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On Short-Circuiting Sea Level Rise

Wikipedia, a 100 MW OTEC power plant would require 200 exchangers each larger than a 20 foot shipping container. A 20 ft container is 33 cubic meters thus 200 is 6600 cubic meters. A far cry from 27,000,000.

October 15, 2014    View Comment    

On Short-Circuiting Sea Level Rise

Vega's design for a 50 MW plant moves 142,300 kg/s of cold water to the surface to condense 2,750 kg/s of anhydrous ammonia. With the heat pipe it is only the working fluid that is circulating between the surface and the cold sink thus there is at least a 50 percent improvement in terms of parasitic losses.

October 15, 2014    View Comment    

On Short-Circuiting Sea Level Rise

Between the evaporator and condenser is 800 meters of vapor pipe exposed to cold water below the thermocline, which further facilitate the condensing process.

October 15, 2014    View Comment    

On Short-Circuiting Sea Level Rise

Oliver, Prof. Gerard Nihous of the University of Hawai is considered the authority on the amount of energy that can be produced with OTEC. In his latest work he puts that potential at 14TW or 250,000 100 MW plants. This is what we currently get from fossil fuels but others have put the potential as high as 25 TW. This energy will be produced in the tropics and will require an energy carrier like hydrogen to get it to market. (Don't forget much of the world's oil and gas comes from the Middle East requiring transportation over equally long routes.)

Also that tropical heat is driven by the second law of thermodynamics towards the poles where it melts the icecaps.

A group lead by Greg Rau of the University of California Santa Cruz have developed a technique for producing "supergreen" hydrogen by the electrolysis of sea water that removes and stores atmospheric carbon dioxide while generating carbon-negative hydrogen and producing alkalinity, which can be used to offset ocean acidification.

Your wikipedia link points out the thermally efficiency of OTEC has a theoretical maximum of 6 to 7 percent but in reality existing efforts are half that.

A 2010 NOAA study found the upper layer of the world’s ocean was storing enough energy to power nearly 500 100-watt light bulbs per each of the roughly 6.7 billion people on the planet - . I make this to be about 335 terawatts.

The thermal efficiency of the heat pipe design is about 5 percent so to produce 14 TW with the design you would have to pump 280 TWh into the deep and the conversion would bring the benefit to 294TW or just about all what is currently being added.  And with the heat pipe you pump zero water from the depths because only the working fluid vapor is moving from the surface to the cold sink, where it is condensed and then pumped back again. This requires the movement of about 8 m3 of ammonia for a 50MW plant as opposed to about 150 m3 of water every second. The parasitic losses of this system are about half of the other.

There are a lot of climate and energy wins with such a system.


October 14, 2014    View Comment    

On Energy With Benefits

Figure 1: components of  global warming for the period 1993 to 2003 calculated from IPCC AR4

From Skeptical Science article

This is supported by the latest Deep Argo research.

October 14, 2014    View Comment    

On Energy With Benefits

Thanks for the support Max. Hopefully you will learn more in a post I believe will be out today related to a Simon Fraser University competition regarding sea level rise.

October 14, 2014    View Comment    

On Energy With Benefits

Max lack of funding has insured the modelling we all seek is non existant. I am collaborating with a group that includes a former Chief Technologist with NASA and the Director Emeritus with the Hawaii Natural Energy Institute of the University of Hawaii. Both of these gentlemen have been associated with OTEC from the outset. We also have two engineers, one of whom who has long experience with OTEC, a PhD in Physics with over 20 patents and Dr. Greg Rau of the University of California, Santa Cruz. He is a collaborator in the University of Victoria Water and Aquatic Sciences Research Program as well as our conscious and advisor on the issues that concern you. It is his assessment that there are a lot of environmental winners associated with the deep water condenser OTEC design. He also has developed a hydrogen production technique that removes and stores atmospheric carbon dioxide while generating carbon-negative hydrogen and produces alkalinity, which can be used to offset ocean acidification. It is a natural adjunct to our OTEC technology because an energy carrier is required to bring the ocean generated energy to shore. Believe me we have debated these issues extensively and are actively seeking the funding necessary to first properly engineer the system, then build a small ocean going prototype to test it  and then slowly begin the build out of the systems that Paul Curto, formerly with NASA, has remarked is by far the most balanced means to face the challenge of global warming

October 14, 2014    View Comment    

On Should the Climate Movement Turn Down the Radicalism?

Neil, the Harper Government in Canada represents the flip side of this argument.

As Andrew Leach, the Enbridge Professor of Energy at the University of Alberta points out in an article today, "They chose to kick sand in the face of the environmental movement in Canada. They chose to talk down to American objections. They chose to take a very heavy-handed approach in terms of talking up the possibility of not needing the U.S. market."

Michael Cleland, the Nexen executive-in-residence at the Canada West Foundation says in the same article, concerning the impact of the government's actions on the oil and gas industry, "The loss of public support, I think it borders on being crippling."


October 13, 2014    View Comment    

On George Shultz: "Climate is Changing," and We Need More Action

“One of the real breakthroughs is when someone figures out long-term storage capacity,”

Nature figured that out decades ago. She is storing heat that otherwise would be baking us in the ocean.

The breakthrough will occur when sufficient numbers of us understand that the conversion of this heat to usable power and the movement of 20 times more into the deep ocean remedies the problem.

James Hansen has advised, “The rate of ocean heat uptake determines the planetary energy imbalance, which is the most fundamental single measure of the state of the Earth’s climate."

In a Nature article, whe he was asked, "Is climate change going to be less extreme than you previously thought?" James Lovelock replied, "we were all so taken in by the perfect correlation between temperature and CO2 in the ice-core analyses [from the ice-sheets of Greenland and Antarctica, studied since the 1980s]. You could draw a straight line relating temperature and CO2, and it was such a temptation for everyone to say, “Well, with CO2 rising we can say in such and such a year it will be this hot.” It was a mistake we all made.

We shouldn’t have forgotten that the system has a lot of inertia and we’re not going to shift it very quickly. The thing we’ve all forgotten is the heat storage of the ocean — it’s a thousand times greater than the atmosphere and the surface. You can’t change that very rapidly."

It is time to stop being taken in by climate and energy solutions that have little to no real impact.

October 5, 2014    View Comment    

On Can CDR Give New Life to Comprehensive Carbon Pollution Legislation in the US?

James Hansen et al. point out in the paper Earth’s energy imbalance and implications that   "The rate at which Earth’s surface temperature approaches a new equilibrium in response to a climate forcing depends on  how efficiently heat perturbations are mixed into the deeper ocean."

Fossil fuel interest can offset the damage they are creating by forcibly mixing the accumulating warming heat - over 90 percent of which is in the upper 700 meters of the ocean - deeper.  A heat pipe is the most efficient mechanism for moving heat from a location where it can do damage to a benign heat sink like the deep ocean. Absent moving parts it moves heat through the phase changes of the working fluid. Passing a vaporized working fluid which extracts surface and atmospheric heat in the form of latent heat of evaporation through a heat engine it is estimated the oceans have the potential to produce at least as much energy as is currently derived from fossil fuels.  The surface heat is then deposited at a depth of 1000 meters in the form of the latent heat of condensation at the condenser. At this depth the coefficient of expansion of ocean water is half that of the surface from which the heat has been removed thus one of the greatest risks of climate change, sea level rise, is diminished. As the rate of return of heat from the depths is estimated at 4 meters/year it would take 250 years for the relegated heat to migrate back to the surface, where it could again be forcibly return.

It will take probably a century or more to build out this zero emission energy system that can replace fossil fuels even as it remedies the damage the burning of the same  has and will cause.  In the remaining 150 years that it would take for the first relegated heat to start reemerging the atmophere will have begun recovery.

If the fossil fuel industry is to avoid the stranding of its assets and replace those it is depleting along the same time line, it will support the build out of ocean thermal energy conversion systems designed to foreceably move heat into the deep ocean. There are after all in the energy game and can remain so in the transition.

As is clear from the chart shown in this presentation, CDR is a fairly insignificant wedge and thus not much of a hedge against the stranding of their existing assets.


September 25, 2014    View Comment    

On Climate Change: Is Failure Now Inevitable?

James Hansen et al. point out in the paper Earth’s energy imbalance and implications that   "The rate at which Earth’s surface temperature approaches a new equilibrium in response to a climate forcing depends on  how efficiently heat perturbations are mixed into the deeper ocean."

You are undoubtedly right Robert, that we will not keep atmospheric CO2 levels below 450 ppm. That does not preclude us however from avoiding the predicted consequences of this much greenhouse gas in the atmosphere. We can forcibly mix the accumulating ocean heat -over 90 percent of global warming heat - into the deeper ocean and produce at least as much energy as we currently derive from fossil fuels. From a depth of 1000 meters Norm Rogers predicts it would take 250 years for this sequestered heat to migrate back to the surface. One hundred years or so of carbon free energy in the mean time would drop CO2 levels so that the reemergence of this heat or its forcible return again to the depths would be uneventful.

A colleague suggests it would take every shipyard and every mine on the planet working at full tilt to produce the infrastructure for 2.5 terawatts of OTEC derived power. I would think this would be well received in Glasgow?

By the way you can also fly planes on hydrogen or ammonia just as you can operate cars on these fuels. Airbus and Boeing have or are researching fuel cells and hydrogen works in a turbine as well.


September 22, 2014    View Comment    

On Hope For an Energy Rich, Sustainable Future

Max, Naomi Klein's latest book castigates capitalism for its impact on climate change. Overly cautious environmentalism and environmentalism with an agenda beyond resolving the problem are no less problematic in my view.

September 18, 2014    View Comment