Author Topic: Virginia to Utilize Old Coal Mines for Hydropower  (Read 5852 times)

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Offline IsailedawayfromFR

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #25 on: March 24, 2017, 02:38:13 am »
It is closed from the stand point of not connected to another body of water like a river with a dam.  By permitting definition it is a closed system.  Toxins from the mines won't reach other bodies of water.

https://www.ferc.gov/whats-new/comm-meet/2014/061914/H-7.pdf
I can see it is closed from another body of water, but will still be open on evaporation and rainfall.

I wonder what happens if an inordinate amount of rainfall causes this 'closed' system to fill up past its capacity?  No way those toxins will be allowed outside the containment area unless some provision like underground injection is incorporated.

I see a lot of discussion in the Issuing Order concerning seepage from the reservoir.  If I read it correctly, it appears the entire pits will be lined to mitigate seepage?  That is an undertaking in itself.
No punishment, in my opinion, is too great, for the man who can build his greatness upon his country's ruin~  George Washington

Offline IsailedawayfromFR

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #26 on: March 24, 2017, 02:43:48 am »
Not the first time the concept has been used.

I did archaeological work in one of the valleys for this one in the late '70s: https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station

http://www.youtube.com/watch?v=o7KQGIEeiJ8&feature=youtu.be
You mean besides our foremost geologist, ND news reporter and fierce defender of freedom and life, you are also an archaeologist?
@Smokin Joe

Did the archeology dream give way to the reality of making a living as a geo?  Or more likely, the '79 run-up in o/g prices dangle dollar signs above your head?
No punishment, in my opinion, is too great, for the man who can build his greatness upon his country's ruin~  George Washington

Online Smokin Joe

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #27 on: March 24, 2017, 03:26:51 am »
You mean besides our foremost geologist, ND news reporter and fierce defender of freedom and life, you are also an archaeologist?
@Smokin Joe

Did the archeology dream give way to the reality of making a living as a geo?  Or more likely, the '79 run-up in o/g prices dangle dollar signs above your head?
I found my first arrowhead at five and grew up reading National Geographics from back into the 1800s. As a kid, I had a pretty good handle where on the farm I could find arrowheads, pottery fragments, and the like, and even found a few odds and ends dating back to the early 1700s, bottles of Civil War vintage and the like. I even got a metal detector with my haying money and told my mother I was going out to find the family treasure. (She said, "Son, you have it in your hand.") I had a lot of fun with that thing, but never found anything of note with it.

Archaeology remains an interest and something I love to do, but it was a summer job and the money wasn't the best, and besides, I was on my way to a Master's Degree in Uranium Geochemistry (or so I thought), full ride.

After a year of Grad School, my car having been hit five times--three times when parked (and finally totaled out) in eight months,  my bankroll wasn't much of a roll, and I decided to go to work for a year and consider my options.  I hired on with a mudlogging outfit, to start at the end of the school year, and two weeks later Three Mile Island happened. Well, that was the end of the Uranium dream, and I was already in the oil patch...I drove what was left of that car across the state (ground the treads off a set of nearly new bias ply tires doing so--the frame was bent that bad) with the side closed up with duct tape, plastic, and cardboard, and most of my stuff tucked into corners or tied to the roof.

Thank God the company had company pickups...
How God must weep at humans' folly! Stand fast! God knows what he is doing!
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Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive. It would be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience.

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Offline Free Vulcan

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #28 on: March 24, 2017, 04:57:36 am »
Fascinating. They can pump the water uphill gradually in times of demand slack, then let it roll at peak demand. Neat idea.
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Offline Joe Wooten

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #29 on: March 24, 2017, 12:16:19 pm »
Absolutely.  Some have claims of ~80% efficiency.

http://energystorage.org/energy-storage/technologies/pumped-hydroelectric-storage

Wind and Solar are not dispatchable; you have to take the power when it comes, not necessarily when it is needed.  Base load power plants are most efficient fully loaded running 24/7. 

Combining those with pump storage or other energy storage systems allows more peak load to be serviced on demand.

I can believe that. The average efficiency of large electrical pumps running at optimum load is about 82%. The average efficiency of a hydro turbine generator is about 95%. That gets a combined system efficiency of about 78%.

Offline IsailedawayfromFR

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #30 on: March 24, 2017, 04:28:29 pm »
I can believe that. The average efficiency of large electrical pumps running at optimum load is about 82%. The average efficiency of a hydro turbine generator is about 95%. That gets a combined system efficiency of about 78%.
As a comparison, any statistics on the % efficiency of say, a car battery?  The amount of energy to charge, the loss during a reasonable storage time, and the resultant strength of output of energy when used?
No punishment, in my opinion, is too great, for the man who can build his greatness upon his country's ruin~  George Washington

Online Smokin Joe

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #31 on: March 24, 2017, 04:37:32 pm »
As a comparison, any statistics on the % efficiency of say, a car battery?  The amount of energy to charge, the loss during a reasonable storage time, and the resultant strength of output of energy when used?
You might want to add in lifespan, too. That facility in Virginia has been going since the early '80s. The longest life I ever got out of a car battery was 12 years out of an Interstate, and that was exceptional (especially in this climate).
How God must weep at humans' folly! Stand fast! God knows what he is doing!
Seventeen Techniques for Truth Suppression

Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive. It would be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience.

C S Lewis

Offline thackney

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #32 on: March 24, 2017, 05:14:49 pm »
As a comparison, any statistics on the % efficiency of say, a car battery?  The amount of energy to charge, the loss during a reasonable storage time, and the resultant strength of output of energy when used?

Be sure to include chargers, inverters and any transformers used in the comparison.  AC in to AC out.

I'll look later when I can.
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Offline IsailedawayfromFR

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #33 on: March 24, 2017, 05:16:55 pm »
Thanks,  I bet it is a lot less than 80%.
No punishment, in my opinion, is too great, for the man who can build his greatness upon his country's ruin~  George Washington

Offline Joe Wooten

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #34 on: March 24, 2017, 05:22:48 pm »
As a comparison, any statistics on the % efficiency of say, a car battery?  The amount of energy to charge, the loss during a reasonable storage time, and the resultant strength of output of energy when used?

About 85% is assumed for a lead-acid battery, but you cannot do very many deep discharges before you ruin it, and that efficiency is very dependent on air temperature. Also, it would take a LOT of batteries to equal the output of a moderate sized pumped hydro unit. A battery optimized for power purposes will store about 2 KWh of electricity. A moderate pumped hydro station will run about 350 MWe, probably can operate at nameplate for about 6-10 hours, call it 8 hours to anally extract a number, making the total production on a typical day about 2800 MWh. You would need 175,000 batteries to store the equivalent amount of energy and last about 300-500 cycles before being replaced, assume 400, essentially replacing every 2 years or so. Assuming $500/battery, that's $87,500,000 to be spent every two years, not counting maintenance costs. A 350 MW hydro station  probably will cost $1,000,000,000 to build and will last 60 years before any major equipment has to be replaced. In that same time you would replace the batteries 30 times for a cost of $2,625,000,000, which does not include the original cost.

Also, the hydro turbine can make 60Hz AC electricity directly, the batteries will need a rectifier to convert DC to AC, which will add another efficiency penalty, causing the battery installation to be even bigger to overcome this problem. Batteries as they exist now and in the near future are not the answer, and probably never will be.
« Last Edit: March 24, 2017, 05:23:11 pm by Joe Wooten »

Offline IsailedawayfromFR

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #35 on: March 24, 2017, 05:36:16 pm »
About 85% is assumed for a lead-acid battery, but you cannot do very many deep discharges before you ruin it, and that efficiency is very dependent on air temperature. Also, it would take a LOT of batteries to equal the output of a moderate sized pumped hydro unit. A battery optimized for power purposes will store about 2 KWh of electricity. A moderate pumped hydro station will run about 350 MWe, probably can operate at nameplate for about 6-10 hours, call it 8 hours to anally extract a number, making the total production on a typical day about 2800 MWh. You would need 175,000 batteries to store the equivalent amount of energy and last about 300-500 cycles before being replaced, assume 400, essentially replacing every 2 years or so. Assuming $500/battery, that's $87,500,000 to be spent every two years, not counting maintenance costs. A 350 MW hydro station  probably will cost $1,000,000,000 to build and will last 60 years before any major equipment has to be replaced. In that same time you would replace the batteries 30 times for a cost of $2,625,000,000, which does not include the original cost.

Also, the hydro turbine can make 60Hz AC electricity directly, the batteries will need a rectifier to convert DC to AC, which will add another efficiency penalty, causing the battery installation to be even bigger to overcome this problem. Batteries as they exist now and in the near future are not the answer, and probably never will be.
Thanks, was not trying to replace the suggested water impoundment with a bunch of batteries, just trying to see how efficient an expected 80% efficiency of the water scheme is to something we all use like a car battery.

Seems they are similar in efficiency, save for some of the issues related to chargers, life of battery, etc.
No punishment, in my opinion, is too great, for the man who can build his greatness upon his country's ruin~  George Washington

Offline Joe Wooten

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #36 on: March 24, 2017, 05:42:28 pm »
Thanks, was not trying to replace the suggested water impoundment with a bunch of batteries, just trying to see how efficient an expected 80% efficiency of the water scheme is to something we all use like a car battery.

Seems they are similar in efficiency, save for some of the issues related to chargers, life of battery, etc.

Yep....   ^-^
My inner engineer just cannot let go a chance to pontificate......

Offline IsailedawayfromFR

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #37 on: March 24, 2017, 08:09:23 pm »
Yep....   ^-^
My inner engineer just cannot let go a chance to pontificate......
No, you did quite well revealing just how impressive the amount of stored energy exists in this proposed setup.
No punishment, in my opinion, is too great, for the man who can build his greatness upon his country's ruin~  George Washington

Offline thackney

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Re: Virginia to Utilize Old Coal Mines for Hydropower
« Reply #38 on: March 27, 2017, 01:41:06 pm »
As a comparison, any statistics on the % efficiency of say, a car battery?  The amount of energy to charge, the loss during a reasonable storage time, and the resultant strength of output of energy when used?

This is a relatively new utility sized energy storage system using batteries.  It is higher than I expected, but not high enough to be economic.

Quote
The economics of battery participation in energy markets are driven by the differentials between electricity prices at which the battery is charged versus those at which the battery is discharged.  The project observed that these price differentials were not large enough on a consistent basis to offset the inherent round trip efficiency of the BESSs, which averaged about 75 percent.

https://www.pge.com/pge_global/common/pdfs/about-pge/environment/what-we-are-doing/electric-program-investment-charge/PGE-EPIC-Project-1.01.pdf
Page 2

BESSs =  Battery Energy Storage Systems

PG&E started with two of these BESSs.

Vaca-Dixon BESS = 2 MW / 14 MWh NAS Battery

Yerba Buena BESS = 4 MW / 28 MWh NAS Battery

A lot of times they reached 80% efficiency.  But storage time can have a great impact on that.

http://www.energy.ca.gov/research/notices/2014-12-01_workshop/presentations/Jon_Eric_Thalman_Robert_Shainker_Pacific_Gas__and__Electric_and_EPRI.pdf
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