Want to conserve water? Turn off your lights.
An article this past Sunday in the AJC (thanks to Stephen for the link) goes into detail about how much water is used to generate electricity.
I think this sums it up best (bold emphasis mine):
Government agencies, however, have calculated that thermoelectric plants with once-through cooling use an average of 25 gallons of water to produce one kilowatt hour of power.
The average Georgia household burns 1,100 kilowatt hours of electricity a month. That translates to about 27,000 gallons of water.
By comparison, a family of four goes through about 9,000 gallons a month for household uses such as washing clothes, flushing toilets and showering.
It sounds like we should be bragging about how much we’ve reduced our electric usage each month, not just our water. However, I’ve not heard anything from our leaders about reducing electricity to help with the drought — but I think we should.
Sara Barczak, who was quoted in that AJC article, helped write this PDF titled “Climate change implications for Georgia’s water resources and energy future”, from the 2007 Georgia Water Resources Conference back in March of this year. It’s a long document, but well worth reading.
November 20th, 2007 at 5:19 pm
Remarkable that we’re only learning of this now. Governor Perdue “scoffed” at the idea in the article, which is quite depressing. Where is the leadership in Georgia?
November 20th, 2007 at 8:52 pm
Yes I read that article yesterday, but this situation is not just about saving electricity. The main reason water is being released from Lake Lanier is to cool power plant generators and to keep nuclear power rods from melting down. Each of the plants on Chattahoochee river needs at least 1 billion gallons or more of water daily to operate. Once the lakes on the river are empty, then all the power plants would be forced to shut down
November 21st, 2007 at 6:26 am
I suspected this was the case. Were the mussels a “red herring” or what? What this means is that the water shortage has a hard bottom line; not a soft bottom line where a rational decision could be made to sacrifice mussels for the regional economy.
Every elected official since 1981 who has not been on record to either restrict growth or create water resources should be held accountable. All I ever heard from them was how they were trying to “bring business to Georgia,” etc. They had not right. Promoting growth under the circumstances was fraud.
November 21st, 2007 at 7:51 am
This is from Sara Barczak’s report:
“To put this into perspective, with average per capita daily water use in Georgia at 75 gallons from surface and ground water, more water will be lost as steam from the possible four reactors at Plant Vogtle than is used by all residents (2005 census) of Atlanta (470,688), Augusta (190,782) and Savannah (128,453) combined (Fanning 2003).”
Apparently Georgia doesn’t even factor in the loss to steam for power plants once the steam reaches the river at a higher temp?
That’s why it’s hard to find any hard numbers with Purdue’s “shell game”.
I’ve been skeptical about solar and wind but not anymore. they can compete with coal and nuclear, don’t use water, and it cost nothing to replace a solar cell, as opposed to a nuclear plant in which we don’t even know how much it cost to decommission.
Unfortunately we are still building coal plants as well as nuclear.
Thanks for the article! I certainly learned a lot!
November 21st, 2007 at 8:49 am
Years I go, I toured the core of Vogtle unit II before it went on-line. Pretty damn cool.
Anyway, at that time, the cooling towers ran 50,000 GPM each and turn 25,000 gallons into steam. The water returned to the river was 5 degrees higher than the inlet temperatures.
This was a big deal, because some of the older plants were claimed to be responsible for damaging the local ecosystems due to high temperature water being discharged. As a result, it was a big deal that the water was only 5 degrees warmer.
Bear in mind this was from over 20 years ago.
And as far as I’m concerned, nuclear is the way to go. It’s not ideal, but it beats the heck out of coal and gas fired power generation. Hydro would be nice, but the reality is that it’s far more subject to variation than nuclear.
–jc
November 21st, 2007 at 9:10 am
Gov. Perdue is failing to tell the citizenry of Georgia that along with Lake Lanier going bone dry the coal-fired & nuclear power plants on Chattahoochee River are going to go offline without water. This means massive freshwater shortage for Atlanta, but also blackouts of electricity as well. This next summer everything hits the fan big-time.
November 21st, 2007 at 9:53 am
To the best of my knowledge, there is only one nuclear plant on the Chattahoochee, and that’s the Farley plant in Alabama.
Anyone have a complete list of power plants on the Chattahoochee, including coal, gas, hydro, and nuclear?
–jc
November 21st, 2007 at 10:35 am
This is a clear case of exceeding the limits of what a river basin can sustain during a drought.
The problem is when states like Georgia and North Carolina (possibly Alabama) exagerate the capacity of a river basin.
They will exagerate the minimum flow rate to justify their consumption level, then when the drought hits want to cut that back. And the other states, people, and wildlife gets left with no water.
It’s also against federal law.
That’s why it’s important for states to recognize the limits of river basins during droughts.
November 21st, 2007 at 1:27 pm
I think the criticism of once-through cooling in the article is a quite a bit off.
It’s important to note that in a once-through cooling system, no water actually leaves the stack unless there is an air scrubber installed (only necessary in coal plants burning high-sulfur coal) and the water that runs through the turbine is in a closed loop so the only opportunity for water use is through the boiler water cooling system. The article correctly points out that the water leaves this system somewhat hotter than the water that came in.
First, let’s take a look at the effect of this on evaporation:
Assume the water leaving the plant is 20 degrees Fahrenheit warmer (about 7 degrees Celsius). This corresponds to, using 4.18 J/gC as the heat capacity of water, 28 Joules per gram of water leaving the plant.
Compare this to 2260 J/g of water necessary to actually vaporize it.
So basically, even if you believed that 100% of the energy in the water leaving the plant was going towards vaporizing the water instead of simply mixing with the lake water (this situation would violate the second law of thermodynamics in a very big way), that would mean that only 1% of the water that flows through the plant actually evaporates. The reality is much, much less as there is significant mixing with the rest of the river water.
Ok, well, maybe you don’t believe that for some reason. Let’s instead assume that the government’s estimate of 25 gallons per kW hour is correct.
Then a modestly-sized coal station producing 300 MW produces 300,000 kWh of power at peak capacity. Suppose further that it really is only running at 100 MW average per day, that gives us 2,400,000 kWh of power a day, for 60 million gallons of water per day… for a medium sized coal plant.
If you believe that 60 million gallons of water per day are evaporating from a coal plant with a once-through cooling system, I have a bridge in New York to sell you. That would be a violation of conservation of energy. More like, “60 million gallons of water *pass through* the plant and are returned to the river cleaner than when it entered, where less than one percent of that evaporates that wouldn’t have evaporated otherwise.” Further, fish love this water and will congregate near the outflow from the plant–cops have been called in my area when fishermen fight over this choice spot for fishing.
Moving away from once-through water cooling is going to be expensive, require more plants running at lower capacity, and altogether unnecessary. The Electric Power Research Institute wants to play off your fears to sell you new power plants and expensive new technology with only marginal benefits over what exists.
Someone tell the AJC that this is very bad–they have grossly overblown the effects of power use on the water crisis, and that misinformation is just as bad as wasting water.
~Ben
November 22nd, 2007 at 6:58 am
Thank you, Ben. You should put this in a letter to the editor of AJC.
I suspected that the priority of the AJC in reporting on the water shortage would ultimately be its usual mantra of anti-business, anti-nuclear, pro-environmentalism. They will sieze on public fears to promote their usual agenda which was a component of how we got in this mess to begin with.
November 22nd, 2007 at 8:46 am
So what we are doing is establishing a lower minimum flow rate during a time of drought.
Then you base your consumption on that.
November 26th, 2007 at 12:43 pm
I’m amazed the average family uses 9,000 gallons of water per month! It’s so far out there for me… Last month my family of 3 used 300! We usually use 200, so I’m not sure what was different last month. We use low-flow shower heads, use the ’sniff’ test for our laundry (if it doesn’t look or smell we’ll re-wear it…except socks and underwear of course!), and we have a low-flow flapper on the main toilet (it doesn’t do a full-flush unless you hold the handle down) so we only have to use the water necessary to flush what’s there and not a whole tank. We are on town water and sewer.
We’re pretty good about electricity too: we only have laptop computers, are very good about turning off all of our florescent lights (we only have 3 incandescents in the whole house), we have powerstrips on all of our electronics and appliances (no stove or microwave clocks for us!), and we unplug all of those powerpacks used by the baby monitors and cellphones etc. when they are not being charged. We wound up using 137 kw last month, which is 4.5kw/day, higher than the summer (where we’re right about 4.0kw/day) because we use lights more in the fall… Using the fall daily average of 4.5kw/day, that comes out to 1642.5kw/year. The average US family uses a little over 10,500kw/year (from: http://urbanlegends.about.com/od/government/a/al_gore_energy.htm, scroll to the bottom…), almost 30kw/day. I can’t even think about that amount of usage!
I can just imagine if more people were half as efficient we we are and our energy crisis/water crisis would be much smaller…
It’s not hard, we’re just thoughtful about being as gentle on Mother Earth as we can…
November 28th, 2007 at 1:13 pm
300 gallons for a family of three?
Really?
Post your efforts on the forums - they could be useful.
I can’t imagine that low a useage. My wife and I each drink about a gallon a day - that’s 60 in a month. If you figure you have to flush the toilet at least twice a day that’s 90 gallons a month. If we shared a shower each day that’d be maybe 5 gallons of water a day (and that’s a navy shower) - 150 more a month. That’s 300 right there before cooking, cleaning, and laundry. For a family of two.
I’m astounded.
December 12th, 2007 at 3:03 pm
[...] we’ve mentioned before, power plants are massive users of water. Because of that, saving energy in your house can mean [...]