcing you to start over). I think it gave us about 17-18 seconds of
power, in the event of any brief interruptions in power (Most of the outages
we received were 1-2 seconds in length)

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aristus
Some datacenters (eg the Miami IPX/NAP) use flywheels the size of large trucks
to provide failover until the generators kick in. They are seriously scary
machines up close.

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cagenut
AES did a pilot project of the same type with Altairnano batteries back in 08,
you can see some of the numbers and details here (warning pdf):
[http://www.b2i.cc/Document/546/KEMA_Carina_validation_report...](http://www.b2i.cc/Document/546/KEMA_Carina_validation_report_public_final.pdf)

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chopsueyar
What about some sort of hydraulic "battery"? I have seen water pumps that can
be used as generators and vice/versa, especially during offpeak periods, water
is pumped uphill, and during peak demand, water is sent downhill to generate
electricity.

Would a hydraulic turbine/pump/generator be feasible?

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cryptorchidism
Well yes, and that's what the system you mentioned does. In addition to pumped
hydro, there are schemes for pumping air into underground caverns.

You need too much volume to make artificial tanks cost-effective. That's why
natural formations are used.

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chopsueyar
That pneumatic system sounds interesting. Do you have any links, por favor?

