"Pump Back Reservoirs" - Explanation as to why they are desirable

[MikeyL]

Someone, in a thread about Georgia Power's Lake Oconee, asked me a question about the lake level. Private enterprise lakes, as opposed to U.S.Corp of Engineer lakes, are able many times to have FIXES docks - as opposed to floating docks.

You can have FIXED docks when you have a relatively SAME water level thruout the year. Other wise you must have floating docks.

One of the main reasons for FIXED docks is that the lake was designed for this from the beginning, AND because many times the lake is/was designed as a "pump back reservoir." So I thought: Hey ! Maybe some other people would enjoy learning a little about how all of this works. Sincerely hope you enjoy reading this. Best Wishes to all, Mikey Lulejian

Does the lake maintain its level all year ?

Yup ........ Sure does. It was the last lake Georgia Power made in, back in 1979. And they decided to do it "right" (added as a sidenote, when compared to some of their older existing Georgia lakes they had previously created).

It is designed as a "Pump-Back Reservoir." What that means is simply this:
Our water fluctuation rate is less than 18" a day. Normally a LOT LESS than that ... maybe 8-9 inches or less (daily). And we normally stay "FULL POOL" all year long. There have been a few years where due to severe droughts Oconee has gone down 4-5+ feet (and that's a lot for this lake), but thanks to the late fall normal rainfall, we would always be full by New Years.

So this also means we all have FIXED docks, which is why it's such a great bass fishing lake. GREAT fishing, for BASS (Largemouth, stripers, hybrids), and crappie, and catfish, as part of their overall plan.

Lakes Lanier and Allatoona and Hartwell, US Corp of Engineers' lakes), due to the SIGNIFICANT lake level changes, all have floating docks.

By the way: Additional sidebar: Georgia Power OWNS all of their lakes' shorelines. They tell you WHAT KIND of dock you can have (our is called a "max docks, largest they allow), WHERE it must be located on the lot, what the set-back must be for the house structure, what trees you CANNOT cut, and more. And then we have a renewing 15 year lease, which costs us $100 a year for Ga Power to "maintain the shoreline." Which explains why lakes like Lake Oconee, Lake Sinclair, Lake Wedowee (Alabama Power) look so very nice !

How this PUMP-BACK RESERVOIR works is this: First, you gotta know "power" does NOT have the same "value" at all times of the day. It's worth the MOST starting about 5 pm, when you get home, turn on the lights & the AC or heat, start the ovens, turn on the TV's, etc.

Now, however ........... at 9 am the next morning, when everyone has left for work, school, shopping, whatever, and few people are using any power, POWER has a lot less value.

Remember those hydro power generators @ and in Wallace Dam, connecting Lakes Oconee and Sinclair ?

Well, they take some "excess power" and feed it back INTO those same generators, and they then in turn automatically become PUMPS !

And so, they take water FROM Lake Sinclair, and pump it back into Lake Oconee !

Now, also, an added benefit of doing this is that this water flow causes the shad to move .......... The shad move ==> the bass move ... and Voila ! Great fishing ! The shad move TWICE ...... both when they are generating power, and then when they are putting water back into Oconee.

Now a little extra Bonus (!@!!) information thanks to Uncle Mikey:

I call this "God's LAW OF WATER"> And this is not a joke. The Good Lord said you CANNOT simply dam up a body of flowing water and decide to keep it all for yourself. HIS plan called for the water to flow and feed and suffice other areas of his creation. And none of this is a joke. Ya just cannot do that ! You must allow for water flow to "continue" after you have constructed a dam. SO, If Ga Power (part of the Southern Company, like Alabama Power - Lake Wedowee - where Wedowee Marine is located, and other operating Southern Company companies) decides they wanna make a little extra power by Hydro from Lake Oconee ... and if they take out say 100 gallons, they CANNOT later "put back in" 100 gallons. It must be less than what they took out. So the water continues to flow downstream.

We don't run into problems like Lake Lanier where a body of water is trying to fulfill an ever-growing Metro Atlanta population. While we may have 1/10th the quantity of water of say Lanier (or less) since we are a shallow lake (Lanier is VERY deep, being in the foothills/mountains of N.E Georgia), we do have the added benefit of having 10 times + the water SUPPLY coming into Oconee, from the Oconee and Appalachee Rivers (and Richland Creek).

Well, this is a little long, but thought some might be interested in this diatribe. If I can answer more, please ask and I'll try.
Many Best Wishes your way, Mikey Lulejian - Lake Oconee, GA

 

[Evildwarf]

Uncle Mikey,
I have not been to Oconee or Sinclair but Wedowee is a very pretty lake, some good looking properties along the shoreline. Obviously a well managed body of water.
Someday I will have to pay you a visit on Oconee.
Thanks for the info, very interesting.

 

[MikeyL]

Uncle Mikey,
I have not been to Oconee or Sinclair but Wedowee is a very pretty lake, some good looking properties along the shoreline. Obviously a well managed body of water.
Someday I will have to pay you a visit on Oconee.
Thanks for the info, very interesting.

And Barbie & I sincerely hope you will ! Beautiful Lake .......... And we'ld so enjoy meeting you and hangin' out !
Sincere Blessed Wishes your way ! - Mikey Lulejian - Lake Oconee, GA

 

[Jim Robeson]

@MikeyL ... thanks for sharing!! Hopefully one of these days we can get to one of those beautiful lakes. Our area lakes are also managed by the Corp. And they are quick to tell you that these lakes were created for flood control, NOT recreation. Here recently they have had a change of heart since it was brought to their attention that over 200 million dollars are spent in and around the lake area...for recreation! They have done a better job this year maintaining the lake levels so us folks with floating docks don't have to move as much. Would be nice to be on a lake like yours that you didn't have to worry as much as we do.

Thanks again for the info!!

 

[Big Shasta]

Excellent info, but wow, that blue hurts to try and read.

 

[Wayloncle]

Excellent info, but wow, that blue hurts to try and read.

Sometimes I wish I could make my phone black and white

 

[Andy S]

@MikeyL nice write up. Here is some more information about Pump Back or Pump Storage, same thing just called different. This additional information might be more than most people want to know but I thought someone might find it interesting.

I work for a utility here in South Carolina and we have a lake that is used for Pump Back but we call it Pump Storage. Our Pump Storage lake was made to supply cooling water to a nuclear power plant and for Pump Storage. The lake level swings about 4 feet each day and has a maximum swing of 5 feet, more than a 5 foot swing will impact the cooling for the nuclear plant which is not a good thing. There is a river adjacent to the lake which is about 80' lower than the lake. When the Pump Storage is in the generating mode water flows from the lake to the river (80' drop) and when in the pumping mode it pumps from the river back up the 80' into the lake. The lake is in a very rural part of the state and I don't believe there are many people that actually live on the lake plus due to the level fluctuations docks are not permitted. Also, when the lake was built they did not clean out all the trees that are now under water which makes for good fishing but not for pleasure boating.

Most hydro power has no fuel cost, mother nature provides the fuel (rain, flow from upstream lakes and/or rivers) but with Pump Storage the cost is not free. As Mike explained the power system takes excess power (coal, nuclear, nature gas, etc generation) to feed the Pump Storage generators which turns them into motors and pumps water up the hill. For our utility we Pump at night, non-winter months midnight to 6 am and winter months pump from 1 am to 4 am and 1 pm to 4 pm, for our system these are the lowest system loads. The double benefit of pumping at the lowest load is the availability of cheap excess power and it keeps power plants at higher outputs which is were they are most efficient and prefer to run. Actually most utilities that can have Pump Storage lakes due because of these multiply benefits.

Now for the cost of Pump Storage power. Most power used for pump storage ranges in cost from the low teen (nuclear) to high 20's to low 30's (coal and natural gas which can very greatly depending on the time of year and weather conditions), we will use $20 for an average cost of pumping fuel. For every MW (megawatt) of power used to pump water back up the hill later when you start generating you only get about 70% of the power back, e.g. if you use 500 MW of power to pump with you will only get 350 MW of power when you generate. The reason for lost power is due to the work needed to pump water up a hill, the generator/motor electrical losses. Therefore in our example after pumping water back into the lake the cost to generate from the Pump Storage is $28.57 ( $20 pumping power / 70%).

To put this cost into perspective. Most people for their residence pay about 9 to 12 cents per KW (kilo watt) of power, if you use 1000 KW's per month your bill will be $90 to $120. Also for the non-metric efficient readers, 1 MW = 1000 KW. Therefore, of your electric bill about 1/3 is the cost of fuel to generate the power you use, the other 2/3's is to pay for transmission/distribution lines, construction cost, administrative cost, etc.

Below is a picture of our Pump Storage facility with nuclear plant in the background. The large tubes carry the water between the lake and the river and are large enough for a full size tractor trailer rig to drive through. Each tube supplies water to 2 generators located at the river level.

 

[MikeyL]

WOW !!!!!!!! Thanks so much for all of this additional FACTUAL information.
I enjoyed learning more about this, myself.
Does your work function for Lake Murray in S.C. ? BTW, a GORGEOUS body of water !!!!!!!!
Again, so many thanks for this important addition ! And Sincere Best Wishes your way - Mikey Lulejian

PS - As a sidenote ........ The Southern Company (from a control command center in Birmingham, AL) NORMALLY "draws" water from Oconee in the afternoon, and puts it back the next morning.
Not always, but normally.

 

[Andy S]

WOW !!!!!!!! Thanks so much for all of this additional FACTUAL information.
I enjoyed learning more about this, myself.
Does your work function for Lake Murray in S.C. ? BTW, a GORGEOUS body of water !!!!!!!!
Again, so many thanks for this important addition ! And Sincere Best Wishes your way - Mikey Lulejian

PS - As a sidenote ........ The Southern Company (from a control command center in Birmingham, AL) NORMALLY "draws" water from Oconee in the afternoon, and puts it back the next morning.
Not always, but normally.

Thanks Mike! My job for the utility is buying and selling electricity between utilities and marketing company with Southern Company being one of our biggest and best customers/suppliers.

The utility I work for also maintains Lake Murray but that lake is traditional hydro facility with only seasonal fluctuations, it is not a Pump Storage lake. Lake Murray's primarily water supply is from the Saluda River which comes from Lake Greenwood which is now operated by the City of Greenwood (previously owned/operated by Duke Power). Lake Murray level peaks at 358' from about May to Sept and then from Sept to May it will be allowed to come down to 353' before returning to 358' and every 5 years the level will drop 10' to promote lake health, lake weed control, and shoreline maintenance.

 

[Big Shasta]

A buddy of mine/former coworker now works for Southern Company in Birmingham. We catch up with him and his family on Lake Martin every summer when we go up for vacation, he has a lakehouse there. This summer he was schooling me on what goes on behind the scenes with buying and selling power like the stock exchange. Cool stuff.

 

[Andy S]

A buddy of mine/former coworker now works for Southern Company in Birmingham. We catch up with him and his family on Lake Martin every summer when we go up for vacation, he has a lakehouse there. This summer he was schooling me on what goes on behind the scenes with buying and selling power like the stock exchange. Cool stuff.

It use to be more exciting but with the recession of 2008, fracking of natural gas and energy conservation/efficiency the power trading has changed dramatically. The concept of moving electricity from place to place around the electric grid is still very interesting.

 

[Big Shasta]

It use to be more exciting but with the recession of 2008, fracking of natural gas and energy conservation/efficiency the power trading has changed dramatically. The concept of moving electricity from place to place around the electric grid is still very interesting.

Those are also some of the other things he was talking about ...excess nuclear generated power and how it's sold and how the decisions to throttle natural gas powered plants factor in. Very cool stuff.

 

[buckbuck]

We need more nukes.

 

[Andy S]

We need more nukes.

There are 4 brand new ones currently being built, 2 in South Carolina by the company I work for and 2 by Southern Company just west of Augusta, GA. Just like investing, power production needs to be a balanced approach this will help ensure the reliability of the electric grid.