<<VRB technology is pretty neat. I have followed them for years and driven by their plant in Richmond, B.C. The problem with their system is ability to go very large scale.>>
VRB ..2 MW and scalable to 10 MW ...
vrbpower.com
<<The compressed air storage system that the Scientific American article proposes is actually very efficient. If you look at the email responses to the author's paper they discuss it at greater length. >>
How efficient is it?
The article states they are using Solar electrical energy, already in hand, to compress air in large underground caverns to 1100 PSI, then running compressed air with natural gas, thru massive turbines.
Seems to me the losses on DC electrical energy, already in hand, would be much larger than straight storage directly into VRB with only 20 percent DC loss round trip.The Article also speaks of DC transmission system is needed across the country.
<<They propose to phase it out over time as other storage mediums become available.>>
Why phase it IN, in the first place, if the compressing of air and the using of precious natural gas is less efficient than VRB's storage efficiency of 80 percent DC round trip?Did you look at the efficiency of gas turbines in my last post?
<<In the end it would be nice to have efficient, compact battery designs with very high energy density, low weight and volume. These are coming but we have a ways to go for very large scale grid storage at this time.>>
You already have efficiency, and large scale grid storage with VRB, at this time... they can be placed beside, or under solar instalations, and do not require underground caverns.
Being of compact design and high energy density does not matter in this area of electrical storage..so what if a 2 MW VRB occupys half a foot ball field... a 10 MW a whole football field...the important fact about VRB is that the electrolyte is good forever, you have to change two pumps every 7 or eight years and it is good for over 10,000 cycles...there is no battery available anywhere today that can cycle over 10,000 times to depth of discharge down to 20 percent as VRB can...none. |
