Beacon Power Scores Another Test System Success (NY ISO)

The main competitor to flywheel storage will be new nanotech ultracapacitors, but it looks like Beacon has so far opened a year's worth of leadtime in the certification game that should ensure them some market share in storing power off-peak and returning it to the grid when it is in demand.

FWIW.

I've heard of flywheels being considered for vehicles, but never on a large-scale application such as a power station.

It sounds like a good idea. I wonder how efficient it is?

And as for the capacitors, is the idea to store energy as DC? Seems to me to be even more inefficient.

...they currently don't have their specsheets up for the single units (they seem to have purged all mention of the 6KWh unit from the site as they are pushing forward with the 25KWh unit, which is still under development. The 6Kwh units were used in the test IIRC.) When they did I recall digging around to find that the round-trip energy efficiency was in the 90%+ range. I don't remember exactly but I seem to recall in the high 90s.

While the ultracaps do pay a penalty in DC/AC convertor efficiency, those can be made very efficient too. There's a company touting a 4KV trash-barrel-sized ultracap but they are being super-secretive. Ultracap energy storage capability goes up with the square of the voltage the ultracap can store (times the F of the capacitor.) As far as what's on the market and verifiable now the latest is an 18F 390V ultracap that was recently announced by Maxwell, aimed at the hybrid vehicle market for use in regenerative braking, as well as other vehicle and robotics applications. It's 282 watt-hours (at 1 to 1/2V duty cycle) in what looks to be something a bit bigger than an external disk drive case, though pictures could be misleading:



http://www.maxwell.com//ultracapacitors/products/modules/bmod0018-390v.asp

I tried to download the full specs on that but it hosed my browser at the time.

I cringe to look at the price tag on either the flywheels or ultracaps, though.

The unit above is probably a bit bulkier (though perhaps lighter) than the equivalent latest-greatest nanotech Li-Ion batteries, but with a much larger durability as far as frequent discharging/charging and high power loads (and the new batteries are no slackers in that department either; they beat out the last generation by an order of magnitude.) I think both the batteries and the ultracaps will have a complementary role in vehicles, unless the ultracaps make a huge and sudden jump in affordability and energy density. The ultracaps front-end the batteries to smooth the minute-by-minute load into/out of the battery pack. It's yet to be seen whether for large scale power grid storage the flywheels and ultracaps will find a way to compliment each other (different reactive power profiles) or go head-to-head in competition.

n/t