Australia's renewable energy future
Tidal energy: A viable form of renewable energy
Tuesday, 7 July 2009
Dr Tim Finnigan
CEO and founder
BioPower Systems
Dr Finnigan, the CEO and Founder of Australian ocean energy company, BioPower Systems, has worked in ocean engineering for 17 years, holding industry and academic positions in commercialisation, research, and professional engineering in the United States, Canada and Australia. For the past nine years he has focused on ocean power conversion and the commercialisation of next generation technology to harness the renewable energy of tides and waves. Dr Finnigan holds a Bachelor of Applied Science in Engineering Physics, a Masters degree in Environmental Fluid Mechanics, and a PhD in Marine Engineering.
Tidal energy: A viable form of renewable energy
Chair (Mike Dopita): Good evening, everybody. I am delighted to see that the enthusiasm for these lectures has been carried through and worked up right to the very end of the series. It is not like some of the lectures that I used to go to at uni, where the numbers would fall away towards the end. It really shows the enthusiasm that we all have for renewable energy. It has been saddening to see how conventional thoughts produced by dirty greenhouse gas emitters on things like cap-n-trade systems seem to have seized our federal government and got them into their pocket in the same way as with the Liberal government.
In order to try to concentrate the minds of government, the Academy of Science is proposing to use its offices as an independent scientific organisation to produce a document that summarises what all of these speakers have been saying – including tonight’s speaker and the summary speaker – and put together a vision for Australia’s renewable energy future and the infrastructure that will be required, providing to government not policy directives, as it were, but policy options, just to give them the scope of what they could do if they really put their minds to it. By putting this document out into the arena of government and, more generally, business circles, we hope we can change the paradigms that we seem to be trapped in and which probably, if we continue with them, will lead to the demise of the Australian economy in the same way as General Motors went down. Failure to innovate is failure to survive.
We are going to have a final lecture on Tuesday, 4 August, from Dr John Wright, who is the Adviser for Sustainable Energy Partnerships in the CSIRO Energy Transformed Flagship. He will be talking about the contribution of renewables in Australia’s future energy mix. So I look forward to seeing you all next month at this lecture, which will provide a kind of a cap on and a summary of all these particular fields.
The other thing you should be aware of is that a public lecture will be given by the Academy of Science as part of National Science Week: Professor Michael Raupach will be speaking on Wednesday, 19 August. We do not have a title for that presentation, so look out for it to be advertised.
You will have seen from today’s Canberra Times that we have received quite good publicity on tonight’s speaker, Dr Tim Finnigan, the CEO and founder of BioPower Systems. Tonight he will talk to us about Tidal energy: A viable form of renewable energy. Dr Finnigan is the CEO and founder of Australia’s ocean energy company BioPower Systems. He has worked in this field for 17 years, holding industry and academic posts in commercialisation, research, and professional engineering in the United States, Canada and Australia. For the past nine years, he has been working in this particular field and on the commercialisation of next generation technology to harness the renewable energy of tides and waves. I ask you to welcome Dr Tim Finnigan for tonight’s lecture.
Tim Finnigan: Thanks for that kind introduction and thanks to everybody for coming out tonight to listen to this. Just to extend on the enthusiasm that has been mentioned, tonight I will talk to you about some Australian technology that is very exciting. Despite my accent, I am an Australian trying to promote an Australian technology. I have been an Australian for quite some time, but I am still working on becoming an Aussie. I think there are two different things there. One day I will try to sit through an entire cricket match and maybe that will give me the credentials to be an actual Aussie – but it is more of a formality just to become officially Australian.
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Ocean energy is a viable form of renewable energy, I think, in the very near-term future for us in Australia. I will talk to you about some of the science behind it and some of the ways that we measure and monitor it, just to convey to you that it is real and it is an abundant resource. Then I will talk about some of the final steps we need to get through to make it commercial so that you will see it on the market and producing power.
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As an overview, I will go through some of the renewable energy drivers – I think with this audience I can keep that pretty short, as you will know what is driving this industry and what the issues are out there – and then I will introduce ocean energy. The title of my presentation mentions ‘tidal energy’. I will speak a little about wave energy as well as tidal energy, of course, and the commercialisation of ocean energy. How do we get the technologies that are emerging in this area out of the labs and out of the pilot and prototype stage and fully functioning in a commercial environment?
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One of the steps in that process is pilot projects. I will talk to you about some of the work that I am directly involved in and that our company is working on with pilot projects and then I will talk about the next step, so there is a bridge between pilot projects and the commercial stage. I will talk about what some of the requirements are for bridging that final gap and then I will talk about the future opportunities that we are all looking forward to.
Drivers: looking at the uptake or the demand for electricity, it is our fastest-growing energy requirement; energy goes into other uses, of course, but the fastest-growing demand on our energy needs into the future is for electricity. It is expected to roughly double over the next 20 years. Globally, we are sitting at about 18 trillion kilowatt-hours of electricity production and we are looking for that to double over the next 20 years.
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Where is that going to come from? If you look at the energy reserves in fossil fuels, they are running out, and some of the world’s major energy-using countries are running very short on their domestic reserves. You can see there India, China, Russia, the UK and the USA, which arguably are some of the biggest power consumers. Looking at numbers of years, you will see that those countries, apart from Russia, have less than 10 years of oil reserves left. So that energy has to be developed from somewhere.
The obvious other driver that you are all aware of is the climate change issue. I am not even going to go into that. I think I am preaching to the converted for the most part on that issue. That is a major front-page issue for all of us and I think it is a given in this case. I am talking here more about energy security and energy supply.
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Fossil fuel energy has to come from somewhere to supply those countries. If you look at the percentages of global reserves remaining, the biggest bars on that graph represent the Middle East and North Africa. They are typically unstable, which causes issues for global trade, price and all kinds of other issues. Putting climate change to one side, just the pure supply of energy into the future will drive the uptake of renewables. One of the key benefits of renewable energy is that it is distributed and it is local: it is close to the sink, so you generate that energy near to where you use it.
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Ocean energy: what is it? It is the extraction of useful energy from the coastal ocean, as the title suggests, and that comes primarily from waves and tides. I will go through the motion of waves in quite some detail: how that energy is created and manifested and how we look to tap it. Tides: the modern way of using tidal energy is to tap into the stream. You may be aware of tidal dams or barrages, which is technology from the past. It is ecologically unacceptable in today’s world to build a barrage across an estuary, so that type of tidal system we do not think will ever be built again. I will talk to you about the modern way of approaching tidal energy.
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Let’s start with wave energy. If you look at the spectrum of wave periods in the ocean, it goes from the very small, the tiny capillary waves on the surface, right out to the very, very long waves or the tides. The tide actually propagates around the world in the form of a wave, but most of the energy contained in the wave spectrum in the ocean is generated by wind. These are normal waves that we all know, propagating to shore on our coastlines. The big bump in this picture, which contains most of the energy, represents waves with a period of between about one and, say, 20 seconds. I will get into the definition, but the period is just the time between successive wave crests or how long it takes each successive wave crest to come by.
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How is it generated? Surface waves are caused by wind. The wind blows over the surface, creating a friction that drags some of the water forward so that it becomes unstable and produces wave motion. The longer the wind blows, the more energy is absorbed at the surface – and, the further along it blows, the bigger the waves get. You have capillary waves way down at the centimetre wavelength and the wavelength grows longer. Gravity waves are the longer waves. Eventually, as wave height increases, waves start to break.
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If you measure the up-and-down motion of a wave, you will have a profile similar to the one you see at the top – this is just to define some terminology so that you will understand what I mean by ‘wave height’. Wave height is the distance between the crest and the trough, and the wavelength is the distance between successive crests. The top line is called a regular wave; it is of a very uniform, constant frequency and typically is not what you see in the ocean. The bottom line is a real irregular wave profile. You can see that both the wave height and the period vary. The term there labelled ‘HS’ is the significant wave height. That is a measure of the mean of the highest one-third of the waves. That is the common measure that we take when we are trying to characterise a wave field to measure the energy; it is sort of an average.
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At the source where waves are created, this is what the sea state looks like. The waves that we look to tap into for energy come from distant storms in the Southern Ocean, the North Pacific and the North Atlantic, where there is very fierce wind that is consistent and blows very hard for a long time. That puts a lot of energy from the wind into the surface waters of the ocean and you get a really mixed and messy sea state, with lots of different frequencies and wavelengths travelling in all different directions. That is very difficult to deal with. We do not try to tap energy from this source, but we rely on the process that happens as the waves propagate.
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There are a couple of little equations in here for any scientists or engineers in the crowd. They are very simple and are just to convey how wave energy works. Phase velocity is the speed that the waves travel at and cp is the term that we use for phase velocity. This is simply the wavelength divided by the period: the length of the wave divided by the time between successive crests. That tells you how fast the waves are moving; it is the speed at which the waves travel.
The group velocity is the speed at which the energy travels, so it is the speed at which the wave packets travel. That happens to be half the phase velocity. This picture [bottom panel on slide] demonstrates how it works. Think of individual waves travelling across the surface of the ocean. They do not live very long: each individual wave has a short life span. It emerges at the back end of a wave packet, grows to a peak height and then disappears at the front. These wave groups or wave packets travel across the ocean. This is all part of the physics of wave propagation. You can see the dotted envelopes here progressing along. The actual waves within them are moving twice as fast as those packets. This is an important concept: the energy propagating across the ocean does not move at the wave speed; it moves at half that speed. That is important for us in understanding how fast the energy is arriving at the coast when we want to tap into it.
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Let me clarify one little point on the difference between power and energy, as sometimes there is some confusion there. Energy is conservative. It is measured in a quantity called a joule; that is the unit of energy. It cannot be created or destroyed. It can be converted, transferred and propagated, but you cannot actually destroy energy. Power is the amount of energy delivered over a period of time. It is the amount of energy in joules divided by, say, seconds, and the amount of energy in one second is called a watt.
The usual measure of electric power – I am talking about power now – is in kilowatts or megawatts. Everyone knows that those terms represent power. Those two terms are often confused, but energy and power are two distinctly different quantities. The usual measure of electric energy is in kilowatt-hours. That is what we pay for on our power bills: the amount of kilowatt-hours. If you run a 100-watt light bulb for an hour, you would have 100 watt-hours of energy use. There is just that little difference. When you are thinking about the difference between power and energy, that is the difference.
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Back to wave propagation and energy – and this is the last of the equations. I will hit you with all the hard bits at the beginning and then, as we go along, we will get into the more comforting side of it. This is energy, represented by E, in a horizontal square metre of sea surface. If, while looking down at the ocean, we draw a map of one square metre, given the wave height ‘H’, we can understand how much energy is contained in that piece of ocean. The symbols ρg and 8 there are constants and are not important. We know the group velocity, the speed at which the energy is travelling, so we can measure the power. The power is just the energy being transferred at the group velocity. So we can measure the power by combining these first two relationships. This is just a function of some constant here, multiplied by the wave period and the wave height. That is just a simple message that the energy contained in the waves coming at us depends on how big the waves are, their height, and the time between successive crests, which is how fast they are coming in. That tells us very, very accurately how much power is available.
For example, if you have ocean waves with a 10-second period – a pretty typical wave period for the ocean is 10 seconds between wave crests – and a wave height of two metres happening all the time on our coasts here and you plug those two numbers into that power equation, you get an answer of 40 kilowatts for every metre of wave. Let me just explain that. If you are standing on the beach, looking out at the ocean and waves are coming in with a 10-second period and a two-metre wave height – very typical conditions in Victoria, South Australia and Western Australia – every metre of wave crests that you are looking at is constantly delivering 40 kilowatts of power into the shore. What is happening to that power? It is dissipating and getting lost, as it goes into all the foam, turbulence and noise that is being created when the waves break, or it is going into eroding the sand and the cliffs. We are looking to capture some of that, obviously.
Forty kilowatts is not a huge amount of power but, if you find a way to grab several metres across one of those crests, you can multiply that. If you took, say, 40 meters of that, you would have a capture of up to 1.6 megawatts, and now you are talking about real serious utility-scale power. Wind turbines, we know, typically are about a megawatt scale. So, if we can create a system or a device that can grab 40 meters of power at some reasonable efficiency, we can expect to deliver megawatt-scale power per device from waves. It becomes a very compelling and interesting area, and it is what has held the interest of a lot of people around the world for a long time. I think now, as I have said, we are getting close to bringing it to reality.
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The other thing we rely on is just the shape and the form of the waves. I have shown you a picture of storm conditions, and that is a very difficult wave environment to deal with. Typically, those waves are generated, say, a thousand kilometres away, deep in the Southern Ocean, where we have extreme storms. When we deploy wave energy converters around our coast, we are looking for better conditions. I can show you here that the group velocity is, in another equation, directly proportional to the wavelength. This is the term for the wavelength. That tells us that the longer the waves, the faster the energy travels.
This little picture just shows you a demonstration of that. Assume that machine moving up and down is a storm [Animation – device on left moves up and down and waves propagate across to right demonstrating the dispersion principle], churning up the ocean and creating a whole bunch of different frequencies and different wavelengths. It so happens, from the physics of wave propagation, due to this equation, the longer ones move faster and come out the front. You can see here the nice clean, long waves emerging out the front, leaving the mess behind. A beautiful thing about wave propagation is that it isolates different wave frequencies and effectively it cleans up the wave field. So the further away the storm is, the better for us, because what we see at the receiving end is a very clean, regular wave field that we can start to work with.
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How do we start to characterise and measure these things? A bunch of different diagnostic tools is available for us to understand the available energy from waves in the ocean. Some of them are remote-sensing techniques, such as synthetic aperture radar or altimetry radar, and then we have the in situ or in-place direct measurement methods, such as wave buoys and ADCPs (acoustic Doppler current profiler). I will go through these now.
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Aperture radar looks down and gives you a signal of the wave field from a distance, so you can create maps from it.
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Radar altimetry is another method; we actually have global maps of wave height from this technique. It is important here to look at the relative size of the waves down below Australia. The Southern Ocean there, due to the Roaring 40s and all the energy being pumped into the surface waters, is an incredible engine for creating wave energy. Waves will travel thousands of kilometres with almost zero loss of energy. The propagation physics that I just went through is extremely efficient; it just conveys that energy across the surface of the ocean with very little loss. So we are sitting on the doorstep of a massive energy resource.
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We can put devices, such as wave buoys, in the sea that monitor this. As we have these scattered around Australia, we can hone in on a point-by-point basis and get an even more accurate measure of the available resource. We have records in several places around Australia that date back decades, so we have a statistical measure of the available wave energy around the country. Many other countries have a very similar set-up.
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These ADCPs are what we use directly in our company. ADCP stands for acoustic Doppler current profiler. That is a device that you install on the seabed. It has an acoustic signal that pings up to the surface and it measures reflection off all the particles in the water column. It also has a pressure sensor that measures the surface motion. With this, you can pick up a continuous record of the wave motion at the surface and the particle motion or the velocity motion below the surface. It gives you a very comprehensive, detailed picture of the wave climate at the specific location you are looking at. When we pick a site that we are interested in, perhaps testing for wave energy, we put one of these in for a year or so and we get a very clear picture of the energy available there. The same kinds of techniques that wind power and solar power use we are now using in the ocean to look at this resource.
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An ADCP is a small device. It sits on the seabed. That picture shows a diver with an ADCP. It is deployed and you leave it there. It ticks away for months on end. When you go back – hopefully it has not leaked or had failed batteries or something like that – you will get some data that you can then go away and work with.
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There are also global models, which are a fantastic resource or tool that can be used. I know that a lot of work has been done here at the Australian National University on this type of area – CSIRO has been very active as well – measuring or modelling with computers the wave resource globally or regionally; they feed in wind data and measure the propagation of waves. This is what the Bureau of Meteorology uses for forecasts, measuring the wave climate.
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You can see here the wave height again, measured as ‘significant wave height’ as a sort of average. It tells us where the waves are coming from, how big they are and when they are expected to arrive. So one of the benefits of wave energy is its predictability. You can forecast wave energy far further out than wind. We know when there is a Southern Ocean storm a long distance away. Given the simple equations that I have shown you, we can understand exactly how long it will take for that to arrive on our shore – five, six or seven days ahead. This helps with wave energy conversion for forecasting to match grid demands. With the way the open market works with electricity uptake, the more time you can give ahead, they can start to work with the futures and better incorporate wave energy into the electricity market.
Focusing in much closer, there are more-detailed physics models with computers and they can show us very detailed information on the wave characteristics at a specific site. I will come back to this site, which is the southern half of King Island in Tasmania. We are quite interested in the wave climate there and we are working on a project there. We had this modelling done to tell us: ‘Well, we know all the general wave conditions further out in the deeper water, but we want to know how it varies in fine detail along the coast so we that can pinpoint the best spot to deploy some technology.’ These computer maps can tell us that.
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So the tools are all there. The technology is very well developed for monitoring, understanding, measuring and characterising the wave energy climate in the ocean. That work has been done. We can say that it is very mature and we understand the resource. Typically, what you get from all the statistical analysis and the information that you gather is a wave climatology chart or a scatter table. This tells you, for a particular site, the combination of wave periods and wave heights that you might expect. It gives you a clear map of conditions at a particular site. You can then tune your device or your method of taking up some of that power according to the varying conditions there. It would be no different from the wind records that you get at a wind energy site; this is the way wave energy is characterised. So there is very well-developed science behind this.
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If you do that all around the world – this is generated from computer charts – you can build up a global annual wave power atlas; that is what is shown here. It tells you that same measure of kilowatts per metre. Remember standing on the beach looking out at a one-metre width of waves coming at you? If you sat there for a whole year, not moving and measuring it constantly and then took the average across that whole year, these are the types of records that you would see.
Red is greater than 60 kilowatts per metre. Remember that I gave an example of 40 being a pretty good measure? Sixty is exceptional. Typically, the red dots are in the high latitudes. Western Europe is pretty good. Look all along the southern coasts: Chile, South Africa and a huge resource all the way across southern Australia. New Zealand has a good opportunity as well. Looking at maps like this, we can truly say that, in terms of wave energy, Australia has a world-class resource along much of its coastline.
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I have talked about forecasting and using these models. You can pull these charts down off the website of the Bureau of Meteorology on a daily basis. I had a look at that on Sunday, 5 July, and saw that a swell pattern was moving from the south up the east coast of Australia.
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I was in Sydney, so I took a walk down to Tamarama and, sure enough, there was a nice swell moving in, just as the charts had predicted. That demonstrates that you can read a forecast map driven by a computer model and you can very reliably expect those conditions to turn up on your shoreline – or, hopefully, on your power plant. The dispersion effect is working very well here: nice clean, long crests and not a lot of mixed, messy seas. They are beautiful conditions for surfing or for wave energy extraction. So that dispersion-and-frequency separating effect that I mentioned truly works and here is the proof.
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I have talked about wave energy: what it is, how we measure it and how we know there is a viable resource out there. The next problem is how we capture some of that energy. Typically, we have to put a machine in the ocean to do it. With wave energy conversion or a wave energy converter – sometimes we use the acronym WEC – you start with the input, which is the wave energy impacting on the device. You somehow have to convert that energy into stored energy or directly into a mechanical energy. Often what is done is that motion or some sort of reaction of a device is used to pressurise a fluid and that fluid is then used to drive a turbine. The turbine then spins an electric generator and out the end comes electricity. So inside a wave energy converter you have these steps taking energy across different stages. It is converting the energy and losing a little bit across each step, which is where the efficiency comes in. There is a challenge in that a lot of the developers of these technologies are trying to move from their top line to a simpler system, where you take energy through a very direct conversion into electricity and then into power; so that is moving from motion straight into electricity. That is a little trickier, given the timings of these devices.
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Let’s look at some examples of how this is done. I will not go into detail about all of them, but there are a number of different methods with different names. An attenuator is a floating device that attenuates or absorbs energy as it is flowing past. There is the obvious way of putting a buoy-like device on the surface; it can be submerged. You can have devices where the waves come over the top and then drain through a hydraulic turbine to generate power, or you can have devices that sit on the bottom and pitch back and forth with the waves. There is a whole array of different methods for putting devices in the ocean to catch this source of power. One you may have seen before is an oscillating water column where the motion in a chamber drives air across a turbine.
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Here are some examples of what I regard as first-generation wave energy converters. They are mostly oscillating water columns. These are some examples that have been built in different places through the eighties and nineties. This one in Scotland never quite made it, as it was destroyed or damaged on the way out. The history of wave energy conversion is littered with these kinds of problems. It is a very difficult environment to work in, and a lot of partial successes met with huge failures throughout its history.
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But we have moved on. Here are some of the other buoy-type devices from the past.
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Over the last decade a whole new range of devices and different techniques have emerged, all taken from that list of examples. Oceanlinx is a Sydney company that developed an oscillating water column, which is shown there. I used to spend some time working on that one as well.
CETO is a buoy device, also an Australian technology, and Pelamis is a European one that has been trialled. So there is a whole range of different methods for doing this, including Aquabuoy and other buoy-type systems.
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The approach we are using at BioPower Systems is a pitching device. As a submerged oscillating device, it fits into the whole gamut of different wave energy devices. So, if you characterise all the different methods, one issue with wave energy is that it has not yet consolidated like wind turbines have. There is still a whole range of different methods and we are looking for a winner or a couple of winners out of these. Ours sits down here. It is called bioWAVE and is a submerged pitching device. I will not go through all of these, as there is a whole range.
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The bioWAVE technology that I am working on is an oscillating device that is completely submerged. The reason it has ‘bio’ in its name is that it is drawing from biomimicry and it is modelled somewhat on the motion of sea plants beneath the waves. What we were looking for here was a device that does not try to fight against the forces of the ocean but moves with them. This is a 25-metre animation model, so it is not a small device. It would produce 250 kilowatts. It simply oscillates back and forth. Inspiration from nature has really given us clues on how to take some of the structure or weight out of the device to make it cheaper. So it moves with the forces and does not try to fight the big waves.
The real key here is that, when you do get the very rare extreme events, such as the massive storms with the really destructive waves, this device picks up a signal that that kind of condition is occurring and simply descends to the seabed and lies flat so that all that extreme energy goes over the top. We do not have to engineer to withstand those extreme forces but simply let them go; it takes cost out of the device. When those conditions subside, up it comes – this is all automated – and it resumes operating. So we give away a very tiny percentage of the time with extreme waves but save a lot on the engineering costs.
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Here is how that works. If you look at a wave energy converter, the unit cost of power or the cost of generating that energy goes up with the design wave height. If you are building a big structure on the surface, you have to design it to withstand the worst condition you are ever going to see, which could be a 10-, 15- or 18-metre wave. That will destroy the system unless it is engineered well. So, typically, you design for that condition way out at the biggest range of waves. They rarely occur; if you overlay a frequency of recurrence, they very rarely occur. The waves that we want to generate power from – what we call the ‘money waves’ – sit in this intermediate band and occur quite frequently. Our approach is to design only up to the top end of that operating range and that translates to a direct cost advantage. So, from a commercial perspective, this is where we see the bioWAVE having an edge on some of the other technologies and giving us an opportunity hopefully to come in and compete against other renewables.
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The system is comprised of a base and a pivot that allows it to rotate into the waves. All the generators are contained in a steel module, and we have some simple structures of lightweight fibreglass that catch the power and move back and forth. So the generator and all the equipment is on-board and completely sealed, and it delivers power ashore.
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We are doing a lot of testing on this: wave tanks in small-scale models and measuring the power output and the response in different wave conditions. That is just an example and it was done at the University of Tasmania.
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There are different variations of blade shape and different spacings. The arrangement that you see there with multiple blades is optimised for energy absorption. It allows the system to absorb as much power as is possible from a pivoting-type device.
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Wave energy is one side of ocean energy and I will talk now about tidal. You will all be aware that tides are generated by the moon rotating the Earth, pulling on the ocean. When that force is released as the moon rotates around, the tide propagates as a very long wave.
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That wave propagation is repeatable; it is always happening and it always occurs in the same way. So we have a very clear map of the tidal motions in the ocean; they can be predicted decades in advance. You will see that it is localised. There are nodes where there is no tide and the waves are propagating around these zones; there is no vertical motion in those locations. Where it is red, you have a strong tidal motion. So tidal energy is focused in certain areas. You can see that there is a little bit in Australia, a little bit in New Zealand and some big patches in different areas around the world.
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As I just mentioned, these are caused by the moon. These tidal motions, where they impact on topography, generate currents. It is from those currents that we are looking to tap some power.
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This is a picture of a tidal current in Tasmania at an undisclosed location. You can see that directly from the tides there is a very strong flow. Every cubic metre of water weighs about a tonne. So, when you get that motion and that much mass moving, you are looking at a massive amount of power being propagated. We want to put something in that stream to take some of that power out and use it for electricity generation.
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Again we are looking at the measurement of this. The reason I am talking about measurement is that I want to convey to you that it is not just a resource out there and waves or tides that we think might be viable; it has been well measured and well documented and it is a significant resource.
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These are measurements that we, ourselves, have done directly. This is the current speed across one day. The tide shifts and every six hours it changes direction. It rises up to a peak, goes back to zero, rises up to a peak and goes back to zero. So it changes direction, but it is very regular and very predictable.
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If you look over 1½ months, you can see it rising up and down every day. It is modulated over fortnightly periods, so you get stronger and weaker tides – there are strong peaks here – and the dots indicate the direction, so it is flipping direction back and forth every day as well. These are just examples of direct measurements.
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We can also measure the local structure. On the spot, we can measure the vertical distribution of the current speed and, because of the bottom drag, it is a bit stronger towards the surface. So we have a very well-characterised resource in tides as well.
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Computer models: all the same things applying to wave measurement apply to tide. The CSIRO did this piece of work for us at a site we were looking at. Looking at the flow speed with the tide propagating back and forth through a channel in Tasmania helped us to find the best spot to deploy a tidal device.
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You can get very detailed information from this. Now we are looking at a cross-section. In the vertical it shows a slice that enables us to understand what the flow speed variation is, as well as in the horizontal and across time. That is a lot of information.
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Power is much simpler when looking at tides than when looking at waves. If you have a flow with the speed of U passing through an area of A, the power is a simple equation that goes up with the flow speed cubed. So every little bit of extra flow speed that you can find has a massive impact on the power; it is a cube relationship. That makes it very important to do all this modelling to find the best spot to put it, because even a tiny bit more flow speed translates into significantly more power.
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This has been done through computer models and measurements. Here is a picture of Bass Strait. The yellow and the red bits that you can see are where there is a stronger available tidal power. Obviously, we have been interested in Tasmania because there are some dark red parts around there that we think have the potential for tapping.
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Tidal converters: very quickly, here is a dam-type tidal energy converter [top left of slide] with vertical axis turbines. You can put a rotor in there. It has a bit of an impact on the environment. The other way to do it is with a simple wind turbine type device that is lowered into the tidal current [bottom left]. That is a pilot system in Scotland. Sometimes you put a duct around the turbine to channel the flow a little bit. This ducted one is a Canadian technology [bottom right].
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Here our approach, biomimicry, was employed again. It is different from a turbine. You can recognise straight away the biological influence on this one. It is an oscillating device that would be 24 metres long with a 17-metre high fin, so again it is a sizeable structure. All the generating equipment is inside this capsule and we have a computer controlled rear fin pivot, so we are optimising the angle of attack and maximising the absorption of power by driving this arm against a generator that is on board the system. As for the benefits of this one, again it is lightweight. When we have excessive currents, we can allow it simply to streamline: it turns off and just weathervanes. It is very light on the environment because it is slow moving and has a smooth surface. There are no spinning rotor blades or sharp parts that could impact any marine species. It is just another fish in the sea, really.
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The anatomy of this tidal system that we call bioSTREAM: again we have to have a foundation or a base to hold it in place and to fix it against those strong currents and keep it there. It has a docking mechanism. I will show you in a moment how the base is put down first and then the unit is docked on top. All the generator equipment is in a sealed module. Again it has a lightweight tail structure and an actively controlled biomimetic hydrofoil. We have measured benefits from the shape characteristics of that hydrofoil. There is a reason why fish – shark, tuna and mackerel – have a specific outline to their fin shape. It has been optimised over billions of years to be very, very efficient. We’re simply copying some of those traits in this technology to benefit from the efficiency.
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We are testing these devices and are currently developing a pilot system of 250 kilowatts at Flinders Island.
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Zooming in on Tasmania, you can find one of these perfect little tidal channels where the currents are accelerated through a constriction. We have measured the flow there and done the computer modelling, so we know how the currents flow through these channels and we are looking for where the topography accelerates that flow.
We move in a bioSTREAM and sink it into place. This is all underway and planned for deployment next year.
We run a cable to Flinders Island, erect a small substation on the shore, extend the on-land cable into the existing grid – and, voila, we have power on Flinders Island. They already have power there, but it is diesel-fired, which is very expensive and very dirty power. They would like to tap some of the resource sitting on their doorstep to supply the island.
We are working with Hydro Tasmania on this project. We are supplying all the equipment and doing the installation, and they are helping us to facilitate connection into their distribution grid. This is scheduled for deployment in the first half of next year.
250 kilowatts will supply about 200 homes. We are working also with Siemens and Bosch Rexroth, putting the best equipment possible in that module so that it is reliable and functions well.
Inside this unit is state-of-the-art equipment. It will be commissioned next year and we will test it for one year.
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How do we actually get the thing in place? We have modelled even that process. You have to consider in the design how you transport it, deploy it, sink it, fix it and retrieve it – how you do all the steps. This is a picture of a simple vessel towing out the foundation. [ANIMATION – vessel tows foundation into place and foundation is lowered onto the seabed] We have come up with a design that does not rely on a lot of special vessels. I will probably have to cut this short because it does go on for a while. Air is released from the foundation so that it sinks under its own weight – we have some buoys there to steady it – and it is simply dropped into place in the seabed. I will move on to the next sequence, in the interests of time.
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This shows a similar process. [Animation – bioSTREAM device towed into place and installed]
The unit has a cable, which you can see faintly, looped down through a pulley. When the ship’s winch is wound up, it pulls the device in against its own buoyancy and down on to that docking mechanism. So there is a simple two-step process to deploying these units. I will move ahead.
It has all the real wave motion and physics there, so we understand the conditions when we are going about this deployment.
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The anatomy of the sensors: we will pack this thing with every sensor that you can dream of so that we can measure all the different responses: vibrations, power output and speeds. Everything you can think of is transmitted through a fibre optic line within the power cable and, sitting in our office or anywhere else, we are able to monitor the system in real time.
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Returning to King Island and wave power: we have a pilot project going with bioWAVE there as well. Again we have modelled the wave conditions.
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The idea there is to bring in our bioWAVE, sink it into place off the west coast of King Island – this is a sister project to the tidal pilot – cable ashore to a shore-based substation, have a small grid connection, and power into King Island. Again we are working with Hydro Tasmania. So we have a two-technology double-resource approach to our development.
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There is a similar suite of sensors on the bioWAVE.
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Our vision is to move beyond pilots. We will scale up the device so that each puts out one megawatt. Of course, we hope that in a few years we will be deploying these in farms, as you see here [referring to slide], and have larger scale 40-, 50- up to 100-megawatt scale farms feeding directly into the national grid so that we can really start to provide some significant power and offset some emissions.
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I think these are all playing into the needs of pending renewable energy targets and the goals that are being set by Australia. Both systems, tidal and wave, can be deployed as farms.
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The real issue now is to get the cost down. If you look at the cost curve, we are sitting up at the high-cost end with our pilots. The first commercial demonstration, which will be of single units, will still be quite costly. We need to rely on grants and feed-in tariffs to offset some of those initial high costs – the difference between the actual cost and what is commercial. It has to be partly funded by investors and they want a return. We need a subsidy of some sort to offset it. This is the common way, which was used with wind and solar around the world, to bring new technologies on-line. As we move down, we give away the grants, feed-in tariffs and renewable energy credits. They are very important incentives to make an industry like this work. We have seen it in solar in Germany and Spain – and in Denmark, which really brought wind energy to the world.
If we can deploy it, and get through that process down the learning curve, it will be stand-alone commercial, competing head to head with wind and other traditional sources.
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In summary, the application of biomimicry in these technologies has given us a method of engineering lightweight designs. We have two technologies, one for wave and another for tidal, that are overcoming some of the barriers to commercialisation. Also, these lightweight systems are having a low impact on the environment.
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I hope that I have demonstrated that Australia has an abundant wave and tidal resource. It is often located near load centres. It can be more predictable than wind. It has zero emissions. There is a global resource out there. So, while we can look at Australia’s interests in deployment and developing an industry where we can benefit from jobs and economic development, there is actually a global resource out there. Perhaps we could come up with something like a Vestas or a GE Turbine type company in Australia, as Denmark did with wind.
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Again, the advantages of this technology are that it is lightweight, has smooth surfaces, has a small footprint and is efficient.
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This is an Australian technology and is based in Sydney. All the patents are Australian owned and protected around the world. We are looking to complete these pilots and looking for commercial opportunities in the near term in Australia and overseas.
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I will wind up there. If you would like more information on this technology, you can look at our website. I hope I have convinced you that there is a resource out there and a technology that is really coming near to a commercial frame. We are very excited about what lies ahead in the next few years. Thank you.
Discussion
Chair (Mike Dopita): Thank you very much, Tim. That was a great talk. I am going to declare the floor open for questions. Please put your hands up. We have a couple of runners who will bring microphones around and I will try to keep those two people going simultaneously. Perhaps I may use my chairman’s privilege. You had a cost curve, but you did not have any numbers on the vertical axis.
Tim Finnigan: That’s proprietary information.
Mike Dopita: But, seriously, what kinds of energy costs are we talking per kilowatt-hour in, say, 2014?
Tim Finnigan: We are looking to bring generation costs for both technologies to under 10c a kilowatt-hour in the 2014–15 range. To give you an indication of the target, that equates to installation costs of about $2.5 million per megawatt and, depending on market conditions, that is under 10 cents per kilowatt-hour. Wind operates at about 8 to 10 cents, so we would be looking to compete directly with wind, possibly even slightly better, in that time frame.
Question: How do you overcome the problem of marine growth fouling of these devices?
Tim Finnigan: Marine growth will occur on the device. There are different ways to address that. There are environmentally benign coatings, which can inhibit it. Submarine growth we do not see as a problem and it varies from site to site. It will be worse in some places and less of a problem in others. The bioWAVE will have a fluid boundary layer on the surface. Some extra roughness will not affect the performance. It will not look too good, but you don’t see these anyway, as they are beneath the sea. It is a matter that we will monitor, but we do not see it as a major issue.
Question: Well done, Tim. We will need dispatchable power in the future. With the 100-megawatt system that you are contemplating, for a nominal power rating – out of modelling and knowing what the sea does – what would be the lowest output that you could expect and where would you cut it off maximum-wise? What is dispatchable, truly?
Tim Finnigan: It differs between wave and tidal. Looking at wave first, it will depend on the site. There are sites around South Australia where you would almost never have to turn it off. It would kick in at a wave height of about half a metre. If you measured the waves in Victoria or South Australia, I think you would be hard pressed to find a day with less than half a meter; more typically, it would be well over a metre or two metres. But for a few days per year, even in those good sites, you simply would not have enough power to operate. The capacity factor for wave that we are predicting from our models is about 40 per cent. So, if you have a 100-megawatt wave farm, on average, across the whole year, it would output 400 kilowatts. With tidal, we think it is slightly higher, possibly closer to 500. That is because the tide is always there. It is off for a short period four times a day, but every day it is there. There is never a day without a tide, because it is run by the moon.
Question: Obviously your company has done a lot of research on the optimal locations for tidal. How does your company go about securing the rights for those locations? Also, is there anything stopping other companies from coming into those same areas and implementing devices – not only the physical characteristics but also close to the grid et cetera?
Tim Finnigan: That is a challenging area. I have to say that there is a lot of grey area out there. So obviously, because of that issue, we are keeping quite confidential some of the sites that we are looking at. Legislation for taking up marine-energy leases or seabed leases is being put in place in some Australian states, but it is not quite there yet. So, when we approach some of the states to look at a possible site, we get sort of channeled through a myriad of bureaucracy from one place to the next, trying to work out what permit we need, what lease we need and who to talk to for this and that.
Question: That would be harder than finding the actual site itself.
Tim Finigan: It is. You can find the site easily with the models. They will tell you, ‘That’s the site.’ You actually need a permit if you are going to get a diver to go there; we found that out. You can dive there but not for commercial purposes. You get into trouble for that, if you are looking to prospect on the site. But, yes, we think that legislation is coming. There is a process now whereby you can apply to Crown lands, depending on which state you are in, for use of a seabed for a certain length of time. But the interest in developing it is way ahead of the legislation that will allow it. It is not a simple matter.
Question: What is the life span of these devices? Also, do you know what the greenhouse manufacturing cost of it is?
Tim Finnigan: We know. I do not have the number with me right now, but we have done whole-of-life-cycle analysis on our systems to measure or predict the greenhouse gas emissions that are part of its production, including the materials. We offset that against the emissions that it saves when it is in production. Its life span on a commercial scale is about 25 years. The life of the pilot device I showed there is much shorter; it has a five-year life and initially it will run for only one year. But we have modelled the whole-of-life- cycle: the amount of emissions caused by making it and the amount saved by running it. We have the information, but I do not know whether I would be able to share it with you in any case.
Question: What about it coexisting with shipping? Are there issues with that sort of thing?
Tim Finnigan: Yes. There are competing use issues with shipping, recreational use, the fishing industry and environmental impacts. With any project we look at, even with our pilots, we have to take a very thorough and carefully planned approach to dealing with those competing uses. For example, with the two Tasmanian islands, we spent a lot of time there consulting with the community, making everyone aware of what we were planning to do, fielding their enquiries and trying to be sensitive to their needs. When there is shipping, we have to find a region that is away from shipping channels, because you could not have shipping lines through these, at least for the moment. So it would be cordoned off with buoys and would be a no-go area.
Question: You are talking about this as a pilot. How much work has been done, other than modelling, on the actual deployment of test elements like this in the ocean to see how they perform when deployed in ocean currents? I guess I am asking: how early is the technology in terms of the pilot?
Tim Finnigan: Specifically our technologies, the bioWAVE, or just in general?
Question: Your technologies in particular. But, just in general, are there other technologies that are further advanced?
Tim Finnigan: Yes. Wave energy is nothing new, really. The first wave energy device patented was lodged in France in 1780-something, so people have been looking out at the sea and wondering how to capture power for a long time. There are thousands of wave energy patents and probably about 30 technologies around the world being developed; maybe 10 of them have been piloted. So there are devices – I have shown some pictures of them – that have been deployed in the ocean. Very few have been grid connected and run for any length of time. There have been trials but, as I have mentioned, they have always met with some fraught issues or problems before too long.
Our pilot device is under construction now. The generator module, which I talk about, we have built in a factory in Sydney for both devices. It is about to be commissioned and tested under dry-testing conditions, with power into the grid and extracting from the grid. The rest of the device construction and foundations will be carried out over the next six to eight months, and we hope to have both of those installed next year.
Question: And really that will be the first deployment into the ocean?
Tim Finnigan: Of our systems, yes.
Question: Do you see any scope for storage of ocean energy, such as the manufacture of hydrogen for fuel cells and so on?
Tim Finnigan: Yes, I certainly think it is important and probably more so with tidal because, as you are aware, unfortunately the tide basically stops at certain times of the day. Unless you have a lot of other stability in the grid, it would be good to store some of that. Also, the time the tide is running is not always matched with the demand. So storing with hydrogen or battery storage is important and it could be useful. It is not a focus of what we are developing, but we do look at that option.
Question: Some of the attributes that you describe particularly for tidal energy can be found also in rivers, irrigation channels and even perhaps sewage lines. Do you see any future for some of these concepts in inland areas?
Tim Finnigan: Yes, I certainly do. Some of the turbine concepts are possibly more suited to it than our technology. In our modelling and doing all the economic development and economic predictions behind ours, we have found the simple result: bigger is better. I will not bother you with another equation, but again there is an equation that shows the gains you get in power output as you make the device bigger are nonlinear. So, the bigger you get, the more bang you get for your buck. So, while we are piloting at 250 kilowatts, we know that we have to go to a megawatt per device and then possibly to two megawatts. So, with these larger devices – and it is because of this natural curve – you would get more power out for less dollars in. It is similar to a wind approach.
Question: I think we have good evidence now from earlier lectures that other renewable forms can make a strategic contribution to the national power requirement. I guess my question is: is it your vision that this type of technology could make a strategic contribution to the national power demand at some time in the future?
Tim Finnigan: Absolutely. The title of my talk refers to ‘tidal’, but I know that as part of this series another wave energy lecture was given by a former colleague of mine, Tom Dennis; I worked with him previously as well. But, if we are talking specifically about Australia and its wave resource, that resource is massive. There are literally thousands of megawatts available there. That is not to say that technically we do not have challenges, as it is a very difficult environment to work in. However, because of our ability to lay that system down, we are approaching a solution to having something that might actually survive out there. That has been the problem with wave energy – mostly survivability and reliability. That is because at times the ocean throws everything at you and it does not matter what you do. You would not try to beat it; you have to try to get away from it. But, if we can overcome those last few steps, I think there is definitely a significant input for Australia particularly from waves. With tidal, there are definitely good spots in Australia, but it is a little more site specific.
Question: You have said that you would have a bunch of sensors to check on pressure and so forth so that you can make sure that your machines stay safe. Have you thought about putting in other sensors for temperature and salinity and things like that also so that we can gather some data over the 25 years that they will be sitting under the water?
Tim Finnigan: Yes, we could put those on for a fee.
Question: Have you modelled the number of humans that would be needed to work with each plant?
Tim Finnigan: Are you talking about jobs?
Question: Yes.
Tim Finnigan: We have some rough modelling. Just to make you aware: we have already planned in some detail 240-megawatt commercial developments for Australia. They would be our first commercial-scale projects and they will follow the pilots. For us the pilots will be next year, 2010, and they will start in 2011. Pending funding, we will start to deploy in Australia two 40-megawatt projects; I will not give you the details of where and how. But all of these systems, should they be developed and built in Australia. Everything, including the R&D and engineering, would be manufactured in Australia. So it is in the hundreds of jobs. We think for a 140-megawatt plant there would be probably 300 new jobs and, for the 25-year length of the operation, about 50 jobs continuously. So it is quite an interesting opportunity.
Mike Dopita: I think the issue of jobs in the renewable sector is very cogent to acceptance by government of renewable energy sources. We see the coal industry complaining that the imposition of a carbon cap-n-trade system in Australia will cost Australia 30,000 jobs. From hearing all of these lectures, my feeling is that a lot more jobs – a lot more-interesting jobs than just digging holes in the ground – are available in the renewable area. I would like you all to thank Tim for what has been a very interesting and fascinating presentation.
I hope to see you all here next month to get a final overview on this whole lecture series. Richard Bray assures me that he is already planning the next lecture series on the general topic of water. So I look forward to seeing you all next year as well. Thank you.
