[RE-wrenches] kW/MW v. kWh/MWh

[Dan Fink]

Hello Marco.
No d'oh!
Your assessment is correct; you can't store kilowatts of power, you 
*can* store kilowatt hours of energy.
Author Lyn Corum might have slipped up a couple times in there and 
dropped an 'h' from the kw, but maybe not -- because when storing energy 
on a utility scale, the engineers are greatly concerned with how fast 
the energy can come in, and how fast they can send it out. So when they 
refer to a '50 kw flywheel storage unit,' that often means the max power 
coming in or out at any given instant.
In our (comparatively) puny end of the energy storage business, 
batteries, we rarely have to deal with the issue. Assuming our battery 
bank is big enough to keep the charge or discharge rate below C10, or 
even C1, we just stack more inverters.
DAN FINK



Marco Mangelsdorf wrote:
> I’m reading a piece on energy storage in the latest issue of Distributed 
> Energy mag.
> 
>  
> 
> The writer, Lyn Corum, repeatedly refers to the capacity of storage 
> mediums (thermal, compressed air, flywheel, battery) in kW and MW terms.
> 
>  
> 
> Heck, even my friends at Beacon Power refer to their flywheel systems in 
> MW terms.
> 
>  
> 
> Am I missing something here?  Shouldn’t all references to energy storage 
> be in kWh and MWh terms?
> 
>  
> 
> Or am I experiencing a d’oh! moment?
> 
>  
> 
> Marco
> 
> ProVision Solar
> 
>  
> 
> 
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