Worldwide production down 400,000 bpd in March to 84,047,000 barrels per day.

Go nuts, peaksters. The end is here.

The EIA released its monthly numbers. That's 700,000 barrels less than December, for those of you keeping track.

For Rarotonga, this could be the way to go.  But OTEC won't play any significant role during the world energy crash and dieoff.  It is too late in the game.  OTEC will be a technology adopted by some of the dieoff survivors.

One third of Americans think they will see a UFO before their car runs on corn-juice

It all gets down to the amount of capital investment in relation to the amount of energy that can reasonably be expected to be extracted over the life of the system.

Maybe somebody will make it work more successfully and cost-effectively than it has, but I wouldn't hold my breath.

Yes, a huge amount of energy is bestowed upon the oceans, but the rub is being able to extract it in a practical, survivable, and cost-effective manner.

I wouldn't give up on any of these alternative energy schemes, for the calculus of what's reasonable and what's unreasonable may change quite suddenly should the fossil fuel situation start to tank sooner than expected.

Upshot is, Townsville is poorly placed due to the continental shelf being a long way offshore (100km), but points further north in Queensland (e.g. Cooktown) could be suitable due to the shelf being much closer to shore. However Townsville was still seen as a potential engineering base for a future industry to support OTEC applications for pacific islands.

Unfortunately I didn't find any concrete progress towards commercialisation of the technology in Australia.

I'm unclear about the mechanism that these systems use.  The beauty of this source seems to be that, since the potential is so enormous, we can consider relatively inefficient generation and still be in the black economically.

how about a Stirling engine or, like the fan on my woodstove, utilize the Peltier-Seebeck effect?

And now I'm going to say something that some people may not like.

Every day, there is a Drumbeat open forum. But every thread on a specific subject like this one is used as an open thread. I note some comments above that are certainly interesting but completely off-topic. Perhaps TOD commentors could put the off-topic subjects on the readily available open threads and focus on the topic being discussed. Rick has made a serious effort here and it deserves discussion in its own right. I am not trying to stifle TOD comments. I just think they belong where they belong. And the length of the Drumbeat open threads is no excuse.

'nuff said.

Dave

If used on a large scale the potential for warming the water enough to cause signifcant. The interaction of ocean current with water thats several degrees warmer is unpredictable.

I suspect any large scale deployment would have to be far from
methane hydrate deposits and even then the effects on currents
could cause the water to move a significant distance before cooling.

It's not just the lifeforms that will react to warming - The solubility of CO2 declines dramatically with increased temperature, given constant pH. But the most nightmarish possibility is the initiation of an instability event like that seen in Lake Nyos, Cameroon, in, when was it, 1980? Only in this case, it might be methane hydrate that triggers runaway deepwater convection, releasing all that greenhouse gas at once.

This seems to be a technology that responds to economies of scale.  Significantly lower pumping losses with larger pipes.    Some square/cube advantages in the turbines & pumps.

Many islands (Hawaii) burn oil for electricity.  (Cheap low quality oil for larger islands, diesel in smaller ones).  So the economics can change.

Add a pumped storage unit and wind, and a 100 MW unit MIGHT just "pencil out" at $70+ oil and eliminate oil use.

But how many islands in the tropics (that are close to deep cool water) need that much power ?  If one has to use 80 MW or larger units ?

Not many IMHO.

If small OTEC does not work economically (probable IMHO), and only larger units are economic, they have to be within 20 degrees of the equator and have a close in access to deep cold water, and they are only economic when compared to oil, then the world may not need more than 1,000 to 2,000 MW of OTEC.

Wind and batteries/load management may work better for many oil dependent islands.

Hawaii may be home to half or more of the feasible OTEC demand.

Reading some of the quoted references does not give you much confidence in the ability to use this technology for appreciable contribution to global electrical generation.

The literature is awash with grandiose schemes but actual achievements are modest. According to OTEC News the best to date produced 40kW of net power for 8 days. It produced a nominal 210kW gross power but most of that was used up driving the pumps. Under good conditions there was some net power, under poor conditions there was none.

This and the other problems and abandoned projects listed in that reference show the difficulty of working at energy conversion efficiencies of 3% or so. When your usable output  power is the small difference between huge input and waste rejection energies small changes in conditions can reduce your output to little or nothing. Corrosion, marine fouling, blocked filters, reduced dispersal of cold water at the surface and other practical problems can all destroy the small net benefit.

Extrapolating these projects to the size where they will have any effect on global electricity (10's of gigawatts or a million times the biggest so far) in the face of such precarious energy balance is uncertain to put it at its very mildest.

The energy returned to energy invested ratio is heavily dependant on the working life and maintenance requirements of vast flimsy structures in deep and often tempestuous seas. The thought of 11 metre diameter thin walled tubes a kilometre long in deep tropical water just to obtain 100kW net power seems just the sort of thing to cause running financial problems.

Although there are places where special conditions will probably make OTEC economic I have the greatest difficulty imagining a globally significant contribution from huge numbers of huge OTEC generators offshore in deep tropical waters to power needs in the existing centres of consumption.

Were OTEC to be developed on this scale the vast induced thermal churning of the oceans might have significant environmental effect.

If one believes the basic economics of taxation as: concentrating the benefits for a select few, and diffusing the costs to the unfortunate taxpayer collective, then OTEC has a viable future.  Huge taxdollar sums can be diverted to build these OTEC gensets with the future output only going to a select few living lavish energetic lifestyles.  PostPeak defending of OTEC installations anchored way off the continental shelves can be energetically done very cheaply.  At night, as seen from space, future America might be largely dark, except where the OTEC gensets power the baseload demand for the elite few [along with the remaining hydro and wind power sources].  Detritus Entropy rules: we should seek to match our population decrease to the Hubbert Depletion Rate to maximize energy/capita.

One possible way to increase the efficiency of OTEC gensets might be to harvest deep-sea frozen methane clathrates at the same time the cold, deep water is being sucked up.  I am not an engineer to know if this is feasible or not, but it seems the closer the intake tube is to the ocean floor, the less likely you are to suck up every variety of swimming lifeforms.  Just my two cents.

Bob Shaw in Phx,AZ  Are Humans Smarter than Yeast?

The most pertinent part of this interesting article is to be found at the very end - Our task would be easier if we could reverse Human Population pressures.

Low quality energy (i.e. low temperature differentials) are to found almost everywhere. The trick is to extract this energy without a monumental investment. At present, the most ambitious and extravagant way of extracting energy is through the use of offshore structure (e.g. Sakhalin). Does it make any sense to make much greater investments for far lower returns?</font>

The quality of energy can be improved, on land, by using concentrators for solar energy, for example. I know of no way of doing that with ocean currents.

Controlling population growth is a much more effective way of getting the necessary return. There are perhaps around one billion women on this planet would like to be able to access safe and convenient contraception.

Counting on a greater than 1 EPR this project should deserve the proper attention.

By the way, will it work during the less hot days of the year?

another possibility would be those tall tripod water reservoirs dotted around towns and cities perhaps?  

just a half baked idea