Any body of water when it is warmed by the sun at the surface will tend to separate itself into thermocline gradients. The sharply defined layers prevents the mixing of the waters inside them. This leads to a leaching of nutrients needed for plant growth and so by mid spring in places like the north sea primary biological production has for the most part stopped. Deep Ocean Water (DOW), where these nutrients abound, represents 99% of the volume of the ocean and are just out of the reach of marine plants, separated by a thin skin. This is why the tropical oceans are crystal clear. There are almost no microscopic plants (micro algae) in the water to turn it green.

That is not to say that that the potential of seaweed isn’t huge. A company called Bio Architecture Lab based in Berkeley California has perfected an enzyme and process which liberates the sugar from alginate. This single substance represents 30% of the dry mass of seaweed. BAL’s method has an 80% efficiency rate of the theoretical yield. This is a huge advance and by their figures the harvesting of seaweed from 3% of costal waters would generate 60 billion gallons of biofuel.

The Tidal Irrigation and Electrical System opens up large areas of coastal ocean to macroscopic algae cultivation that would not normally grow commercially harvestable amounts of seaweed.  It does this by using tidal forces to syphon DOW into a lagoon where it is isolated from the surrounding ocean and creates a large bioreactor. It does this while producing food and gigawatts of electricity. (Please see the links on the right of this page for further details of the products of the system)

The new increase in efficiency in the processing of seaweed by BOL will result in a huge gain in production for the TIE System. The two technologies are made for one another.

There is, however, a whole different set of problems created by having an excess of CO2 in the air. This is about how the atmosphere and the oceans interact to create carbolic acid and is known as ocean acidification. I blogged about it here. The long and the short of it is that as the ocean becomes more acidic, corals and some planktons find it harder and harder to grow until they die off. As the effect increases, the whole oceanic food web breaks down. The major geologic models we have eventually resulted in extinction events, the largest of which killed off 95% of  the life in the ocean. We are a long way off of that but even a slight change can have remarkably deleterious effects on the ocean’s ability to produce food. Some of the latest horrifying figures can be found in this article, which details a report from the UN and this one about a model of surface uptake.

One biologist, Ronald Osinga, presented an interesting idea at a symposium involving the growing of sea lettuce (ulva lactuca) to combat the acidification of the ocean.  Roelof Kleis wrote an article about the symposium which was held at Wageningen, the Netherlands by the International Society for Reef Studies (ISRS). It had an emphasis on climate change and the deleterious effects it will have on coral reefs. Presented on the last day, Osinga pointed out the pollution caused by current fish farming techniques could be utilised to grow sea weeds for human consumption or for food for fish.

Osinga and his colleagues have calculated that a ‘marine garden’ of 180,000 square kilometres could provide enough protein for the entire world population. A sea lettuce bed of such gigantic proportions would raise the pH (acidity level) of the Mediterranean Sea by one tenth. That may not seem much, but according to Osinga, it would be enough to compensate for the rise in acidity that started with the industrial revolution.

My criticism of the scheme is that it fails to account for the eventual nutrient loss if either the fish or the sea lettuce are taken from the system for consumption by humans. This aside, the proposal does have huge implications for the Tidal Irrigation and Electrical System (TIE System), the subject of this blog. One of the key components of a TIE System is its ability to deliver the nutrients necessary to a lagoon isolated from the surrounding ocean, in order to create a sustainable aquaculture. It does this while producing electrical power.

The TIE System is driven by tidal action and so it is difficult to estimate the amount of power generated by Osinga’s 180,000 square kilometre figure. But, if there was a tidal swing average of 2.33 meters and each TIE System had a diameter of 20 kilometres, the 573 aqua farms should produce about 36.3 TeraWatt Hours every flux. This is on top of producing the sea weeds necessary to change the pH of the oceans to offset the consequences of fossil fuel use AND feed the whole population of the world.

It is worth noting that 36.3 TeraWatt hours per flux is about 23,849 TeraWatt hours per year. In 2007 world consumption of electricity was 17,109.7 TeraWatt hours. The economic and societal imperative to develop the Tidal Irrigation and Electrical System seems to become increasingly evident as time passes.

According to the US Department of Energy it represents 4.6% of domestic fuel consumption and less than 1% of electricity production. Unfortunately, these numbers are misleading, as we all know, most of the things in the US that are made of plastic are made outside the country. The ubiquitous child’s toy originates in China. This distortion of public information is employed by most governments around the world. It is safe to assume that when factoring in the imported shipping and manufacturing of plastics the amount of petroleum used is much higher than official numbers.

The low value source material biomass that forms the feed stock for the pyrolitic bio-oils used by the Amherst team are creating high value olefins and aromatics like benzene, toluene and xylene in a high yield process. To achieve this they use a variable-reaction hydrogenation phase and this is followed by zeolite catalyst step. Zeolite is commonly used in kitty litter but it has many other uses. Check out the abstract for Renewable Chemical Commodity Feedstocks from Integrated Integrated Catalytic Processing Pyrolysis Oils. The company Anellotech has the licence.

As useful as this is the issue remains of sourcing the water and fertilisers that are needed to grow the biomass in the first place. (please see my previous blog Water and Soil – not just Oil) The nutrients that are represented by the plants themselves must be replaced in order for the soils to remain capable of growing quality vegetation but even more fundamentally, world wide, droughts and water profligacy has lead to ever more energy consumption in the quest to get water to agricultural land.

The fixing of nutrients into a usable form is an integral part of the biomass potential of the Tidal Irrigation and Electrical System. It does this without consuming fresh water or the need for petrochemical fertilisers. Check out the flash based demo.

The technology for creating stable off shore islands has been developed for the luxury home market in Dubai. The World and Palm projects have proven that stability is just a matter of engineering. The adaptation of the island creating technology to generating, food, fuel, electricity and fertiliser should be a small matter.

On another matter, one of the main concerns for the walls and the overall structure is that of tropical depressions (cyclones, typhoons and hurricanes) and tsunami. Any potential realisation of a TIE System will experience forces many thousands of times stronger in extreme events than it will face during normal day to day operations. Like any other structure, an architect will need to make a decision about how robust to make the structure versus what is the frequency of the event and the effects of the destruction of the structure on the surrounding environment. In the case of a TIE System the type and frequency of these hyper-events is dictated by the location of construction. However, it should be noted that in all tropical depressions the ocean itself rises around 10 meters. This could be used to a TIE System’s advantage. By keeping the profile low to the tidal maximum’s mark, once submerged, the TIE System’s structure would be protected from the most damaging waves and extreme tidal streams.

The other factor in the equation; the effect of a breach of a TIE System should be minimal. Certainly, if not returned to the nutrient rich deep oceanic water (DOW), any macroscopic algae will die off after a couple of weeks. Depending on what animals are being grown in the lagoon some will die. The vast majority of the life in the lagoon will probably be eaten by the animals living around the TIE System. Once the system is running again, by seeding the DOW with the desired species (and other methods of mariculture) normal production can resume.

The last thing to consider in this forum about extreme events on the walls of the lagoon of a TIE System is that a failure of one part of the structure will not lead to a failure of another part. If the pressure builds to any point on the walls to where it bursts, this will instantly start a tidal stream that will completely release the pressure that allows the overall system to work. It should only fail in one spot and that should be relatively easy to fix.

This is a major oversight by the EBI because of the limitations of municipal waste as source material for fertilising algae or “co-product”, as it refers to it. The first major obstacle for any open pond using municipal waste is the availability of flat ground on which to build the ponds. The EBI estimates that 1000 acres would be needed to break even economically. That is a huge area for any city to acquire. Most flat land close to big cities was long ago used for houses.  The second major obstical to using municpal waste as the source material for algae is due to its limitted potential. Despite the vastness of the world wide human populations only about half of us live in what could be described as cities and it will be a long time before any significant proportion of those people will have sewage systems capable of being converted to biofuel making.

Most importantly there are two conceptual failures of the EBI’s report best illustrated by a couple of metaphors; No animal can live on it’s own waste and you do not collect rain with a thousand cups, you collect rain by building a dam in the valley. Our waste simply is not sufficient to power our industry, no more so than any animal could live on it’s own waste and as most of our food is ultimately derived by turning fossil fuels into fertilisers or by pumping fresh water for irrigation, this means we are recouping some by turning municipal waste into feed for algae but it will not replace the ultimate source material, the fossil fuels. The rain metaphor is more to the point of looking at the nutrient cycle from a macro-scale as opposed to the micro-scale. From the point of view of the earth a single city no matter how big is still fairly small. On the big scale nutrients generally move from continental interiors down rivers to the sea or are blown to the oceans in the form of dust storms. In the oceans the nutrients sink in to the deep and there they remain until they are eventually recycled in the form of mountains built as a result of subduction. Of course, there are countless eddies in this nutrient flow where plants utilise them and these take form in the shape of a blade of grass, a sandwich, a swamp, a forests, a single cell of blue green algae, the polar oceans in spring, deep ocean water upwellings, etc., but these are merely slowing down points in the long term trend.

The largest reservoir of free nutients for plant growth on the planet are the deep oceans. The ocean below the direct influence of light is unbelievably vast and it is the perfect medium for biofuel growth. It is the closest thing there is on earth to a limitless resource. The Tidal Irrigation and Electrical System harnesses the tidal flux on the surface to pump DOW, deep ocean water, into a thermodynamic exchange in order to generate electricity and then it is held in the tidal barrage as the source material for algae growth (please see the sections on how the TIE System works on the right side of this page or http://demo.seavac.org/ for a flash based audio/visual tour of the project) This gets around the two major issues of land based ponds that are fertilised by municipal waste. Being built on the continental shelf the TIE System does not require the all too scarce flat land and the potential for scaling up to meet the huge demand is also possible.

By not paying attention to the large scale issues of the nutrient cycle the EBI has focussed on expensive and ultimately limited biofuel systems. DOW based systems are a much better bet.

There are advantages to both systems but now a detailed analysis by Anna Stephenson at the University of cambridge has compared them and found that open air ponds are 16.8 times more efficient than perspex tubing (Energy and Fuels, DOI: 10.1021/ef1003123). In an article published in the New Scientist, it is pointed out that pumping through plastic tubes results in a higher energy cost per unit than traditionally sourced fossil diesel. However, this is not the case for open air ponds.

As Ms. Stephenson says, the major drawback to open air ponds is evaporation. So much water can be needed that ponds in many countries would be in direct conflict with traditional demands for water, if they want to produce enough biofuel to replace their domestic consumption. This is not an issue for the Tidal Irrigation and Electrical system because it does not use fresh water, it uses the ocean. Also, the tidal flux is being harnessed in a TIE System to do the pumping and deep ocean water is used as the both the fertilizer and source water for the open air pond, making it much more efficient than the land based ponds envisioned by Ms. Stephenson.

Of course, the potential for the use of fish-to-biodiesel for the Tidal Irrigation and Electrical System is huge. The introduction of filter feeding species could lead to a much greater energy capture for the entire system then by the sole utilization of macroscopic algae like kelp.

This does however create the nightmare scenario of giving every marine animal a monetary value as fuel. In the future will there be fishing mafias that strip entire ecosystems? Will the seas be subject to even further unsustainable practices in order to fuel our cars? The oceans already suffer from the tragedy of common ownership. The collapse is imminent in the majority of the world’s fisheries. This technology could inadvertently push them over the edge.

As to the specifics of how the report dealt with the Tidal Irrigation and Electrical System; to put it simply it didn’t. It generalized all systems which utilize deep ocean water (DOW) into one broad category and in that category they only looked at the potential to transport CO2 from the atmosphere to the seabed. This is a great shame because systems which exploit DOW produce power and biomass on large scales. The Tidal Irrigation and Electrical System is the first renewable energy system which has proposed trying to capture the biomass component of the OTEC process. The utilization of these biomass resources can lead to less fossil fuel use and this is because they go into everything from fertilizer to food to plastic to the lights in our city’s and the fuel in our cars. However, this does mean that the biomass generated is not being stored on the sea floor so by the logic of the report it did not do much to offset climate change in that manner.

One idea that the Royal Society is interested in that this author feels desereves special derision is that of “artificial trees”. In proposal, these man made structures would litter our planet by the million. Their sole job is that of absorbing CO2 from the air. They produce nothing and rely on energy intensive processes in their construction and in either the storing of CO2 or the manufacture of the chemicals which are used to absorb the gas. The same problems that face other mechanical or chemical storage methods for capturing atmospheric carbon such as the ones that are proposed for coal burning power stations. A further criticism of artificial trees is that there is only a small economy of scale in the in industrial processes which underpin the concept. None of the designs become more efficient as they grow in scale. It does make this author wonder if it wouldn’t be better to build wind turbines in everyplace they are thinking of constructing one of these things. That might mean that the carbon emitted by the burning of fossil fuels was never released into the atmosphere in the first place.

Recently, I submitted the TIE System for assessment by the Royal Society’s working group on geoengineering schemes to mitigate climate change. (http://royalsociety.org/news.asp?id=8085) In the process I have been looking at a few other ideas. Many of them, like increasing the albedo of marine stratocumulus clouds and shading the earth with a large group of small spacecraft at the inner Lagrange point (L1), totally fail to deal with the issues that simply having more carbon dioxide in the air will create.

Ocean acidification is caused by the upper layers of the ocean taking up CO2 directly and by the changed air currents increasing the weathering of rocks. It seems that previous models have underestimated the sensitivity of the oceans to increased CO2 and acidification can increase much quicker than thought. (http://www.physorg.com/news148227653.html)

This is bad news for these geoengineering schemes that fail to deal with the excess CO2 in the air. One of the most pervasive mass extinctions in the history of the earth was caused, it is thought, by ocean acidification. Massive volcanic releases of CO2 caused the end Permian mass extinction  as acid turned the oceans toxic. (This theory is well explained at http://www.uwm.edu/~mfraiser/pdf’s/Bottjer.et.al.2008.pdf ) Thus the oceans went from a greenhouse gas sink to a greenhouse gas emitter as anaerobic conditions caused wide scale release of methane and Sulfur Dioxide. Global temperature ended up near 35 degrees C. That is rather eye watering considering that 2007 had a global temperature of 15.04 degrees C.

Already a fifth of the world’s coral reefs have died and we could lose most of those remaining in the next 20 to 40 years according to the Global Coral Reef Monitoring Network. (http://www.physorg.com/news148116950.html) This is due to temperature rise and acidification and will destroy the livelihoods of an estimated half a billion people who depend on coral reefs, unfortunately this may be only the beginning.

It seems the list of side effects due to our use of fossil fuels grows longer by the day. We must bring our carbon use into balance or who knows, we may wind up at the end of the Permian again.