Warming climate likely to have 'minor' impact on power plant output


Mountaineer Power Plant - Image from Panaramio by Mcgiver1
Mountaineer Power Plant – Image from Panaramio by Mcgiver1

Study assessed rising temperatures’ effect on power plant cooling efficiency and energy output

DURHAM, N.C. — Future climate warming will likely cause only minor cuts in energy output at most U.S. coal- or gas-fired power plants, a new Duke University study finds.

The study — the first of its kind based on real-world data — rebuts recent modeling-based studies that warn rising temperatures will significantly lower the efficiency of power plants’ cooling systems, thereby reducing plants’ energy output. Those studies estimated that plant efficiencies could drop by as much as 1.3 percent for each 1 degree Celsius of climate warming.

“Our data suggest that drops in efficiency at plants with open-loop, or once-through, cooling systems will be a full order of magnitude smaller than this,” said Candise L. Henry, a doctoral student at Duke’s Nicholas School of the Environment. “Reductions at plants with wet-circulation, or closed-loop, systems — which can be identified by their cooling towers — may be even smaller.”

“In large part, this is because plant operators are already constantly adjusting operations to optimize plant performance under changing environmental conditions,” she said. “That’s a key consideration the past studies overlooked.”

The new findings do not, however, signal an all’s clear for the power industry, the Duke researchers cautioned.

“The impact of future droughts associated with global warming could still significantly affect plant operations and output by reducing the availability of water for cooling,” said Lincoln F. Pratson, Semans-Brown Professor of Earth and Ocean Sciences at Duke.

Henry and Pratson published their findings this month in the peer-reviewed journalEnvironmental Science & Technology.

To conduct their study, they analyzed hourly temperature and humidity data recorded at National Climatic Data Center (NCDC) stations and U.S. Geological Survey river gauges near 39 U.S. coal- or natural-gas-fired power plants over a seven- to 14-year period. By correlating this data with the plants’ hourly heat input and energy output records, obtained through the EPA’s Air Markets Program Data website, they were able to extrapolate how much of each plant’s output was the result of daily and seasonal variations in temperature.

“These variations exceed estimates of the average future annual increase in warming under a moderate global warming scenario,” Henry noted, “so we could actually see — based on empirical evidence — how plants’ operations are affected by temperature changes much more dramatic than what is projected to occur.”

To ensure a representative sample, the study included both closed-loop and open-loop plants from the Northeast, Mid-Atlantic, Southeast, Midwest, Deep South, Great Plains and Rocky Mountain regions. Output capacities ranged from less than 500 megawatts up to 3,000 megawatts.

The cooling efficiency and energy output of every plant — regardless of location, generating capacity or fuel type — was found to be more resilient to climate warming than previous studies predicted.

Plants with closed-loop cooling systems were found to be particularly resilient.

“This provides additional rationale for section 316b of the EPA’s Clean Water Act, which requires most electric generators to install closed-loop recirculating systems,” said Pratson.

“The EPA enacted section 316b to protect fish, shellfish and other aquatic animals from being pulled into, and harmed or killed in power plants’ cooling water-intake structures,” he noted. “Our study shows it could also provide the added benefit of helping protect the power plants themselves from the impact of climate warming.”


The paper:

“Effects of Environmental Temperature change on the Efficiency of Coal- and Natural-Gas-Fired Power Plants,” Candise L. Henry, Lincoln F. Pratson, Environmental Science & Technology, August 1, 2016; DOI: 10.1021/acs.est.6b01503

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August 15, 2016 12:31 pm

Captain obvious credentials granted

Jeff Norman
Reply to  Resourceguy
August 15, 2016 1:40 pm

Okay. That’s funny.
As someone who used to do turbine and boiler efficiency testing, yes it should be obvious that the annualized impact would be negligible.

Bryan A
Reply to  Jeff Norman
August 15, 2016 2:20 pm

Though their numbers doo pan out. 1 – 1.3 = 75 – 99
An increase of 75C would definitely equate to an efficiency drop of 99% (100%)
there wouldn’t be anyone left to run the plan(e)t

Reply to  Resourceguy
August 15, 2016 4:51 pm

yeah, i think around 30 seconds with a slide rule should be enough..

Reply to  Leo Smith
August 15, 2016 6:00 pm

I’d call it 15 seconds… and you only need a 6 inch slide rule for enough precision…
Then again, I still carry a 3 inch circular sliderule in my travel bag for milage and time calcs… so I’m in practice 🙂

August 15, 2016 12:40 pm

Future climate warming will likely cause only minor cuts in energy…
Well good grief…..when future climate warming will only be minor in the first place

August 15, 2016 12:40 pm

My 35 year professional career was as an ME in power generation, all types, all over the US, O&M at the plants & design with EPCs.
What a load of baloney. Climate change will not do near as much damage (i.e. none) to power plant efficiencies as PUC imposed fuel cost adjustments that pass the cost of inefficiencies through to the rate payer and semi-qualified, indifferent, O&M understaffing thanks to clueless, pointy haired management.

Jeff Norman
Reply to  nickreality65
August 15, 2016 1:48 pm

That’s not strictly true. Marginally sized air preheaters (or compressors in the case of combustion turbines) can result in de-rates on the hottest of days. If your greenhouse warming takes place in the winter, no problem. If you get one or two more hottest days then you could be looking at a potential 10% de-rate about 0.3% of the time.

Tom Johnson
Reply to  Jeff Norman
August 15, 2016 4:28 pm

10 percent of 0.3 percent equals 0.03 percent overall efficiency loss. That’s a whole lot less than 1.3 percent per degree C.

Reply to  Jeff Norman
August 15, 2016 7:30 pm

CT inlet cooling can fix that. Ambient air doesn’t impact Rankine’s as much. Just add a little more fan.

Reply to  Jeff Norman
August 16, 2016 8:53 am

And how many “marginally sized” APHs are there? You have no idea, I know I don’t.

Joel Snider
August 15, 2016 12:41 pm

I think ‘minor impact’ pretty much describes the whole phenomenon. Only been saying that for twenty years now.

August 15, 2016 12:41 pm

My objections to the “science” behind mankind driven climate change:
The greenhouse effect theory, i.e. upwelling/down welling/”back” radiation violates conservation of energy and thermodynamic laws. Yes, it really does! Not that it matters because the theory actually does not do anything, i.e. no net change in radiative balance at the ToA, per NASA 100 km.
The notion that the earth is 33 C warmer with an atmosphere than without is incorrect. The conditions postulated for the “no atmosphere” scenario are quite obviously with an atmosphere. The true explanation for the prevailing surface temperature, heat transfer’s most fundamental equation Q = U * A * dT, is ignored.
The Stephan Boltzmann ideal black body equation is incorrectly applied by ignoring the theory’s limitations and conditions, e.g. a surface, no conduction/convection, i.e. a vacuum, emissivity, gas density, tropospheric temperatures, etc.
The eccentricity of the earth’s orbit causes a TSI fluctuation, apehelion to perihelion, 10 times greater than the atmospheric heating due to CO2. Natural variations such as eccentricity, albedo, water vapor, vegetation, etc. are orders of magnitude more influential over the climate than GHGs/CO2.
Nick Schroeder, BSME, PE
(I might be unqualified to offer an opinion since I’m not a food editor, unemployed standup comic, massage therapist, nematologist, or fresh out of journalism school.)

Reply to  nickreality65
August 15, 2016 1:50 pm

Ha, a good one
Yes you would not be listened to in this Administration, knowledge of Thermodynamics is un-welcome

Bruce Cobb
August 15, 2016 12:45 pm

Sharknadoes will also probably have a minor effect. Unless of course, sharks get caught in those cooling towers. Then all bets are off.

August 15, 2016 12:56 pm

Just how bad were those recent model-based studies, I wonder.

Rob Morrow
August 15, 2016 1:06 pm

The study — the first of its kind based on real-world data

Any second year mechanical engineering student knows the assertion above is a lie. Thermal efficiencies have certainly been measured in the real world and compared to theory. The only thing “first” about this study is the silly notion of studying the change of efficiency due to warmer temperatures caused by CAGW. The laws of thermodynamics don’t change for “man-made” heat. Heat is heat.

Reply to  Rob Morrow
August 15, 2016 2:29 pm

I’m a layman who has been following the CAGW debate for a number of years, becoming a skeptic over time and now a staunch “denier.”
What I would appreciate comment on is this chart —comment image — which I have yet to see refuted and which all but screams (1) that there is no correlation between global temperature and atmospheric CO2 and (2) that both are at historic lows, and dangerously so (especially CO2, since plants apparently die below 150 ppm).

Reply to  DeeDub
August 15, 2016 7:02 pm

“that there is no correlation between global temperature and atmospheric CO2”
That’s what that chart says to me, too.

August 15, 2016 1:17 pm

Well while they are at it, they should study the reduction in plant output due to warming temperatures lowering heating demand and thereby power plant output. Piggy back that with another study showing how global warming policies increases the cost of energy thereby depressing economies, and requiring less power plant output. And could go on, but won’t.
Nothing in the global climate/eco-system works independently in any way, especially a linear way. The climate is not a marble in a tunnel, whose behavior is easy to predict, it is more like releasing 100 cats into a room and watching dynamic chaos ensue.
Meanwhile 350.org is comparing global warming to WWII, which is insulting and stupid beyond belief. If only we could place those characters back in time in Berlin or London while the bombs fell.

August 15, 2016 1:26 pm

The “previous studies” that this Duke paper showed were wrong were not detailed in this article, nor in this WUWT briefing.
But I suspect that those previous studies projected a 6-10 degree temperature rise, with droughts across the US approximating the Sahara and Great Basin deserts and droughts. In the real world of a 1/2 to 1-1/2 degree C of projected AIR temperature measured warming. River water, like ocean water, does not go up when the air temperature rises.
So those plants on river-cooling see less load in winter if warming occurs. They may see an increase in air conditioning loads. but simply cleaning the condensers and tubing will make more of a difference than the potentially higher air temperature. Closed cycle cooled plants are similar.
Gas turbine plants reject their air through regenerative heat exchanger to make steam, then those are cooled just like the coal plants. A higher air temperature has a near-zero impact on efficiency for CT’s since they eject the burned fuel and exhaust gasses at 1350 – 1500 degrees out of the 4th stage exhaust blades. Coal burners use preheaters already to preheat the inbound burner air – so they will be able to burn even hotter air by those few 1/10’s of a degree.

August 15, 2016 1:43 pm

Seems to me that for some coal fired plants the reduction in power is going to be 100%

August 15, 2016 2:20 pm

I’m confused. Apparently Thermageddon will mean that, “The impact of future droughts associated with global warming could still significantly affect plant operations and output by reducing the availability of water for cooling,” But at the same time, Greenland will melt and sea-level will rise, meaning that the amount of water available will increase. What’s a body to think?

Bryan A
Reply to  Kevin Lohse
August 15, 2016 2:28 pm

One is Fresh Water (inside Drought affected areas) pulled from diminishing rivers and reservoirs and used for cooling while the other is Sea Water (bordering the Drought affected areas)

Reply to  Bryan A
August 15, 2016 9:29 pm

Sorry, should have writ /sarc. As the Israelis have proved, converting sea water into fresh water is a technical problem, not a resource scarcity. Improvements in desalinisation techniques can provide cheap fresh water which can then be piped to where it’s needed – or power plants can be re-sited to the new coastal areas, if Thermageddon actually happens. Furthermore, cooling water can be recycled using cooling reservoirs, cutting down the amount of water used. I’m pretty certain this is happening somewhere on the planet. In sum, if the worst happens there will be more water available, not less. The technology for getting water to the right place in the right forming sufficient quantity already exists, and the costs of adaptation would be both a lot less than the costs of prevention and more certain in their effectiveness.

Reply to  Bryan A
August 15, 2016 9:35 pm

“in the right form in sufficient quantity” Damned spellchecker!

Bryan A
Reply to  Bryan A
August 16, 2016 8:41 pm

Ayup, we are definitely more than capable of overcoming the obstacles posed by thermageddon when it comes to providing cooling infrastructure for power plants

Svend Ferdinandsen
August 15, 2016 2:35 pm

I guess most of Texas and other southeastern states are doing quite well and not lacking any water.

August 15, 2016 3:27 pm
Big Al
August 15, 2016 5:26 pm

In other areas of the world they use radiators (like in your car, but a tad bigger!) instead of taking the water from a river or lake and returning it. There are areas that don’t have the water flow to feed a power plant so they don’t use it. So what effect do these power plants have on the environment?

August 15, 2016 5:38 pm

Have Any comparable studies been performed with solar plants on the effect of a cloud passing in front of the sun.

Mike McMillan
August 15, 2016 5:52 pm

All that steam from the cooling tower is going straight up. I wonder if the wind turbines are turning?

August 15, 2016 7:09 pm

Why the two different types of towers at the powerplant?

Reply to  TA
August 16, 2016 8:58 am

One is a condenser cooling water tower, the fatter one, and the taller one is the “stack” that emits flue gas. In both cases the vapor you see is water vapor, the vapor in the flue gas is from the SO2 scrubber.

Reply to  oeman50
August 16, 2016 9:00 am

Just saw nick’s reply, which is accurate but may be more than TA was looking for.

Reply to  oeman50
August 16, 2016 6:01 pm

Thanks for that, oeman50. Why is the flue gas stack taller than the cooling tower?

Reply to  oeman50
August 16, 2016 10:26 pm

Typical wet towers use fans to pull/induce the air through the fill/water. When the generator gets big enough, in this case 1,300 MW, the circulating water heat load means a very large fan type tower, lots of horsepower. If the location’s ambient conditions are right a hyperbolic natural draft tower is an option. In this design the hot water heats the air and height and bouancy pull air through the fill/water and up the tall stack. Think hot air balloon.
The flue gas stack is tall for a similar reason. Flue gas enters the stack at about 200 to 350 F depending the design, fuel, AQCS, etc. The draft up the stack also reduces the work load on the ID fan. The stacks are usually around 500′ tall, but can be higher. Since the solution to pollution is dilution, release the flue gas up high where the winds can disperse it.
Palo Verde outside Phoenix could not use hyperbolics because of the desert conditions. Each of the 3 1,500 MW nukes has three wet towers w 15 fans each. You can see these in Google satellite images.
Many people assume a hyperbolic tower means nuclear, but it’s just an indication of a very large Rankine/steam generator.

Johann Wundersamer
August 15, 2016 8:07 pm

There’s cooling towers working from Scandinavia to Italy, from Portugal to kamtschatka.
US + Canada. Climate studies search for unseen problems. Unprecedented.

August 15, 2016 8:17 pm

“Why the two different types of towers at the power plant?”
A very brief (or not) tutorial.
In a Rankine or steam cycle the exhaust steam from the steam turbine must be condensed back into pure water to be pumped back through and heated by the boiler or HRSG. Half of the energy that enters the steam turbine leaves in the latent heat of condensation. This is the case w/ both typical fossil fueled, coal & NG, steam plants and the steam turbine of NG fossil fueled combined cycles.
A thermodynamic heat engine works between a high temperature source and a low temperature sink, the Carnot cycle being the ideal. The farther apart the source and sink the more energy available for conversion. So the colder the conditions in the condenser the lower the back pressure, the lower the sink temperature and the more efficient the cycle.
The water circulated through the condenser can come from a body of water, lake, ocean, river, manmade or natural. This is the preferred choice when available, low capital cost, coldest water.
Wet cooling towers are popular where lakes etc. are not feasible. This method operates just like an evaporative/swamp cooler. The water evaporating in the towers removes a tremendous amount of heat at the cost of significant water consumption. The cold water can approach within 10 F of the ambient wet bulb temperature. The makeup water source can be rivers, wells, even recovered non-pot. Simple, moderate cost.
Where water is not physically, fiscally, or politically available air cooled condensers are the choice. These are just like car radiators. Air on one side, condensing steam on the other. Air is a terrible heat transfer fluid. The ACCs condensing conditions approach the ambient dry bulb which can be substantially higher than the wet bulb. Depends on location, weather, etc. The amount of air needed requires huge fans that consume major amounts of house power. A double whammy to the lower efficiency. ACC foot prints and capital costs are much larger than comparable wet towers. The entire system in under vacuum which can be a maintenance head ache. Water chemistry can be problematic. Frequent starts/starts are bad.
For comparisons: Cherokee station near Denver, Comanche near Pueblo, Front Range near Colorado Springs.
I have a couple of papers on LinkedIn for those so inclined.

Reply to  nickreality65
August 15, 2016 10:28 pm

“at the cost of significant water consumption”
Not really! I have worked at a nuke plant serving a million homes in a semi-arid climate. Cooling tower makeup was diverted from an irrigation canal. If you compare the amount of water used for everything else to the amount to used to make electricity for everything else, water consumption is not significant.
The water is not actually consumed. When you burn coal it is consumed. Water is only a heat transfer mechanism. Water carries energy to the heat sink.

Reply to  Retired Kit P
August 16, 2016 6:23 am

Kit P
Water is evaporated into the surrounding atmosphere and the amount is well over 80% of a typical Rankine plant’s total water needs even at PVGS.

Reply to  nickreality65
August 16, 2016 6:03 pm

Thanks nick, I appreciate it.

August 15, 2016 10:04 pm

The whole concept is bogus. Climate change is a theory about a small change over a long period of time. Steam plants are designed to operate over a wide of weather conditions for the specific climate expected for the design life of the plant.

August 16, 2016 5:41 am

“Our data suggest that drops in efficiency at plants with open-loop, or once-through, cooling systems will be a full order of magnitude smaller than this,” said Candise L. Henry, a doctoral student at Duke’s Nicholas School of the Environment. “Reductions at plants with wet-circulation, or closed-loop, systems — which can be identified by their cooling towers — may be even smaller.”

There are hardly any open-loop plants left — almost all have been closed due to the EPA. And the EPA was restricting THOSE when river/lake temps got to a certain level. So the EPA was directly responsible for those “impacts”.

August 16, 2016 7:17 am

From Sourcewatch re the thread’s opening photo.
Mountaineer Plant is a coal-fired power station owned and operated by American Electric Power near New Haven, West Virginia.
In August 2009, AEP announced its application for funding from the U.S. Department of Energy’s Clean Coal Power Initiative. The company is asking for a $334 million grant to cover about half of the estimated costs of installing carbon capture and storage system at Mountaineer. According to the grant application, the system will capture at least 90 percent of the carbon dioxide from 235 MW of the plant’s 1,300 MW total capacity. The captured carbon dioxide, which is expected to be about 1.5 million metric tons per year, will be injected into geologic formations about 1.5 miles under ground. The company says it will have the system operational in 2015.[1]
In December 2009, AEP was awarded a $334 million grant from the Department of Energy for a commercial scale project that will capture carbon from its Mountaineer pilot plant.[2] The company notes that the “Mountaineer Plant CCS projects employ Alstom’s patented chilled ammonia process for post-combustion CO2 capture. The process uses ammonium carbonate to absorb CO2. The resulting ammonium bicarbonate is converted back to ammonium carbonate in a regenerator and is reused to repeat the process. The flue gas, cleaned of CO2, flows back to the stack and the captured CO2 is sent for storage.”[3]
On July 14, 2011, American Electric Power said it had decided to table plans to build the full-scale carbon-capture plant at Mountaineer, saying they did not believe state regulators would let the company recover its costs by charging customers, thus leaving it no “compelling regulatory or business reason to continue the program.”[4]
“We” demand CAGW action, but make someone else pay for it.

Reply to  nickreality65
August 16, 2016 11:07 am

..So did they have to give back the 2009 $334 million grant from the Department of Energy ?

August 16, 2016 9:03 am

“This provides additional rationale for section 316b of the EPA’s Clean Water Act, which requires most electric generators to install closed-loop recirculating systems,” said Pratson.
Not true. The 316(b) requires evaluation of closed circuit cooling for every site, but does not require it. It is still subject to a cost benefit analysis.

August 16, 2016 9:06 am

Do I recall most of the increase in the “average” world temperature is increased temperatures at night? If so, this will have little to no effect on power generation, since the cooling systems are sized for maximum daylight temperatures and loads are lower at night.

August 16, 2016 9:06 am

““The EPA enacted section 316b to protect fish, shellfish and other aquatic animals from being pulled into, and harmed or killed in power plants’ cooling water-intake structures,” he noted. ”
When are they going to protect the birds from the slaughter due to wind turbines from the replacement, unreliable generation? The noise impact on certain marine life is still being argued.
I spend a lot of time near the inflow/outflow of Forked River Oyster Creek Nuclear plant which uses the large Barnegat Bay for cooling water. Strange, there are all kinds of fish and marine life thriving in the outflow of the plant as evidenced by all year round fishing. Is it a marine plus or minus that fish and other marine life thrive in the warmer waters all year round and will not exist after the plant closure?. It will be shut down soon because the operator cannot afford to switch to mandated cooling towers, impacting the local economy, taxes, electricity prices, and jobs. No plan to replace the generation capacity with Natural gas, just offshore bird choppers all along and often visible from the beaches that will dramatically increase the cost of electricity. The Administration is already selling offshore leases which will likely impact the offshore aquatic population and restrict offshore fishing and Navigation since numerous vessels commercial and private travel the route along the coast impacted by the proposed wind turbines.
Meanwhile no offshore oil rigs permitted since they spoil the view.
When will this nonsense stop?

Reply to  Catcracking
August 16, 2016 6:13 pm

“When will this nonsense stop?”
Hopefully, before they build any more of those damn windmills.

Ed Zuiderwijk
August 17, 2016 9:33 am

Anyone with a modicum of knowledge about thermodynamics would have known that without need to spell it out.

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