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On Nuclear Energy Innovation Big and Small Important to Climate Change

“Nuclear is currently the only carbon-free energy source that can provide base load electricity — a characteristic crucial to reducing global greenhouse gas emissions.”

Wrong!

According to Rod Fujita, Director of Research and Development, Oceans Program for the Environmental Defense Fund, Energy From The Sea: Closer Than You Think.

He also coauthored a paper Revisiting ocean thermal energy conversion which concluded a Lockheed Martin/Reignwood Group project to develop a 10-megawatt power plant in southern China was the missing link in commercializing OTEC. As he says, “Several small OTEC plants have been built already, so we know that the concept produces net energy. . . But the costs associated with scaling OTEC up have been very uncertain, perhaps scaring off potential investors and customers up till now.

Conventional OTEC’s cost is driven by the size of the cold water pipe required to move large volumes of water to overcome the low thermodynamic efficiency of the process. With a delta T of about 21C the theoretical Carnot Efficiency is about 7% but practically it is less.

According to a design of Luis Vega and Dominic Michaelis for a First Generation 50 MW OTEC Plantship for the Production of Electricity and Desalinated Water, 264.6 m3/s (270,400 kg/s) of warm water; and 138.6 m3/s (142,300 kg/s) of cold water are moved to produce 53.5 MW.  This facility employs 2,750 kg/s of anhydrous ammonia as the working fluid and with a density of 681.9 kg/m3 this equates to 4 m3/sec.

Dr. Fujita claims “OTEC is definitely not a panacea.  Using large amounts of cold, nutrient rich water from the deep ocean in order to produce energy could have some very negative impacts, like killing sea life by sucking it into the intake pipe or creating algal blooms by discharging nutrient rich sea water into warm, nutrient-poor surface water. But these and other impacts can be prevented or mitigated.”

It is the movement of such a large volume of water that has the potential to negatively impact sea life, create algal blooms that produce dead zones in the ocean and potentially release CO2 into the atmosphere as the gas dissolved in the water under pressure is brought nearer the surface.

The best way to prevent this is to use a heat pipe as shown in Dominic Michaelis’ British Patent No. GB 2395754.

As Paul Curto, former NASA Chief Technologist points out, “if the condensing end of the heat pipe is exposed to a thousand feet or more of near freezing temperatures below the thermocline, no cold water pumping is required. The parasitic losses are cut in half. The costs for the cold water pipe are eliminated, along with the cold water return pipe and condenser pumps, the cleaning system for the condenser, and the overall plant efficiency approaches 85% of Carnot vs. about 70% with a cold water pipe.

The parasitic losses could be reduced as much as 50% and the complexity, mass (and cost) of the system reduced by at least 30%. The vast reduction in operating costs and environmental impacts would be worth investigation alone”

Relative to the above 53.5 MW plant, you would only move 4 M3/sec of working fluid in a close system and therefore would not impact sea life, create dead zones or release CO2.

Considering the current estimates for the amount of energy you can produce with such a system is 25 TW and the world operates currently on only 16TW then OTEC starts to look more and more like a renewable energy panacea.

Dr. Melvin Pruiett, Ph.D. in Physics and former guest scientist with Los Alamos National Laboratory has another patent application for a Heat Transfer For Ocean Thermal Energy Conversion system, that uses a heat pipe design to absorb heat in a heat exchanger near the ocean surface using the latent heat of evaporation and then deposits the latent heat of condensation in a deep ocean heat exchanger, using the cold seawater as a heat sink. The condensed liquid is pumped back to the ocean surface. The heat engine (turbine) and generator can be at the ocean surface, or it can be in deep ocean. By using a fluid that transfers heat by evaporation and condensation, much larger quantities of heat can be moved per kilogram of fluid than can be transferred by moving the same mass of seawater.

Dr. James Chung-Kei Lau, Ph.D. in Physics, 20 patents, has a patent application for an Ocean thermal energy conversion (OTEC) electric power plant, which uses CO2 as the working fluid, necessitates no water pumping because of the distributed nature of the evaporators and condensers. The design uses a heat pipe to communicate the working vapour between the evaporator and condensers.

Nagan Srinivasan; has a patent application for an Offshore Floating Platform With Ocean Thermal Energy Conversion System,  in which heat is extracted from warm sea surface waters to vaporize a liquid working fluid and heat is rejected to cold water from lower depths of the sea to condense the vaporized working fluid. At least one turbine and power generator is disposed on the deck, at least one evaporator is disposed on the platform beneath the deck, and at least one condenser is disposed on the seabed or platform or keel tank a distance beneath the evaporator.

This too is a heat pipe design combined with an adapted oilfield type platform which the inventor claims can produce 1000 MW at a capital cost of 3billion USD.

By comparison the two 1200 MW nuclear reactors to be build at the Vogtle site in Georgia are expected to cost $14 billion or nearly twice as much.

With the OTEC plant there would be no fuel or waste cost. Decommissioning would be much simpler and a catastrophic failure would be far less of a catastrophe.

If CO2 was the working fluid it would be virtually benign.

The claimed shortcoming with the heat pipe design is the low pressure working fluid vapour inside a pipe subjected to the pressure of 1000 meters of water.

The writer has a patent application for an Ocean Thermal Energy Conversion Counter-current Transfer System that overcomes this by use of a coil inside the vapour channel acting against the external pressure. The coil returns the condensed working fluid and acts as a condensing surface upon which the vapour condenses. In the process the internal fluid absorbs part of the latent heat of condensation and returns this to the surface.

At the time this patent application was filed it was estimated the oceans could only produce about 5 terawatts of power because as more and more surface heat was transferred to the depths with OTEC the thermodynamic potential of the ocean would degrade. The counter-current system was developed to prevent this degradation and increase the potential of the ocean to produce power.  Subsequently the same researcher has raised his estimate to 25 terawatts, which would be assured with the counter-current system shown below, which also counteracts the crushing forces exerted on the heat pipe.

 

With deference to Dr. Fujita, it is OTEC innovation that brings about an energy panacea that addresses the sea level problem 5 ways. By:

  • Converting surface ocean heat to work, thus reducing thermal expansion.
  • Moving surface heat to a depth of 1000 meters where the coefficient of expansion due to pressure and water temperature is half that at the surface.
  • Converting liquid volume to gas by electrolysis to produce hydrogen as the energy carrier to bring power ashore.
  • Some versions desalinate water for use on shore, and
  • By sapping tropical surface heat that otherwise drives storms, which move tropical heat towards the poles causing the icecaps to melt.

As Dr. Pat Takahashi, Director Emeritus of the Hawaii Natural Energy Institute at the University of Hawaii and co-founder of the Pacific International Center for High Technology Research, recently posted, OTEC is the only energy option with any kind of chance for making a real contribution to the climate problem.

 

June 26, 2013    View Comment    

On Pandora's Promise, Nuclear Energy Documentary, Asks: What Are You Wrong About?

When the industry and its political backers maintain placing waste on top of a modern volcano is a sound idea; is there any wonder there are trust issues?
June 26, 2013    View Comment    

On Pandora's Promise, Nuclear Energy Documentary, Asks: What Are You Wrong About?

Alex, geologic disposal is a matter of geology. Some of the world's top scientists in the field put the lie to your thesis, but if you want to talk nuclear physics, Russia's top man in the field, Yevgeny Velikhov of the Kurchatovsky Institute stated in an article, World has no feasible project yet to liquidate nuclear waste: Out of 14 versions of liquidating nuclear waste in some countries ... only three can be examined dead serious. Ship it to the sun, put it in the Antarctic ice cap and place it in the earth's crust at great depth so it can melt into the plasma of the earth later.

If you place waste in a subduction zone you can rest assured it will be dissolved in the mantle in 10 million years.

Where Oklo's fission products went or when, God only knows.

Anything but a good example of radionuclinde sequestration.

June 26, 2013    View Comment    

On Pandora's Promise, Nuclear Energy Documentary, Asks: What Are You Wrong About?

In the Nature article, "The Geology of Nuclear Waste Disposal," 310, 537 (1984) some of the world's leading geo scientists said Oklo was a worst case example because the daughter products of Plutonium fission are missing.

Their conclusion, "disposal in subduction trenches and ocean sediments deserves more attention."

The Oklo Phenomenon

"The relevance of nuclide migration at Oklo to the problem of geologic storage of radioactive waste was discussed and it was indicated that in the Oklo geochemical environment during the past 1800 million years the fission product elements which migrated significantly were Kr, Xe, Cs, Sr, Ba, Mo and I. Two of the mobile elements are important from a nuclear waste storage point of view, Sr and Cs, and it has been indicated that the mobility of Sr was not sufficiently great to result in its total displacement."

 

June 25, 2013    View Comment    

On Climate Change and the Energy World Map

Schalk, there is nothing stopping fossil fuel providers from implementing their own CCS programs and building the cost into the cost of their products. This way the market determines the true cost of carbon and ff and renewables providers compete on a level playing field.

If they were serious in their climate concerns, this is what they would do.

 

June 20, 2013    View Comment    

On Renewable Energy Grid Parity Reality Check

The whole point of OTEC is it converts heat that may well make the planet unliveable to work. There is no other way to deal with it.

June 18, 2013    View Comment    

On Renewable Energy Grid Parity Reality Check

Thanks George. I hope to cover both issues in two forthcoming posts.

June 18, 2013    View Comment    

On Climate Change and Driving the Hydrogen Highway

Great news Bob. The overlooked subtext of this article is; Canada has excess water it refuses to export to the drought stricken Southwest. Hydrogen is as much a water carrier as it is an energy carrier. Perhaps Canada could be convinced to export hydrogen for the purpose of meeting the need. Or better yet they will realize the better alternative would be to ship the water and the hydro-power such a transfer would enable.

I suspect the same public that protest water sales would be happy to sell hydrogen?

June 18, 2013    View Comment    

On Eternal Energy Production

Alistair, there have been a number of experiments and Lockheed Martin and a Chinese company have signed an agreement to do a 10 MW plant. I hope to have more on this subject in an upcoming post.

June 17, 2013    View Comment    

On Climate Change and Driving the Hydrogen Highway

Paul re: separating elements or separating Isotopes. As Garwin has pointed out reactor grade plutonium is weapons useable regardless of the Pu240 content. I talked to a guy who used to work for the Atomic Energy Control Board in Canada though and he thought it might be possible to separate isotopes as well with spallation, which is the process Dr. Eastland was working on. I had some correspondence with him as well about waste disposal options. Neither his nor mine were ever adopted and I think the nuclear industry missed a couple of good opportunities as a result.

Yevgeny Velikhov of the Kurchatovsky Institute wrote an article, World has no feasible project yet to liquidate nuclear waste, in which he stated. Out of 14 versions of liquidating nuclear waste in some countries ... only three can be examined dead serious. Ship it to the sun, put it in the Antarctic ice cap and place it in the earth's crust at great depth so it can melt into the plasma of the earth later.

Subduction zones are conveyers of nuclear waste to the earth's mantle.

June 16, 2013    View Comment    

On Climate Change and Driving the Hydrogen Highway

Dr. Cannara designed analog and digital instrumentation, applying for a patent on one design.

Why so?

June 16, 2013    View Comment    

On Climate Change and Driving the Hydrogen Highway

 No problem Paul. I hope to cover the social license and new OTEC technologies issues in upcoming posts.

June 16, 2013    View Comment