Ocean pipes ‘not cool,’ would end up warming climate
![otec_mode_06_animation[1]](https://wattsupwiththat.files.wordpress.com/2015/03/otec_mode_06_animation1.gif)
Washington, D.C.–To combat global climate change caused by greenhouse gases, alternative energy sources and other types of environmental recourse actions are needed. There are a variety of proposals that involve using vertical ocean pipes to move seawater to the surface from the depths in order to reap different potential climate benefits. A new study from a group of Carnegie scientists determines that these types of pipes could actually increase global warming quite drastically. It is published in Environmental Research Letters.
One proposed strategy–called Ocean Thermal Energy Conversion, or OTEC–involves using the temperature difference between deeper and shallower water to power a heat engine and produce clean electricity. A second proposal is to move carbon from the upper ocean down into the deep, where it wouldn’t interact with the atmosphere. Another idea, and the focus of this particular study, proposes that ocean pipes could facilitate direct physical cooling of the surface ocean by replacing warm surface ocean waters with colder, deeper waters.
“Our prediction going into the study was that vertical ocean pipes would effectively cool the Earth and remain effective for many centuries,” said Ken Caldeira, one of the three co-authors.
The team, which also included lead author Lester Kwiatkowski as well as Katharine Ricke, configured a model to test this idea and what they found surprised them. The model mimicked the ocean-water movement of ocean pipes if they were applied globally reaching to a depth of about a kilometer (just over half a mile). The model simulated the motion created by an idealized version of ocean pipes, not specific pipes. As such the model does not include real spacing of pipes, nor does it calculate how much energy they would require.
Their simulations showed that while global temperatures could be cooled by ocean pipe systems in the short term, warming would actually start to increase just 50 years after the pipes go into use. Their model showed that vertical movement of ocean water resulted in a decrease of clouds over the ocean and a loss of sea-ice.
Colder air is denser than warm air. Because of this, the air over the ocean surface that has been cooled by water from the depths has a higher atmospheric pressure than the air over land. The cool air over the ocean sinks downward reducing cloud formation over the ocean. Since more of the planet is covered with water than land, this would result in less cloud cover overall, which means that more of the Sun’s rays are absorbed by Earth, rather than being reflected back into space by clouds.
Water mixing caused by ocean pipes would also bring sea ice into contact with warmer waters, resulting in melting. What’s more, this would further decrease the reflection of the Sun’s radiation, which bounces off ice as well as clouds.
After 60 years, the pipes would cause an increase in global temperature of up to 1.2 degrees Celsius (2.2degrees Fahrenheit). Over several centuries, the pipes put the Earth on a warming trend towards a temperature increase of 8.5 degrees Celsius (15.3 degrees Fahrenheit).
“I cannot envisage any scenario in which a large scale global implementation of ocean pipes would be advisable,” Kwiatkowski said. “In fact, our study shows it could exacerbate long-term warming and is therefore highly inadvisable at global scales.”
The authors do say, however, that ocean pipes might be useful on a small scale to help aerate ocean dead zones.
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A video abstract of the paper is available here:
The Carnegie Institution for Science is a private, nonprofit organization headquartered in Washington, D.C., with six research departments throughout the U.S. Since its founding in 1902, the Carnegie Institution has been a pioneering force in basic scientific research. Carnegie scientists are leaders in plant biology, developmental biology, astronomy, materials science, global ecology, and Earth and planetary science.
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There is currently a state run system at the island of Hawaii. Water is pumped from up to a depth of 3,000 ft.
http://nelha.hawaii.gov/about/
See this reference for a laundry list of OTEC problems (chemical effects for example):
http://crrc.unh.edu/sites/crrc.unh.edu/files/media/docs/Workshops/otec_2/a_primer_v3.pdf
Chemical Effects
o As previously mentioned the discharge water will contain corrosional and erosional
products, biocide from the heat exchangers, and possibly leaked working fluid. In
addition the platform will release biocides from the antifouling paint and there is always
the potential of a working fluid or biocide spill. These contaminants may act singularly
or in combination on exposed biota.
Direct toxicity to exposed organisms.
Biomagnification of toxins with toxicity to higher trophic level organisms including humans.
In the block diagram, the turbine is displayed backward. High pressure gas goes in the small end, and comes out the large end. As the turbine extracts power, the gas pressure drops and has to expand, so you need a bigger cross section as you work through each stage….
Nutters!!!
If the design does not give a useful net gain, will it do so if the cycle is reversed?
Geoff
It has been mentioned in comments already, in different ways, but what this tells me is:
If the oceans cool, there is a mechanism that starts warming them again (reduction in clouds). Ipso facto, if the oceans warm, there is a mechanism that cools them again (increase in clouds).
My take on this is that our climate is protected by at least one, and probably more, strongly negative feedback mechanisms. The fact that the climate has neither frozen completely or boiled away yet is a testament to that theory. Until that theory is disproved by empirical evidence (not models), I refuse to believe the climate is in any danger whatsoever from less than one tenth of one percent additional CO2.
This Global Warming. It’s just a free for all for hair brained schemes, con men and nut cases!
Whats up with the recent drop in the ENSO meter?
Houston to RobR,
Sorry about that. The ENSOmeter is currently out of action awaiting recalibration once certain adjustments are made to its reality reference device.
We are 97% confident that it will be back on line in due course making accurate forecasts that we can all take to the bank.
Houston sarcing off
It’s been windy around home this week (New Hampshire). The ENSO meter shook itself
off the wall peg I hang it on, if it doesn’t go back up next week, I’ll look for a replacement.
At best all it is doing is transferring heat from the surface to the deep ocean. It is impossible for it to cool the planet in this way, it is merely shifting heat around. But taking all the losses into account it is pretty unlikey that it could do much of that either. He needs a good haircut as well.
Nothing wrong with transferring heat into deep water, other than it raises the water temperature a teensy bit and increases sea level. It seems to me the idea they proposed is silly, but I’m teased by the engineering challenge.
They need hundreds of thousand ships with 1 km long pipe extended down plying the world’s oceans. Where will the ships get power for the pumps? Diesel? How much energy? 5 x 10^22 joules per year. Around 100 times greater than the world’s energy consumption.
“Their model showed that vertical movement of ocean water resulted in a decrease of clouds over the ocean and a loss of sea-ice.”
So conversely warmer SST causes more clouds and more sea-ice? Negative feedback anybody?
‘ “Our prediction going into the study was that vertical ocean pipes would effectively cool the Earth and remain effective for many centuries,” said Ken Caldeira. ‘
This is how to top up Trenberth’s missing heat – or has this already happened? Much, much higher standard of proof required before any geoengineering is even trialled, let alone implemented – the well-intentioned never think things through. I believe that is axiomatic of the left.
I believe the results of this study because they have been so successful
at modeling clouds and sea ice in the past. And there is no truth to the idea
that pipes will get fouled or corrode in sea water.
/sarc
Looking at the graphic I note that there are no cables running to the pumps from the generator. One must then assume the pumps are powered by solar and wind arrays. The 25 watt bulb sticking up above the waterline puzzles me. Is this intended as a navigation aid? Apparently grant money doesn’t buy much these days.
Put this in the same category as cast iron airplanes and tissue paper cars.
“we really don’t understand the atmospheric consequences of vertical ocean pipes”
There you have about as a succinct a synopsis of the true state of your actual Climate Science ( the real thing I mean not the 97% settled sort of ‘climate science’). By implication it also explains why the ‘models’ don’t seem to work any better than those 1:24 scale glue together plastic models of fighter planes actually took off and shot down ‘enemy’ models when I was a kid ( and I think that may still be the case). Damn that was frustrating!
Let’s cut to the chase; we are sitting on Magma, you know…molten rock! Why waste effort on warmish water/coolish water when you have LAVA! How many millenia would it take to suck the heat out of the center of this rock if we used our internal heat as THE energy source for 9 billion people?
The theory is the temperature difference between the upper ocean and the lower ocean provides a path for energy flow and generate electricity. This temperature difference provides “FREE” energy. The trouble in practice is the temperature difference is so small, it is not economical to use it to extract the energy. Free is one thing, but usable is quite another.
The temperature difference exploited in a coal fired generating plant is on the order of 900 degrees F. Plus additional heat is put into the steam at intervals in the extraction process to prevent condensation of water inside the power turbine.
I seem to remember a book I read about engineer’s dreams that had a story of this very process being tried around 1900 or so. A gentleman constructed a system that was tested off the coast of Cuba to test the idea. He lost all of his investment without producing any usable electricity.
Correct, see my comment at 6.12 am
Ridiculous to waste time thinking about this. Most of us have flown for Sydney to LA. There is a mind boggling amount of water in between, and that is almost the narrowest diagonal across the Pacific. Pipe dream is what this. Everyone should try to evaluate pragmatic solutions, not stuff that can be discarded before doing a feasibility study. CAGW is affecting everyone in really worrying ways. This sort of article is folly for this blog Anthony.
Forget the pipes, the CO2 sequestration or any other scheme that misses the obvious.
Just move civilization underwater where it’s cooler. The energy to run all of these underwater cities would come from…uh wait a minute, let me consult my geo-engineering handbook.
@DD More: “I could never understand how UHI was minimized. If you look at New York City as an example.
Area, including water 468.9 sq mi ( 2,590,000 sq m)”
I was never particularly good at math, so it is possible that I am missing something obvious, but here goes anyway: Exactly how does 468.9 sq. miles translate to 2,590,000 sq. meters? Can someone help me out here?
But all the missing heat has been transferred to the bottom of the ocean, where the water is boiling hot, right? We need old Kev to weigh in on this…
Wouldn’t it be simpler just to live at the bottom of the sea at a nice cosy 4degC……?
This is not a serious proposal, the handling of seawater is already a trouble, corrosion and fouling. The cycle has a low temperature driving force appr. 15 oC, the exchangers a LMTD of 5 oC . I would like to see the calculation for the heat pump cycle and ecomomics. Maybe there is just enough power left over for the light bulb in the diagram
The article might have another intention namely to prove the theory of the missing heat and that over 50 years from now Armageddon will happen.
One cynical observation: when people tell you that a global warming mitigation scheme won’t work because their climate model says so, you should consider the possibility that they are really saying that we should just bend over and take the medicine, for the good of our environmental souls.
And the medicine is: use less energy, consume less stuff, and, broadly, just be poorer.
Fine for hippies in California, less good for people on benefit in Geordieland or starving in Somalia.