The Tidal Irrigation and Electrical System

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. 

The concept of peak oil does not only encompass the end of cheap fuel for transport, it also spells the end of cheap food and water. 

By the late 18th century, minds were already turning to the problems of too many mouths to feed given the agricultural technology of the time. Malthusian predictions of population crash and civil disorder due to our inability to produce food faster than our population grows have emerged with a fair degree of regularity ever since. We have developed new strains of crops and this plays a part in meeting our need for food, but this is tiny compared to the new technologies that supply water and nutrients to the plants and those that transport the food to the populace at large before it rots.  Thankfully the final components in plant growth i.e. sun light, appropriate temperature fluctuation and atmospheric composition, have never been an issue for modern humanity to face. The technological developments have been varied: some simple, like crop rotation and the mining and applying to the land of ancient deposits of bat guano, and some industrial, like freezing, pumping, mechanization and chemical fertilizer.  

Despite the advances of plant breeding and the development of genetic modification, the reality is that increasingly, we have relied on techniques which are energy intensive to produce the food on which all live - and energy generally means fossil fuels. There is a wonderful letter in the New Scientist that illustrates the problem:

Peak soil 25 June 2008

John Chambers, Banbury, Oxfordshire, UK

William Stanton observed that, as oil is needed to work the farm machinery and natural gas is needed to produce the synthetic fertiliser used in grain production, the phenomena of “peak oil” and “peak gas” will inevitably lead to “peak grain” (31 May, p 23). The amounts of energy involved are indeed huge: it takes at least 35 megajoules to produce each kilogram of nitrogen in synthetic fertilisers, and 80 million tonnes of such fertiliser is used globally each year.

There are, however, yet more risks to grain production: 70 per cent of the world’s water use is in the irrigation of arable land. About 1000 tonnes of water is required to produce 1 tonne of grain. Much of this is drawn from underground aquifers - and these are close to depletion in parts of central Asia, the Middle East, north Africa, India, Pakistan and the US. Drill holes in excess of 1 kilometre deep are not uncommon, but to lift 1000 tonnes of water over that distance requires at least 9.8 gigajoules.

Grain is grown in soil, but 65 per cent of all soil on Earth shows signs of degradation such as erosion, desertification or salinisation. Over 300 million hectares of former agricultural land is now too degraded to produce food, and a further 10 million hectares become degraded or damaged every year.

“Peak soil” is long gone.

From issue 2662 of New Scientist magazine, 25 June 2008, page 24.

Biofuels grown on the land are not the solution. When factoring in the total energy that we consume in the agricultural process, biofuels generally fail to be worth the effort; you lose more energy than create and of course the water problem can only partially be fixed by pouring more energy into extracting it from the ocean or the ground. Even the use of the waste from crops for biofuels should be carefully considered before large scale implementation. The issue is about the nutrients that are represented by the waste being taken away from the soil. Traditionally crop waste is left to rot or to be eaten by animals which break down the plants for return to the soil and use by the following crop. As it is, this system is liable to exhaust the soil eventually. The nutrients that are locked up in the food we consume are removed and not returned to the land. Biofuels using crop waste will only exacerbate the problem by removing the nutrients represented in the form of stalks and leaves for use as fuel. 

The only solution is to find a new way to generate fertilizer. The Tidal Irrigation and Electrical System can do this by bringing deep ocean water (DOW) into its lagoon. The water in the deep ocean contains the vast majority of decomposed bodies of all the things that ever lived on the land or in the sea. It is the perfect medium for plant growth, and were it not for the salt we could spray it directly onto our crop lands and expect phenomenal growth. Kelp makes an excellent fertilizer and has been used for many centuries and grows, like all marine plants, extremely quickly in the presence of DOW. (See Algae/Marine Plants) 

There is a wonderful example of a natural process which moves DOW from the ocean to high up into the mountains where it fertilizes an entire forest ecosystem. Certain ocean currents and winter brings DOW to the surface in the pacific northwest and consequently marine plants bloom and these plants go on to feed the animals. Salmon sit near the top of the food chain in that part of the ocean and as such each one of them represents a large concentration of nutrients like iron and nitrogen. As they move up the rivers into the mountains to spawn they are heavily preyed and scavenged upon. The eagles, bears and vultures move on to their respective wider territories which extend for hundreds of square miles beyond the river. There they spread manure (which is fertilizer) far and wide. Eventually they die and their bodies are scavenged spreading the nutrients even farther across the Rockies. 

The TIE System can create the source material for fertilizer on a vast industrial scale as well as help alleviate some of the fresh water problems we are facing. A product of the OTEC subsystem is thousands of gallons of fresh water. Pipes made cold by DOW condense water out of the atmosphere when exposed to tropical air. The TIE System does all this without aggravating the problems of land-based agriculture. 

Researchers at the Helmholtz Association of German Research Centres and Caltec have successfully captured syntrophic microorganisms. These creatures consume methane and normally live in the anaerobic conditions in marine sediments existing in complex microbial ecosystems. It has been very difficult to separate the individual Archaea that were responsible for the anaerobic oxidation of methane because they do this in symbiosis with sulphate-reducing bacteria. Some estimate that 80% of the methane in the ocean is consumed by these microorganisms. Now that these organisms and their genes can be studied in isolation this may lead to new ways to combat methane pollution, something that all forms of agriculture and aquaculture lead to. The work has been published in the current issue of the renowned Journal Proceedings of the National Academy of Sciences and the method of extraction was patented (Pernthaler A, Orphan VJ (2007) US Patent 11/746,374).

Also, studies of Coal Oil Point conducted by Susan Mau at the University of California at Santa Barbara indicate that only one percent of the methane released into the ocean makes it into the atmosphere. Coal Oil Point, a huge and well studied natural methane seep on the bottom of the sea off the coast of Santa Barbara, releases about two million cubic feet of methane a day. By using data from 79 surface stations, they studied the plume of released gas in an area that covered 280 square kilometers. Full results will be published as the cover story in Volume 34 of Geophysical Research Letters.

David Valentine, associate professor of Earth Science at UC Santa Barbara, hypothesized that the methane is oxidized by microbial activity in the ocean. Although there was no attempt to capture or culture said microbes, there is little other explanation for the destruction of the methane. 

Microbial agents will be vital for minimizing the generation of methane due to the increased biological activity as DOW is brought to the surface by the Tidal Irrigation and Electrical System. The research above shows just how effective these microbes can be.

Tags: Methane

One method of lowering atmospheric carbon dioxide through the growing of algae in the ocean is by adding powdered iron to the surface. The iron acts as a fertilizer and the algae that blooms absorbs the carbon dioxide in the building of its tissues. However, the consequences of sudden jolts of nutrients due to fertilizer being washed out of the soil are severe. In the Gulf of Mexico these conditions lead to dead zones and red tides, which kill off millions of fish. Because of this I have always been skeptical about the uncontained release of nutrients into the open ocean. This is due to the fact that anaerobic conditions don’t switch on - they build up. Meanwhile masses of methane is produced. Classic OTEC designs at least are releasing DOW which is in perfect balance for producing normal healthy algae. The iron seeding programs seemed very counter-intuitive to me. Normal, healthy plants need more than one nutrient and they would have sudden jolts of biomass growth followed by nearly complete die-offs.

The New Scientist reports in its June 12th 2008 issue that it now seems the UN Convention on Biological Diversity also has deep concerns about the process and has banned it until more research has been done. At the same time Mary Silver of the University of California, Santa Cruz has presented her findings to the American Geophysical Union in Fort Lauderdale, Florida. She has results that indicate that iron encourages the growth of particular algal populations that produce domoic acid - a potent neurotoxin. Domoic acid can sicken or kill animals and people who eat contaminated shellfish.

Hopefully this will encourage those who see the potential in marine algal growth schemes to look more closely at the full life cycle of what they produce and to instead consider the TIE System. The TIE System uses DOW, which is the ideal fertilizer for algae, and it contains the biomass so the open ocean isn’t shocked and methane pollution can be limited.

Tags: algae, carbon dioxide reduction, dead zone, Iron Seeding, red tides

A durable and relatively inexpensive way to filter water from oils and bio-contaminants has been invented by researchers at MIT. These mats can be recycled and are very hydrophobic. According to the university it can absorb 20 times its weight in oil.

“What we found is that we can make ‘paper’ from an interwoven mesh of nanowires that is able to selectively absorb hydrophobic liquids–oil-like liquids–from water,” said Francesco Stellacci, an associate professor in the Department of Materials Science and Engineering and leader of the work.

Made of potassium manganese oxide, the nanowires are stable at high temperatures. As a result, oil within a loaded membrane can be removed by heating above the boiling point of oil. The oil evaporates, and can be condensed back into a liquid. The membrane–and oil–can be used again.

This is problematic for any potential large scale use in a TIE System unless the energy intensive extraction method can be incorporated into the bio-petroleum conversion process. However, this is an important technology for cleaning up oil spills and other environmental contamination.

For the last several months I have had a series of constructive conversations with Dr. Chris J C H Watkins about the TIE System and I intend to write more about these discussions later. One piece of information in particular has caught my imagination; “Enhancing Electrical Supply by Pumped Storage in Tidal Lagoons” by Dr. David J. C. MacKay. Nicknamed by Dr. Watkins as over-pumping, the principle behind the idea comes from the fact that the amount of energy able to be extracted from a tidal barrage is increased by the square of the flux. So in a hypothetical tidal barrage that produced one megawatt for a one meter tidal flux, if the flux increased to two meters it would produce four megawatts - or if the tidal flux was increased to three meters the same tidal lagoon would produce nine megawatts. Of course, this is a gross simplification of the principle.

Pumping enough water to make this worthwhile involves having the mechanical means to do it and the available excess energy to invest in the system. The technical hurdles are hard to underestimate as in a tidal lagoon of the scale of a proposed TIE System, it involves moving thousands of cubic meters of water per second. Also, the cost of artificial atoll walls are generally considered to be to the square of the height.  This means that careful analysis will need to be made of any potential site to see if the energy needed to invest in the system is available. If it isn’t then it makes no sense to build the additional height in to the atoll walls as the ocean water will not be pumped in. Dr. MacKay’s document points out that energy from wind turbines and even the national grid can be used for the purpose of pumping water in to or out of a lagoon to increase the output from a tidal source because the return of the investment is to the square of the cost and also that many tides are less than the natural tidal maximum. This is an ideal use for excess electrical capacity: for example during a windy night when the electricity generated by wind turbines would otherwise go to waste it can be used to pump water into or out of a tidal barrage and this potential energy can be released when the demand increases.

Dr. MacKay points out that it can also be used to a greater extent on the low ebb of the tide by pumping additional water out of the lagoon. The advantage of low tide over-pumping over high tide over-pumping is that in the high tide scenario the tidal barrage needs to be built to the height that one intends to store the water whereas in a low tide scenario no additional build cost is incurred.  

Over-pumping adds another layer of complexity to the cost benefit analysis of any Tidal Irrigation and Electrical System’s proposed location. Dr. MacKay has envisioned that this form of tidal barrage is connected directly to an electricity grid and so generates AC power. In my mind, this remains an open question as to the cost effectiveness of this use of the power. (see Electricity Infrastructure) Also, as the amount of energy generated by the OTEC subsystem compared to the simple tidal flow through turbines is so much greater in the OTEC and the amount of interference between the systems (see hydro) is an unknown, this is another area worth investigating. Nevertheless, this presents many intriguing possibilities and increases the flexibility and potential output of the TIE System. 

One question that springs to mind is; under what conditions would it be worthwhile to turn the OTEC system from passively siphoning deep ocean water to actively pumping it into the artificial atoll? Also, as the OTEC uses 2 parts warm to one part cold water what would be the effect of dumping the warm water component in to the lagoon as well? The OTEC’s efficiency would rapidly decrease but would this be offset by the increased efficiency due to over-pumping? To what degree?

Tags: hydroelectric, over-pumping, tidal

Sharp is claiming to have achieved a new record in direct methanol fuel cell power output of .3W/cc. This is very good. The power consumption needs of all sort of devices can be met by that. The general loss of energy by using electricity to recharge a lithium-ion battery relative to the amount of methanol needed to power, say, a mobile phone is huge. Around 80% of the potential energy is lost due to heat by a lithium-ion recharge if you calculate from original source material i.e. a coal power station. Whereas methanol could be shipped as easily as alcohol losing maybe 10% of the potential energy in the fuel it takes to get it distributed.

It says in the press release that it was achieved by “microfabricating” the stack structure. These processes are notoriously difficult to “scale up”. There is little detail as to the cost of manufacture so we shall see. The Fuel Cells site has lots to say about methanol in fuel cells.

Methanol is a potential product of the Tidal Irrigation and Electrical System’s biomass. (see Algae/Marine Plants)

Tags: bio-mass