 Good afternoon. I'm Ethan Allen your host on likable science here on think tech Hawaii. Thanks for joining us this Friday afternoon We're gonna have another in-depth exploration of ocean and thermal energy conversion today We talked about that earlier this week on a different think tech show. I think tech talks Joining me today is co-host Ray Starling energy consultant energy guru and Dr. Hans Crock who is the world's world-own expert in okay ocean thermal energy conversion But before we do that I just I want to talk a little bit and do a little quick demo here about a very cool thing that I ran into today This week called Dot lens the group dot lens dot com they make these tiny little lenses and That you can very neatly put onto your telephone onto your camera your camera phone So you can drop Lenses that have it in place Usually stay right on that lens and then when you hit your camera setting This becomes Highly magnified right comes essentially wow a See the edge of the of the box there Yeah, anyhow, it's just a very simple very simple very low-key technology I thought it was a nice contrast with what we're talking about today in that this ocean thermal energy conversion in contrast is a very powerful technology with almost sort of earth-shaking possibilities and Just to get us started Let's talk a little bit about how sort of the underlying issue of how this works But then that it's got two temperatures of water you very cold water from deep in the ocean Several thousand feet down right and warm surface water and Those two streams of water heat Fluid in a clothe or fluid and gas in a closed system right something like a moan is typically used Mm-hmm, and the point is that the moan is liquid at the temperature of the cold water But in the gas at the temperature of the warm water, right? That's right, and so as you circulate it through the system with simple pumps You can turn it into a gas run turbines condense it back into a liquid Pop it up. Yes, it as I mentioned it's a heat engine Right, and and the heat engine has those particular elements in it And it's really not that mysterious because we're using heat engines to generate our electricity now the oil fired plant a coal fired plant are Heat engine you just use water as the working fluid and you use the fuel to boil the water and you use the steam to run the turbine and then you use the cold Cooling water to Liquify the steam again and run it around to the beginning. So it's a it's a heat engine and the deal with the Otec is that you're dealing with another Another range of temperatures there, so you have to use a different working fluid one that boils as you say at the temperature of the warm ocean water and it can Get back to a liquid form at the temperature of the cold ocean water so it's a matter of choosing the right working fluid and it happens that the working fluid that you use in an Otec plant is Essentially the same as a working fluid that we use in our refrigerators and Refrigerators are also a heat engine except in that particular case you're running it backwards you put the energy in and then you pick up the heat so to speak from the inside of your refrigerator and and you You compress that vapor to to make it Hot enough so that you can dump the heat into the cold source which is your room your kitchen back of your and so there it is and then you run it back around again and it takes up energy and because you're pumping things against its natural gradient, but in the in the heat engine for your producing power You take advantage of the natural gradient and then you run it forward so to speak and in fact, it's the same working fluid if you have a refrigeration system a large scale for instance and ice houses in large butcher systems it runs on ammonia and But you can use a regular refrigerant like you have in a refrigerator used to be free on but we don't do that anymore because of the Ozone hole problem, but still it's the same working fluid you could run an Otec plant on free on for example and your refrigeration unit or your cooler In your car or your house air conditioning system is in roughly the same range of temperatures as an Otec system so Again simple engines like that, you know, and you need a heat exchanger. You need a pump and You need a turbine and that's it, you know, so it's not that Otec runs on some sort of exotic technology that we don't know about and The deal with Otec is that it's big All right, and yeah, the beauty of Otec is that the heat source in this case is basically surface seawater Yes, which you've captured in essence Yeah, heat from the Sun and are you getting that off basically bleeding that excess heat off trying to get into electricity Yes, yeah, yeah turn it into electricity, but no no fossil fuels need to be burned No, no Things need to be mine Yeah, that's right. So so last Wednesday We didn't get to a Lot of what we would like to get to right today and maybe you have another session later But you know, we started talking about after the after the show about the fact that this In theory, this has been around for a long time It has it has grown and the technology has matured and We talked about the fact that that we're we're ready to go do something with this now and It it looks like that a lot of things are coming together And especially the climate change situation, which is a big deal That might that might accelerate this and actually make it happen and become real in in our lifetimes and If you could go back and talk a little bit about where we are today that I think that would be insightful and and help people to Understand that this is real Technology that we might be using sin. Yeah, well, it's a sort of a historical accident Because Otec was thought of before the internal combustion engine So and it was more or less a you know, I could economic accident that we discovered oil there in Pennsylvania and and Combined that with car development first many first cars were actually electrical cars, but and and That became our preferred pattern, but if we had followed electricity first and and used Used hydrogen because hydrogen was invented so to speak was discovered and a fuel cell was discovered in 1842 I believe or something like that and and if we had developed our transportation system with a hydrogen car, which is very simple again. It's a simply a Fuel cell and an electric motor And that's it. You know, it's and if we had done that and built a whole economy on hydrogen as a fuel or a direct electricity production from these sources then we wouldn't have an oil age, you know and suppose we did that and we came along now and we were happily going along in a hydrogen economy and Somebody would come along and say oh, let's let's dig up this oil And make internal combustion engines. Let's do that. Nobody would go that reaction You know and not only wouldn't it be economically we realize that oil is limited and that if you spill oil you have a problem if you spill hydrogen you don't really have a problem toxicity wise or otherwise and You run out You know, you will run out at some point and it's you have to fight other people for it You have wars and all kinds of things so nobody would go that direction if we had Hydrogen economy now so to me. I see that as sort of a hard interlude in the development of the earth You know It's a bit like what Gerard Diamond talks about in guns terms and steel It's sort of a weird accident of various factors that just led to this course of development instead of that course of development That's right. And if you look at sort of a historical You know say we go 200 years into the future and you go back and you say now there was a petroleum age it lasted for 200 years and You know then everybody saw the arrow of their ways and now we're back on track, you know and wasn't that a strange time? They fought wars and they had pollution and you know they they had global warming which we're just now getting over You know in the future talking about but that's really it, you know, that is a non-sustainable sustainable Way of getting energy and why is it so hard to change now because everything is built on And so you know we're used to it and we and like most things like that We can't conceive of not doing it that way because that's all we know But if you look at it from a more long-range perspective, it's really an aberration. It's not it's a it's a dead end inevitably well and and also we talked about you know, you you mentioned that the the temperatures are actually not that far that wide apart and so unlike Fossil engine where you've got huge Changes on nuclear or nuclear With with this you you mentioned that it needed to be big it needed to be Sized up so you're kind of trading the differential in temperature for volume So you pump a lot of volume through this thing and that's where that's where the problem is That's where the problem is because it costs a lot just to build something just to show that it it works It's simple, but it works This actually brought up a question when you mentioned that and I got to wondering what why is there a? Volume a size a scale issue. Why can't you build a tabletop? Sea water heat engine that would work well, right? Well, you can I mean like I say, it's a simple heat engine and you can just like you can have a little Little hydrogen generator that sits on you know on your lab desk, you know in every high school laboratory class probably, you know Makes hydrogen and shows it to the people and then blows it up or something, you know but so it it's it's a simple thing, but in terms of Powering a City or something like that that so a central power station. Yeah, and In the case of you know, why can't you do it in your house? Well, you can't do it because you don't have a cold source Okay And if you have a cold source, you don't have a hot Okay, we're gonna do this in Moscow, you know, well, you don't have a heat right it works well in the equator We're gonna we're gonna have to jump out and take a quick break right now Well, we'll be right back got Ethan Allen here with Ray Starling and dr. Hans croc talking about otak Hey, how you doing? Welcome to a bachi talk. My name is Andrew Lening. I'm your co-host and we have a nice program here every Friday at 1 o'clock think tech studios where we talk about technology and we have a little bit of fun with it So join us if you can. Thanks. Aloha Hi, I'm Stacy Hayashi with a think tech Hawaii show Stacy to the rescue Highlighting some of Hawaii's issues. You can catch it at think tech Hawaii on Mondays at 11 a.m. Aloha. See you then Aloha, I am Reg Baker and I am the host of business in Hawaii with Reg Baker We broadcast live every Thursday from 2 to 2 30 in the think tech studios in downtown, Alululu We highlight successful stories about businesses and individuals and learn their secrets to success I hope you can join us on our next show on Thursday at 2 o'clock until then Aloha And you're back here on likable science. I'm your host Ethan Allen here on think tech Hawaii With me today the think tech studio is dr. Munn's crock and Ray Starling We're talking about the Otec ocean thermal energy conversion and during the break our wonderful producer Zuri Ask a good question for Hans, which was well, what about the marine life of the fishes the corals the algae? How is all that affected by your Otec systems? We pull in the cold water out and dumping warm water back in and vice versa. Sure. Yeah, well What you're doing is pumping water around and so You In the entrance of your pump you want to like it like you would do in anything You would want to put a screen there to keep out, you know fish for example the small organisms the Algae Micra, you know phytoplankton and zooplankton and whatnot they go through heat exchanger for example generally there most of them make it through that's not a problem the the Organisms that you pull up from the deep ocean water You're taking the water from about a thousand meters down And if you look at the tropical zone that is in the area of the oxygen minimum You're way below any Lights light penetration, so you don't have any phytoplankton there to begin with you do have bacteria But relatively few and you have a very few Other macro organisms there because like I say that's at the oxygen minimum The ocean has fairly Actually quite good oxygen content for aerobic organisms fish and whatnot all macro organisms are aerobic and and but So they their oxygen there comes from exchange with the air and it also comes from Phytoplankton Producing oxygen in the surface there. That's all in the surface. That's on the surface That's and use as you go down some of the organic materials starts Falling down and the bacteria start eating that and using the ambient oxygen that that's around there And as it keeps on settling down there's they eat that up and they use up the oxygen and in in the course of things they There's a minimum in the in the depth and that happens around Depending where you are exactly, but 700 meters thousand meters That that level and you and this is where we Taking the cold water and that's where you have the minimum of fish life or You're not you're not taking this from the bottom and so you don't have benthic organisms You don't have crabs and whatnot wandering around there And so you just have mid-water organisms and they're generally trying to pass through the zone quickly because they can't breathe You know because they don't have enough oxygen. So still you'd want to put a screen on a pump for instance and that wasn't done incidentally in in the larger pipes that were Supplying the water at the natural energy laboratory of why and Kona and that set of pipes was fairly near the bottom because they are land-based and They had the same thought they said well, you know, I had the oxygen minimum Not gonna be very much many things here, but there were some, you know bottom-dwelling organisms and and some Ways, you know some sting rate like Wouldn't exactly sting rate, but raise like that and they came up the pipe and And they died and there were also some shrimp and whatnot. So I Died in the in the wet well so to speak because and so that was a little bit of a surprise to people but They can be easily screened. Yeah, you could do it a set of very very core screen finer screen Fine if you need to do that and in my particular design that I'm Proposing for the large floating plants is I would put the pump at the bottom Right, we talked a little bit at last week about this and the advantages of having your pump down at the bottom And yeah, that allows you to use a flexible pipe, right? Yes, exactly, and it's a lot cheaper and and With a modular construction It's within the range of things that we can build today And so this is a doable thing But the inlet the inlet to that pump Just like the inlet to the warm water pump at the surface you would put a screen right so you're so you exclude organisms and Those bacteria that would come up would Generally die You know because they are subject to pressure down there You release the pressure and a lot of them would lice Which means? And that that's particularly Obvious When when we were doing open cycle Otec because in that case you were actually subjecting the water to vacuum conditions So that even the warm water Bacteria would lice And that would mean that that discharge from the Otec plant basically For an open cycle Would kill the bacteria now That isn't a big problem because Because the bacteria when you put the Water back into the ocean You back basically have the building blocks all spread out for bacteria Because they and and then you day not the same ones, but they get rebuilt you know And bacteria life, you know isn't going to get wiped out You know Not with that price in any case Quick question, you know the When you're talking about free energy, which is what what Otec would be it's free the The fuel itself is comes from the Sun You don't worry too much about efficiency, but just for Thinking purposes what what how much do you have to make? in terms of Electricity to be able to to put to run a hot end of the system. Yes, yes Yes, and that that varies with size and that's one of the advantages of doing it in large Yeah, so in in our system that we're talking about where we have modules of 20 25 megawatt size As opposed to for instance the one megawatt Otec one ship or the the Otec the mini you Otec which was a few hundred Tens or a hundred kilowatts size, you know there the efficiency wasn't good, you know you would The efficiency in the sense that how much does it need to run your pumps and whatnot? What's the net amount there? it was We ended up getting I say we but the people doing at time because I wasn't on that barge Where You would only get like 50 kilowatts and you had Deal with 200 kilowatts at the beginning in your In the case the fuel is free. Yes, right, but yeah, I mean In a larger plant such as for instance what's shown here with a 20 25 megawatt There You get a net production of 85 percent. You only use 15 percent to run the entire system So that's very good. Yeah, that's you know, so and and they were the fossil fuel plant. Yes. Yes. Yes, right but a problem as an objection has been to with by people who say oh, this is this is inefficient So it's not Inefficient in the Carnot cycle, you know Well people who study these kinds of things people doing thermodynamics and whatnot, of course Carnot is It is a tool to evaluate things now the Carnot cycle efficiency assumes that That when you get through with things that you are at absolute zero. In other words, you're a hundred percent a Carnot efficiency would mean that you take every bit of the energy every bit of the heat out of your Working fluid or fluid that you're dealing with and you end up with absolute zero. Of course that never happens So the Carnot Efficiency is really the maximum that you can get Given the Delta T that you're dealing with in this case So it's the ratio of your available Delta T to the absolute zero temp. I mean Kelvin degree Temperature so it's it's it's a theoretical thing that we're not really talking about for instance the Carnot efficiency of a hurricane is the same as Carnot efficiency of Otec engine the Carnot efficiency of a of a wind mill is even less than the Carnot efficiency Of Otec plant, you know because there you're talking about, you know, how well what's What's the energy in the in downstream from the wind mill? You know relative to absolute zero where you have you know solid air behind, you know So to wrap silly sort of to wrap this up then you've got this technology that's available today There's nothing That really has to be developed new for it. No new materials. No new ideas in some sense You've got a technology that can Sort of borrow or use an existing heat source that's far in excess of what we ever could possibly use 10,000 times that essentially is non-polluting Indeed actually helps reduce the warming of the oceans and reduce the acidification of the oceans, too it does apparently minimal harm to any life in the ocean and produces Fresh water and electricity if you want that I mean hydrogen if you want to serve side products. Yes, so You're missing The fact that we're not doing it now and therefore we don't want to do it because that's it Yeah, well, that's that's what we I think we need to close on here is we all should get behind this This is really I mean it's really is a problem. They got you absolutely agree Yeah, I think we should be calling attention to our leaders about this as an option and really talking this up And I want to do so some more But we're out of time right now. So we're gonna have to talk somewhere later on I'm your host Ethan Allen. You've been here on likeable science Ray Starling and dr. Hans Crock. Thank you both for being here