Comments by Jim Baird Subscribe

On OTEC and Energy Innovation: The Willie Sutton Approach

CO2 becomes a supercritical fluid  at 31°C and 73 atm. The closer it gets to this temperature and pressure the more it acts like a liquid and thus the less volume you need to move a turbine.

Melvin Prueitt's patent Heat Transfer For Ocean Thermal Energy Conversion shows a table of various working fluids and the work you can get out of them using a heat pipe of 1 meter in diameter. He was a physicist with Los Alamos and calculted these figures on a program OTEC.exe which is propriatary to DOE.

Heat moves in a heat pipe in vapor because the pressure at the evaporator end is greater than at the condensing end. The rate can approach the speed of sound. You don't have to pump the vapor down.  You have to pump the fluid up.

Hopefully the Prueitt explains the process more effectively than I can.

On OTEC and Energy Innovation: The Willie Sutton Approach

Rob, many of the ocean areas conducive to OTEC are also increasingly becoming dead-zones due to eutrophication and over-fishing. I see the oxygen in part being a solution to the eutrophication problem and if Boyce is right, and we are losing the initial source of the atmosphere's oxygen and a current source of 50%, then that which is not dissolved en route to the surface would replenish the phytoplankton shortfall.

Hydrogen is hard to transport but it can be converted at its source to NH3 or CH3OH which are not but are non or low carbon transportation fuels. My preference would be to work of the transportation problem however because hydrogen is as much a water currency as it is an energy currency and the production of both at the point of need addresses two needs.

I became interested in OTEC in the 80s while working on a book plotted around the extraction of the ocean's vast, dissolved, resources which OTEC could make available. The interest was revived a few years ago when thinking of ways to combat sea level rise and more recently by the potential to limit storm damage.

OTEC could address the sea level problem five different ways even as it provided all of the energy we need; converting heat to work to reduce thermal expansion, electrolysis to convert liquid volume to gas, desalination - OTEC Open Cycle - and terrestrial use of ocean volume, movement of surface heat to the depths where the coefficient of expansion of at 4C is half what it is at the surface, and the sapping of ocean surface heat that causes storms which in turn are the main driver of tropical heat towards the poles, which in turn is melting the icecaps and permafrost.

It is a costly approach, but again the heat pipe reduces the main driver of this - the cold water pipe - from a diameter of 14 meters to produce 100MW to 1 meter and thus the supporting infrastructure can also be massively reduced. And I believe its cost deserves to be offset by the savings derived from limiting SLR and storm damage.

With respect to stored thermal energy I trust the following two diagrams are self explanatory.

Re cost effectiveness, I fully agree with IK's most recent post that, "prototypes should be built and tested that's the only way to encounter the full range of problems you would not predict."

On OTEC and Energy Innovation: The Willie Sutton Approach

A hurricane is effectively an atmospheric heat pipe releases heat energy at the rate of 50 to 200 exajoules (1018 J) per day, equivalent to about 1 PW (1015 watt). This rate of energy release is equivalent to 70 times the world energy consumption of humans and 200 times the worldwide electrical generating capacity, or to exploding a 10-megaton nuclear bomb every 20 minutes. Wikipedia. Hurricanes operate on the same thermodynamic limit of about 20C. There are as many as 21 major storms a year even though there is a major release of heat in each storm because most of the heat of evaporation in returned in the latent heat of condensation of raindrops. A heat pipe would return heat to the surface in the condensed fluid the same way.

Nature can destroy use or we can learn from her example?

On OTEC and Energy Innovation: The Willie Sutton Approach

A heat pipe helps by moving heat with phase changes of the working fluid as opposed to bringing the cold sink essentially to the surface with a massive movement of water. The heat pipe is a closed system, 1/10 the pipe size, and the fluid and vapour movement is in isolation from the bioshere. You would need a large volume of working fluid but with CO2 this is neither a great cost nor risk.

On OTEC and Energy Innovation: The Willie Sutton Approach

Rob my only quibble is; oil from the Middle East also has transits great distances to reach its market. Converting ocean energy to an energy currency with electrolysis addresses sea level rise by converting liquid to gas and OTEC conversion of heat to work reduces thermal expansion as well. As to operating fluids James Lau suggests CO2, which would not be environmentally risky. 

On Climate Change and the Carbon Bubble Reality Check

Schalk, I have no objection to CCS provided those who are profiting from polluting the planet pay for it. Otherwise the 99 percenters are paying triple, for their profits, for the damage and now they would have us pay to clean up there mess, even as they rake it in hand over fist.

My grandfather was an Alberta rancher 100 years ago.

I know BS when I see it.

This is IT!

I am not an advocate of solar or wind. OTEC however is 3 times as efficient as either due to the intermittence factor and addresses the existential threat to my grandchildren, which I take seriously.

In an earlier post you claimed this solution was too resource intensive - massive structures - and that the production of power mid-ocean was a long shot.

Oddly enough Middle East petroleum has to transit these very same oceans, which contained tremendous mineral potential in solution.

OTEC provides both the energy and water movement to access this plenty and remedies the environment even as it produces all the energy we need.

On Climate Change and the Carbon Bubble Reality Check

Or you can dig holes in the ground to produce carbon emitting products that cause $4.5 trillion dollars a year in environmental damage.

Or you can delay tackling global warming for seven years at a cost of an additional $5 trillion, 

As a Canadian taxpayer, if CCS is so great then one of the most profitable enterprises on the planet - the one Mr. Hone works for - can pay for it.

My children and I would prefer our taxes went to pay for what needs to be done, now!

On Climate Change and the Carbon Bubble Reality Check

Rick, the proposal to move water from areas of excess to areas  of shortage is a seperate issue from OTEC. I believe the problem of sea level rise can be addressed six ways. Replacing water being drawn from aquifers with water from areas that have excess and using the excess water to recharge aquifers already depleted is one of them and the subject of the recent article.

The other five ways have an OTEC component but they are a separate issue and probably not as easily addressed.

As is happening now, my grandfather's home on the outskirts of Winnipeg was washed away by the Red River in I believe 1949. The southwest could certainly use some of the water flowing north in that basin today which will end up in Hudson Bay producing a little hydro power en route as it ultimately contributes to global sea level rise.

On Climate Change and the Carbon Bubble Reality Check

Schalk, how is it that costs which sustain the status quo -CCS - are good, whereas costs that would mitigate climate change bring about economic collapse?

A trillion dollars either way is a trillion dollars added to GDP is it not?

On Climate Change and the Carbon Bubble Reality Check

Rick it isn't missing from TEC, Climate Change and Anthropogenic Sea Level Potholes.

NOAA points out in the following diagram climate change will make the wet latitudes wetter and the dry dryer over the coming century. There are ways that these changes can be leveled.

Currently we are trying to remedy shortages by pumping aquifers dry, which is only contributing to sea level rise.

Mr. Hone once commented this was the "real" climate issue.

We could mitigate it in part by recharging the world's aquifers with excess water from the regions that are and will increasingly be flooded.

On Climate Change and Anthropogenic Sea Level Potholes

Renewable water resources are defined as the average manual flow of rivers and recharge of aquifers generated from precipitation. 70 percent of this precipitation originates in the ocean and all of the renewable water ultimately ends up there otherwise we would be living in arks. No one is talking about depriving the salmon or rain forest.

If your neighbour smokes in bed and sets his house on fire, does that mean you shut off your tap to teach him a lesson.

I wasn't brought up that way.

We have 20 percent of the world's fresh water and less than a half a percent of global population.

We need all of this?

Hardly!

On 100 Percent Renewable Energy is 100 Percent Possible

I realize it is a great deal of heat and that is why I worked on the counter-current heat transfer system to try to find away around dumping that much into the deep. As was pointed out to me by Martin Hoffert 30TW would probably be enough to overturn the Thermohaline circulation using the conventional approach.

Gerard Nihous thought only a few years ago 5TW was the upper limit for OTEC because it would dump so much heat the Carnot efficiency would drop even lower. His work was the impetus for trying to find a way around the problem in the first place.

Thank you for your input.