It is only irrelevant if the excess daytime generation exceeds the
night consumption. If your generation excess equals 100% of the night
time use but you use 50% of that to power the weight lift, you run out
of power. Efficiency is a factor. If you make enough to lift the
weight and carry 100% of the night load, then no, not a factor.
The company I worked for installed the Trabon lubrication system before
the system went operational and I tagged along with the crew one day on
the excuse that I was going to check the controllers. It was impressive
if nothing else. It was also a little eerie to know the lake was on top
of you with only the penstocks keeping you dry.
I was sort of jealous. They had workstations scattered throughout with
every Rigid tool know to man. That was over 40 years ago and I imagine
the shine has worn off a bit.
What's the efficiency of pumped water?
What's the (end to end) efficiency of electrochemical battery storage?
The U.S. Department of Energy has big plans for battery systems like
this. Pumped hydro is the most cost-effective way to store electricity.
Ninety-nine percent of the bulk electric storage in the world is pumped
hydro, and by 2050 the department wants to nearly double the amount now
produced: enough to serve nearly 25 million homes.
The only efficiencies that come into play are the frictional losses
and motor efficiency of the winch, and the frictional losses in the
flywheel mechanism. all the rest of the energy expended lifting the
weight is recouped as the weight falls.
On Monday, May 22, 2017 at 11:26:29 AM UTC-4, firstname.lastname@example.org wrote:
There's more to efficiency than that. What about the losses going
from electric energy to mechanical in the motor/generator and then
again when the process is reversed? That's significant.
Losses in wiring, not so significant if it's a small home size system,
but if it's over any distance, then it is.
Motor efficiency has improved and NEMA Premium can be in the 95% range.
I don't know what the total losses in the system would be, but it is in
the "no free lunch" category. You need enough generation to cover it
adding to the cost of equipment.
For large-scale public power supply, the efficiency that really matters
is economic: would it cost less to build, operate, and maintain some
energy storage system than to use gas turbines to take up the slack when
solar and wind generation drop off?
The turbines have to grow to continue to meet growth in peak usage.
The fixed costs of a turbine continue even when it's turned off.
"Sorry Charlie, load is light tonight, you get to go home early without
pay. Maybe we'll need you tomorrow, or maybe not, stay by the phone...
if you can still afford to pay the phone bill." I'd expect that the
cost fuel is lower if you contract for a fixed amount. Short term
adjustments are gonna cost you.
This can only get worse as more unreliable power is MANDATED, like solar
and wind. If you are gonna legislate unreliable power,
somebody has to fund research/development for storage.
Yep, as soon as you can get complete systems that can supply ALL
your needs at a competitive
cost/KWH (including debt retirement and depreciation)
without subsidies or requiring the grid to back
you up or swallow your excess, the market will explode.
When do you think that will be?
compressed air is being used some places.
i thought it would be interesting if you could
split water using the extra electricity and
store the O2 and H under inverted glass bells
submerged in water. then the gases could be
used to run a fuel cell generator (either 24/7 or
just at night) and the water could drip back into
the containers to be split again (completely closed
Seems like a lot of loss due to heating on compression
and cooling during release. Would be interesting to see
Can't supply a link, but there was a thread a while back
about a guy who did something similar. Only he just stored
the Brown's gas and burned it for light and heat.
Seems like a very dangerous thing to do. Don't remember
how the efficiency compared to battery storage. Might be
attractive in the post apocalyptic world where replacement
batteries aren't available.
As I recall, the efficiency of electrolysis at low temperatures
is rather low.
Even though it's safer to store the gasses separately,
I'd be very nervous if my neighbor decided to embark on
such a project. Life is already too short.
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