[RE-wrenches] Solar and pumped hydro

[Mick Abraham]

Nicely informative reply as usual, Jay. One thing about a gravity based
energy storage system is: gravity cannot ever wear out, unlike (insert
expletive here) chemical batteries. The pump and/or hydro generating gear
could wear out in a "pumped storage" situation, of course...but still would
probably require intervention/replacement far less often per unit of stored
energy. Isn't it amazing how often chemical batteries continue to
disappoint? I'm over that...so an idea like Keith's is bound to keep coming
up.

Mick Abraham, Proprietor
www.abrahamsolar.com

Voice: 970-731-4675


On Mon, Aug 24, 2009 at 7:11 PM, jay peltz <jay at asis.com> wrote:

> Hi Keith,
> I get this question a lot.
>
>
> 1. Best efficiency for a hydro from potential energy in to actual output
> watts( not including wire loss) is around 40-60% depending on the exact
> application, turbine etc.
>
> 2. Efficiencies of pumps, is around the same at best.
>
> 3. This won't replace the battery for off grid usage.  Thats the short
> version, the long answer if needed.
>
> 4. While hydro is magic if you've got it, pumped storage
>
> 5. So we've got some big loss's, 35% efficient at best and 15% at worst. IE
> batteries are way more efficient than pumped storage.
>
> jay
>
> peltz  Power
>
>
>
>
> On Aug 24, 2009, at 11:43 AM, Keith Cronin wrote:
>
>  Hi
>
> Have any of you considered using PV to pump water to a holding area and
> releasing it and capturing the kinetic energy via a pelton wheel/hydro?
>
> If so, what do we think are the efficiencies and value of doing such a
> project are? Meaning, back of the napkin, PV is + - 77% efficient, minus "x"
> to pump the water to "x" elevation and the net result of the hydro = "____%
> efficient"
>
> It would be using the reservoir as the battery.
>
> There is approximately 300' of elevation from the PV system and water
> source to the reservoir area.
>
> I recall about 15 years ago, I visited a member on this lists Vermont home
> and he had a pond at the top of his property, but i don't recall how the
> source got to the reservoir? Might have been naturally fed?
>
> Anyway, the premise is, as grid access becomes more difficult to do, as the
> utility infrastructure gets saturated, what are our options for folks that
> want PV, but are limited in how much they are allowed to connect to the
> grid, without an interconnection study by a 3rd party to increase the
> comfort of the utility to have more non firm resources on their grid. We are
> seeing this happen here now and I was wondering if any of you have
> encountered this or are anticipating this in your areas?
>
> Any suggestions, calcs, recommendations, feedback would be appreciated.
>
> Keith
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