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On Divestment Will Not Keep Carbon in the Ground

"Drving down the cost of clean energy technologies"

The following table from the MIT masters thesis of Shylesh Muralidharan shows the high capacity factor of OTEC as well as its competitive levelized capital cost with respect to other technologies. (Although not shown in this table the paper points to a study that shows a deep water condenser architecture can bring down the installed capital cost of a 100 MW plant ship from 4000 $/kw to 2650 $/kw.)

The thesis also shows that doubling plant size leads to a cost/kW reduction of OTEC plants by approximately 22%.

Using CO2 as a working fluid for the deep water condenser design allows for plants of gigawatt capacity.

Extrapolating for a 1 GW plant of the deep water condenser design, it would cost $86*2650/4000*78/100*(1-(.22*(200/800))) or 42 $/MWh for the lowest levelized capital cost for all energy sources but for combined cycle natural gas and would be the cheapest of all renewables.

It is this capacity to scale to low cost combined with the environmental dividends inherent in the production of energy from this source that makes it truly transformational.

(Seeking collaborators to capitalize on this environmentally and economically effective prescription.)

January 28, 2015    View Comment    

On 2014 Was the Warmest Year Globally Ever Recorded

Heat moved to the depths is heat unavialble to warm the air, create storms or melt icecaps or permafrost.

The movement of all of the heat being absorbed by the ocean - mostly occuring in the upper 10 meters - to 1000 meters - through a heat engine - would produce more energy than we currently derive from fossil fuels.

Problem solved!

Planet saved!

January 21, 2015    View Comment    

On Prescribing a Cure for the Health of Both the Planet and its Inhabitants

"Scientific progress is as unlimited and at least as rapid as that of population,” Engels, 

The oceans are a huge resource that OTEC allows use to tap into.

January 17, 2015    View Comment    

On Prescribing a Cure for the Health of Both the Planet and its Inhabitants

OTEC has been promoted on the basis of that benefit. Phytoplankton blooms however precede the creation of an oceanic dead zone - too much of a good thing turns out to be a very bad thing. Areas that are associated with natural upwelling also have a lower pH, which is detrimental to shell-forming organisms.

January 17, 2015    View Comment    

On Prescribing a Cure for the Health of Both the Planet and its Inhabitants

Hops, it is just the reverse. The oldest and deepest water masses have the highest concentrations of carbon dioxide because as it dies aquatic life sinks. if you look at the Geoengineering Technology Options shown in Roman Kilisek's post, enhanced downwelling is one of the options. My preferred option however does not move water between the surface and the deep. It moves the heat instead with phase changes of the wroking fluid. This is faster, less costly and more environmentally sound because entrainment and impingement of aquatic life is not an issue and there is little potential to release disssovled CO2 in the deep into the atmosphere.  


January 17, 2015    View Comment    

On Climate and Global Energy: The Answer Lies After 2050, Probably Not Before

I have never disputed the frozen methane issue. I do however argue that heat in the atmosphere or near the ocean's surface is more likely to melt clathrates than heat moved to deeper water with ocean thermal energy conversion. Surface tropical heat migrates towards the poles and it is frozen methane in the permafrost that Hansen suggests  can be released unleashing powerful feedback forces that might lead to runaway climate change. Oceanic clathrates are found along the continental shelves and these shallower waters are warming faster than deep water, therefore surface heat moved to deeper water will have little to no effect on frozen oceanic methane. In turn it is no longer available to melt permafrost.

January 15, 2015    View Comment    

On Everything Has Changed: Oil, Saudi Arabia, and the End of OPEC

Elias, thank you for describing the rationale for the Saudi's Fossil Fuel Blowout so eloquently.

January 9, 2015    View Comment    

On Baked Alaska: Climate Change in the Arctic

Ike, Ocean Thermal Energy Coversion, using a heat pipe design would convert 14 TW of surface heat to power, what we currently get from fossil fuels, while moving about 280 more TWh to the abyss due to the low thermodynamic efficiency of the process. This is close to the 330 Twh NOAA says the oceans have been accumulating annually due to cliimate change. This shortcircutis the movement of tropical heat towards the poles and the thermal coefficient of sea water at a depth of 1000 meters where the surface heat would be relocated is half what it is at the tropical surface.

The trade winds are only increasing the thickenss of the termocline by 50 mters in the Eastern Pacific.

When they shift this heat will slosh back to the surface as it may even be doing currently. Heat moved below the thermocline however diffuses back to the surface at a rate of 4 meters/yr according to the presentation of Norm Rogers to the 2012 AGU so heat moved to 1000 meters would take 250 years regardless of which way the wind blows. Plus OTEC would constantly moving heat to these depths while producing as much energy as we currently get from fossil fuels, thus the atmospheric levels of the greenhouse gas would gradually declone.

In short I am not suggesting geo-engineering. I am suggesting energy production that address both the cause and worst consequences of climate change.

January 5, 2015    View Comment    

On Baked Alaska: Climate Change in the Arctic

Tom, Jesse Farmer in his article, 400 ppm World, Part 1: Large Changes Still to Come points to the fact that the last time CO2 levels where at 400 ppm, in the Pliocene, the average temperature of Ellesmere Island, in the Arctic, was 32oF higher, whereas along the East Coast of the United States they were likely 5 degrees warmer on average than today. This is a pretty clear indication of the kind of polar amplification that can be expected, which I see as the second law of thermodynamics in action as excess heat moves from the warmer to the colder region. This is why I believe it is imperative, if we want to avoid massive sea level rise, to move this heat instead into the other massive cold sink that is available, the ocean abyss. This movement would as well afford us the opportunity to produce as much energy as we currently derive from fossil fuels.


January 3, 2015    View Comment    

On The Ideal City in 2030: How Carbon 'Negative' Cities can Generate the Greatest Positive Impacts

Dumping heat into the ocean in the production of enough energy to replace fossil fuels can delay the problem long enough for atmospheric CO2 to return to pre industrial levels  Subsequently the dumping can be cut back to allow return of the heat to the atmospheric in tolerable measures. 

December 31, 2014    View Comment    

On The Ideal City in 2030: How Carbon 'Negative' Cities can Generate the Greatest Positive Impacts

"Dumping heat in the oceans", it is already there, 93 percent of the heat attributed to global warming. Most of it accumulates near the equator and the mass-flow from there is towards the poles, often in the form of cyclones or smaller storms. It is this heat that causes icecap melting that will be the driver of truly massive sea level rise. The coefficient of thermal expansion at 1000 meters is half that of 28-30C in the tropics. Drop that temperature below 27C and cyclones cannot form. A drop of 3C of the upper 50 meters would equate to less of a raise in the deep due the much greater volume but even if it did rise by 3C the thermal expansion would be less. Some claim thermal expansion would increase because the surface would just absorb additional heat. NOAA estimates the cooling of the ocean surface due the conversion of heat to mechanical energy in a hurricane is between  0.2 and 1.2°C. That is not generally immediately replenished otherwise you would have serial storms in the same locations. Even if thermal expansion would increase though because surface heat was replenished this would be much less of a sea level threat than icecap melting that would be short-circuited by the movement of heat to the deep.

I have seen the convection-tower models as well. The first thing that strikes me is those who complain about windmills certainly wouldn't want one of those things in their backyard. That is one of the beauties of OTEC is that it is no ones backyard and furthermore out of sight and out of mind in most instances.

Happy New Year.


December 30, 2014    View Comment    

On The Ideal City in 2030: How Carbon 'Negative' Cities can Generate the Greatest Positive Impacts

EP the heat engine produces work by bringing a working fluid from a higher temperature to a lower temperature. The ocean's surface has an excess of heat due to climate change, Its depths are virtually untouched as a heat sink. With the carbone-free energy you can produce from these resources you can sequester carbon, desalineate water, produce fuels such as hydrogen or ammonia, all whie mitigating the greatest risks of climate change. The key is to making it cheap. A heat pipe reduces the cost by as much as 45 percent over conventional, cold water pipe, designs and mass production and further development would also help.

December 29, 2014    View Comment