| 497 Main Road
Tasmania 7010 Australia
Phone: 61 3 62497868 (am)
Phone: 61 3 62713000 (pm)
Fax: 61 3 62730010
Printed in cyberspace on recycled electrons
Keeping you informed about TecEco sustainability projects. Issue 69, July 29th, 2007
This article addresses environmental, commercial and technical reasons for the take up of Gaia Engineering and TecEco technology. All three are related. I could have just provided a series of claims without scientific support as I am often asked to. Personally I don't think that good enough so every claims is explained and supported by the science and where relevant appropriate references in the detail that supports the following summary..
Humankind have built with everything from dung to mud, metal to timber, grass to gravel, plastic to cardboard. There is hardly a material that has not been tried and used throughout the millennia. Building with man made carbonate and wastes should not therefore faze corporations and governments desperate for a quick fix to the global warming and waste problems. On the contrary TecEco bio/geomimicry solves the problems of global warming, water and waste and should excite industry as all are new markets in the sense that they represent new materials and methods paradigms. Gaia Engineering is simply the most exciting, brilliant and necessary technology on the planet right now. What is more, compared to so called clean coal or nuclear there are no downsides.
Portland cement when hydrated is an unstable binder as amply described in the literature yet we persist with the archaic formulation first developed by Smeaton, Aspidin and others. TecEco explain that in Tec-cement concretes, their formulation for pre-mix, the lime should not only be removed by the pozzolanic reaction but replaced by highly reactive magnesia with low lattice energy which will hydrate to brucite which is a much less soluble more stable alkali.
There are many ramifications and benefits of adding reactive magnesia which depending on the proportion added and the permeability of the substrate all of which have been explained at length on the Tececo web site. We suggest readers start with simple explanations and move on from there to the technical area or numerous papers John Harrison has authored. Quickly the reader will discover there are three main types of cement. Tec-Cements which are equivalent to pre-mix concrete, Enviro-Cements which are especially designed for the immobilisation of toxic and hazardous wastes and Eco-Cements which in a permeable substrate created by the deliberate imperfect packing of particles will carbonate thereby providing an important new way of sequestering carbon.
In relation to strength as all in the industry seem obsessed with this property we so far conclude that for Tec-Cement concretes short term strength is improved and this is an advantage to builders. 28 day strength is usually less, however longer term strength appears to be improved. Durability is significantly improved both chemically and by a marked reduction in shrinkage. The desirable outcome of this is less obvious cracking reducing the litigative cost of this problem. As a bonus rheology is also improved.
Interested? Please read more.
We are in boom times. World physical industrial product (WIP) continues to rise and along with it the consumption of fossil fuels
Approximately four new power plants are being commissioned a week and two of these are in China. In spite of all the rhetoric from politicians about impossible to meet “targets” for emissions reductions, consumption and emissions continue to grow.
According to Di Fazio  "this continued economic growth has brought with it a growing need for raw materials , growing pollution rates, growing use of wood (with consequent growing deforestation rate) and - most important to the growth itself - a fast-increasing need of energy. We know that more than 95% of the energy used by human kind is obtained by burning fossil fuels (oil, gas, coal) and we also know that burning the above mentioned carbon-based fuels inevitably produces carbon dioxide (CO2). For these reasons, the economic growth - i.e. the exponentially increasing WIP - has implied a correspondingly exponentially increasing emission rate of CO2 in the atmosphere and an exponentially increasing CO2 concentration since about 1800. Di Fazio calculates the correlation between World Industrial Product and CO2 emissions as being 99.5% ( i.e. practically 1).
Di Fazio  explains that efficiency is ultimately governed by the laws of thermodynamics and there are limits. Increasing the economic efficiency of burning fossil fuels, i.e. increasing d (WIP)/ d (E) (in $/ton), where WIP is in G$/year and E are the emissions in Gton/year is subject to diminishing returns because the quantity (E) is dependent in turn on the thermodynamic efficiency h = h k/ ac , where k is a thermodynamic efficiency constant and ac is simply the carbon content of the used fuels. It follows from the second second Law of Thermodynamics, h can never reach the value 100%, and - in the real world - it is actually limited to values at most of the order of 60%-80%. Given this and because WIP has been growing exponentially for about 150 years with a doubling time of about every 17 years (i.e. an e-folding time of ~25 years) means that increased efficiency can only reduce emissions by a limited amount. Mathematically the numerator is growing more rapidly than efficiency can change the denominator which can only grow by a limited total factor in the order of 2.5-3.
The modern answer to this dilemma is so called "clean coal" where CO2 from the burning of coal is pumped underground (usually with the co-operation of the oil industry as the gas is used to force up more oil.) My comment is that much work over many years during the cold war and later has established that the risks of pumping the gas underground, due to the fractured nature of the crust, are far too high. This risk the oil industry are keen to ignore and transfer to future generations. Conversion to a hydrogen economy will, at least to the extent hydrogen is produced from petroleum or coal only exacerbate the problem.
More recently we have entered debate around the world for a return to nuclear however as we move to lower grade ores it has been claimed that nuclear generation will produce about a third as much CO2 per kWh as conventional state of the art mid-sized gas-fired electricity generation. In spite of strong rebuttals around the world from the nuclear industry this is axiomatically true to a certain extent.
What this all means is that there is no way we can reduce emissions of fossil fuels even if we markedly increase efficiency. Even if we substantially and rapidly convert to nuclear the rate of change and hence emissions reduction will be too slow because output of CO2 is very connected to WIP and what is more CO2 in the atmosphere has a half life of around 35-40 years. Given the risks of both nuclear and pumping CO2 underground it is essential that we change the physical basis of our economy so that the production of CO2 is balanced by consumption.
In a real world economy governed by market behaviour only profitable changes survive.The present intergovernmental consensus is to foster change by introducing legal costs (carbon taxes) so that market behaviour will tend towards reducing emissions and little emphasis has been placed on promoting technological change that increases sequestration.
It is my considered view that to be ultimately successful a paradigm shift in the technological base of our economy is required that results in profitable uses for CO2 thereby reducing the amount in the atmosphere by economic demand. Professor Cuff and I have developed just such a technology we have called Gaia Engineering. To achieve economies of scale with this technology carbon taxes would be useful but unnecessary in the long run. The resulting changes in materials flows will alter the underlying molecular flow of CO2 to and from the atmosphere in favour of a reduction.
Gaia engineering is economic, produces saleable outcomes and has unlimited markets in size and over time. It is therefore feasible for businesses to adopt and the masses to accept given the short term view of both. Further more it has the potential to sequester sufficient carbon. Gaia Engineering has inputs of waste acid, CO2, brine, seawater or bitterns and outputs of valuable salts, carbonate building materials and cements to bind them as well as in some configurations fresh water - all of which are saleable in very large quantities.
Around 7% of the crust is carbonate sediment and this represents the major proportion of billions of years of natural permanent sequestration and durable structures have been built using this natural carbonate for thousands of years. The technology developed by Gaia Engineering partners mimics this natural process by sequestering carbon dioxide using salty water or bitterns as sources for calcium and magnesium carrier ions and further substitutes the major material flows on the planet by profitably putting the gas to use to make building materials for constructing the built environment.
Peter Hannam in a recent Age article  wrote the following:
"Australia's cement industry would be among the hardest hit by a greenhouse gas emissions trading system, with the sector's annual profit dropping as much as 60 per cent, or $160 million, under worst-case measures, according to Amanda McCluskey, deputy chairwoman of the Investor Group on Climate Change. The basis for such a profit cut includes an emission price of $25 a tonne of carbon dioxide equivalent, and the absence of any free permits, conditions unlikely to be imposed at the start of an emission market, Ms McCluskey told a Committee for Economic Development of Australia (CEDA) lunch .....The profit calculations are based on emissions data from the companies as of last year and use the trading profiles designed by the states.
TecEco are offering the cement industry an opportunity to leapfrog technology thereby neatly overcoming the business risk of carbon taxes or being left behind as governments and consumes rush towards technologies that solve rather than exacerbate the global warming problem. By selling man made carbonate and carbonating binding agents that could potentially be used for the pareto proportion of applications the industry could lead the world. What is more there are very good commercial reasons for the industry to take up this offer.
Sweep environmental reasons for adopting Gaia Engineering and using TecEco carbonate building technologies aside for a moment and consider the technical and commercial advantages for adopting the technology given the current paradigm.
Let me first discuss the shortcomings of Portland cement concretes from the point of view of a geochemist. I don't wish to start a war but Concrete is very much the domain of engineers and this has lead to the propagation of much dogma emanating from ill founded myth! To a geochemist, particularly one not mesmerised by all this and who likes going back to fundamentals such as myself, existing Portland cement concretes are a very imperfect material. The fact is that we spend a lot of money applying top down fixes as a result of the innate defective chemistry of Portland cement and it would be much cheaper and result is wider application and thus probably greater sales if we fixed the chemistry.
The main reason pre-mix Portland cement concretes are chemically defective for purpose is that they contain lime which is far too mobile or reactive. Skeptics who do not believe the truth of this statement should go buy a bag of agricultural lime and put some under their tongues. They may never be able to refute the statement again - literally!
More lime is in concretes today without added pozzolan than a few years ago because the ratio of alite (tri calcium silicate) to belite (di calcium silicate) has increased because the former sets and hardens more quickly and builders keep pushing the cement companies for concrete that does so. Durability, which is a problem for the future and in that sense an externality, does not get the same emphasis and thus modern concretes are compromised in this way. Durability on the other hand is strongly connected to sustainability and will become much more relevant in the future.
So why is lime, called Portlandite by cement chemists, the Achilles heal of modern day concretes? Consider for a moment the thermodynamic properties of Portlandite compared to Brucite in the table below. There is a difference and if you know anything about thermodynamics the numbers in this table should be starting to give you the hint that Portlandite is more reactive than Brucite.
|Thermodynamic Property||Calcium hydroxide (Portlandite, Ca(OH)2)||Magnesium hydroxide (Brucite, Mg(OH)2)||Explanation|
Free Energy of Formation. Delta G (kJ.mol-1)
|-898.408||-833.506||The more negative the Gibbs free energy the more vigorously a reaction will proceed provided there are no kinetic barriers|
Enthalpy of Formation Delta H (kJ.mol-1)
|-986.085||-924.54||The standard enthalpy of formation is used to calculate the heat required or produced in chemical reactions. Visit Wikipedia for a full explanation.|
|Third law Entropy S (kJ.mol-1)||83.39||63.18||A lower entropy indicates greater stability. Visit Wikipedia for a full explanation|
The above thermodynamic factors are important but it is always necessary to also consider the kinetic factors governing reactions. In the case of calcium and magnesium hydroxides, relative solubility is the main kinetic factor as most reactions in concrete occur in solution. The reason magnesium hydroxide is less soluble than calcium hydroxide is quite simply that magnesium is a smaller atom than calcium, and therefore has a higher charge density and bonds much more strongly with hydroxide ions compared to calcium. According to conventional crystallographic electrostatic theory, dipole bond energy decreases proportionally to the square of the bond length and the accepted values are 187.86 kJ.mol-1 for Ca++ and 241.41 kJ.mol-1 for Mg++ respectively. The higher bond energy of magnesium compared to calcium is why magnesium hydroxide is less soluble and therefore less reactive
|Cation radii (6 fold co-ordination, pico metres)||Ion dipole bond energy (kJ.mol-1)|
The small size and consequent higher bond energy of magnesium cations results in lower solubility as the table below shows.
|Name||Formula||Mol. wt.||Density or spec. gravity||Solubility, in grams per 100 cc. (Cold water)||Solubility, in grams per 100 cc. (Hot water)||Solubility, in moles per litre (Cold water)||Solubility, in moles per litre (Hot water)||Solubility product (Ksp)|
|Calcium hydroxide (Portlandite)||Ca(OH)2||74.09||2.24||0.1850||0.0770||0.024969632||0.010392766||5.5 X 10-6|
|Magnesium hydroxide (Brucite)||Mg(OH)2||58.32||2.36||0.0009||0.0040||0.000154321||0.000685871||1.8 X 10-11|
From the above it should follow that lime is far too mobile or reactive to be left in a concrete. It carbonates relatively rapidly and its carbonates shrink just a little mainly through loss of water opening up the surface of concretes allowing other reactive agents such as chloride and sulfate into the deeper matrix. Furthermore lime, called Portlandite by cement chemists, is not a strong mineral and does not develop microstructure that adds to the strength of concrete.
Because pozzolans react with lime forming strong calcium silicate hydrates (referred to in the industry as pozzolanic CSH) to some extent their use alleviates the problem however users should remember that not all pozzolan added consumes lime, some is insufficiently fine or reactive.
In relation to adding pozzolan there is also another looming problem. Most in the industry are blissfully unaware of a problem caused by the addition of pozzolans that affects durability over a longer time frame and that is the de-stabilisation of CSH that pozzolans cause. CSH has an equilibrium pH of around 11.2 and maintains the balance of OH ions in close proximity to it by bleeding or taking up calcium. Removal of surrounding calcium consumed by the pozzolanic reaction that results in a fall in pH of below this figure will result in a drop in the calcium to silicon ratio of the CSH formed from the original Portland cement added and destabilisation through calcium deficit. We do not know how long it will take for this kind of destabilisation to express but have observed embrittlement as a result of the process. TecEco advocate the addition of brucite which plays a secondary role in dense concretes of stabilising CSH by helping maintain the pH balance.
Durability is an externality and not so much on the lips of practitioners in the concrete industry as shrinkage and cracking which are obvious defects dealt with in the real time market place as a cost factor through litigation.
Because shrinkage and cracking are markedly reduced by the addition of reactive magnesia I have written much about the possible mechanisms involved In particular the reader should have a look at newsletter 58. In summary I believe shrinkage, and therefore cracking is curtailed partly as a function of the fact that the water used for the hydration of magnesia whereby brucite is formed comes from mix water which does not therefore exit the mix resulting in volume loss and partly as a result of the extremely kosmotrophic nature of the magnesium ion.
This leads me to what sells pre-mix concrete. The kosmotrophic magnesium ion has a big effect on the rheology of concretes and early strength development. Concretes containing magnesia have a silky feel to them and are easy to finish even with added pozzolans such as fly ash which tends to make the mix sticky.
In Tec-Cement concretes early strength is improved so finishers can go home early partly because of the kosmotrophic affect of the highly charged magnesium ion and also because the surface charge of the magnesium oxide added changes at around pH 12.1 as lime is being produced by the hydration mainly of alite. The result is electro statically induced earlier strength .
At around 28 days strength is usually less depending on the mix and water added however in the long term strength is improved and we think this is mainly because when magnesia first hydrates it traps chemically bound water which is available later for the more complete hydration of Portland cement and completion of the pozzolanic reaction. For techno-buffs this chemically bound water is held between the layers of brucite by polar bonding.
Shrinkage, cracking and rheology are factors in real time concrete markets whereas durability is more an externality and reason enough to seriously study Tec-Cement formulations.. It will however take money to overcome economy of scale issues and develop the TecEco kiln technology which can use non fossil fuel energy. Even without the advantage of using abundant solar power for example, the industry should be aware that the production of reactive magnesia in the context of Gaia Engineering is potentially much less energy intensive than the manufacture of Portland cement and therefore given economies of scale should be much cheaper
All the above and more are compelling reasons for the industry to seriously consider the use of reactive magnesium oxide in cements. We would of course prefer people talk to us before embarking on experiments as it is important to use the right kind of magnesia. We also expect people to sign licence agreements before saying too much!!
 The unit is an index number, set as base=100 in 1963. To obtain with good approximation the value in US$ (1990 value) multiply by 212.1 billion. Doubling time is approximately 17 years. Data: the World Bank; statistics : GDI World Physical Industrial Product.
 Di Fazio, Alberto, The Fallacy of Pure Efficiency Gain Measures to Control Future Climate Change. Astronomical Observatory of Rome and Global Dynamics Institute.
 In Australia Labour has committed to a 60 % reduction from 1990 emission levels by the year 2050. The Liberal government says it will commit to a target, but not until after the next election. Elsewhere around the world the emissions targets called for by various politicians vary from achievable to impossible.
 BP: Statistical Review of World Energy June 2007
 van Leeuwen, J. W. S. and P. Smith. "Nuclear power - the energy balance." Retrieved 25 July 2007, from http://www.stormsmith.nl/.
 Hannam, Peter "Cement to crack with emissions trade','THE AGE',Business day section, page 3, Tuesday, June 19th 2007 said the following
 Amanda McCluskey was formely manager in sustainability for Portfolio Partners in Melbourne and as of 9th July took up a new role as general manager, sustainability at the Commonwealth Bank. The concrete industry should note that even bankers are looking closely as environmental issues!
 Robie, Hemingway & Fisher (1979) Database Last modified July 02, 1996 maintained by the University of California (Berkeley) Web Site at http://www.science.ubc.ca/~geol323/thermo/thermo.htm
 Source for ionic radii: Shannon,R.D. (1976) `Revised effective ionic radii in halides and chalcogenides’, Acta Cryst. A32, 751. This includes further oxidation states and coordination numbers.
 Source for ion dipole bond energies: Lippmann, F. (1973). Sedimentary Carbonate Minerals. Berlin, Heidelberg, New York, Springer-Verlag.
 CRC Handbook of Chemistry and Physics, 74th Edition, 1993-1994
 Glasser, F. P. (1992). Chemistry of Cement Solidified Waste Forms. Chemistry and Microstructure of Solidified Waste Forms Symposium. R. Spence. Oak Ridge, D. Lewis Publishers: 1 - 39.
 The affect of various plasticisers has not yet been determined by rigorous experimentation.
 See Micro Magazine.com for a full description at http://www.micromagazine.com/archive/98/01/small.html
The Association for the Advancement of Sustainable Materials In Construction (AASMIC) is a linking organisation in the supply chain and is seeking the assistance of a retired or retiring professional in the building industry to run its secretariat.
AASMIC was formed by a multi disciplinary group of concerned professionals to promote sustainable materials in construction and an understanding of each others roles in the supply and waste chains.
AASMIC encourages innovative sustainable new materials, disseminates information and stimulates discussion and debate about sustainable materials and sustainable materials in use and related issues. AASMIC also lobbies governments and other agencies about the importance of materials for a sustainable built environment.
The position offered is a part paid / part honorary position with remuneration as agreed between the committee and the successful candidate. It is well suited to a retired or semi retired professional person from the building and construction industry sector who would like to contribute some time & experience back to the industry and society generally. There will also be plenty of opportunity to grow the role and income through activities including conferences.
For more information contact the president or forward an application and current CV to.
Mr. John Harrison,
497 Main Road
Glenorchy, Tasmania 7010
Visit www.aasmic.org for more information and the presidents email address
There are a wide variety of sources of energy for the generation of electricity and it is important to get the mix right of base load and easily adjusted variable load generating capacity.
As far as the environment is concerned, wind power, solar power, wave power, tidal power all seem ideal, particularly for peak load generation, apart from the localized environmental damage caused by their construction. Upon closer examination however many renewable energy technologies are just not yet mature enough to be economical for other than peak load generation and even then they cannot always be relied on. The problem is that practically all sources of renewable energy are dependent on environmental conditions such as wind, water (such as for hydro or the growing of energy crops), tide or sun and the output of energy is consequentially variable and thus unsuited for base load generation. Exceptions include geothermal energy which looks promising and hydro which is still however vulnerable to drought.
As most rivers that can be dammed have been dammed and there are serious misgivings about the environmental affects of dams, nuclear, geothermal and fossil fuel energy are the main options to service our base load energy demands in the future. Power output from gas and hydro can be rapidly changed and are preferable to coal fired power stations as the latter produce waste energy during off peak periods. Excess base load energy should be used to pump water uphill to hydro dams, where the water can be stored and then used to generate electrical energy when there is demand. Natural gas is expensive when compared to coal for electricity generation however has the advantage of being cleaner and more easily adjusted. Oil and natural gas reserves are however fast running out. In comparison there are enough known coal reserves to last hundreds of years at current consumption, making coal a potentially unavoidable long term option for power generation. Given this it is essential that technologies such as geothermal energy, clean nuclear and that can extract CO2 out of the air such as presented in Gaia Engineering are developed.
Geothermal energy is rapidly developing and is an exciting alternative that uses the natural renewable heat coming from the interior of the planet. Some of this heat is fossil heat from billions of years ago and some is thought to relate to natural radioactivity deeper in the planet. The point is it is free and abundant and a rapidly growing source of energy. Nuclear power uses a much smaller mass of fuel when compared to coal and uranium is relatively common in the earth’s crust. Nuclear power plants do not emit greenhouse gasses or other pollutants into the environment to the same extent (See however previous article), they do however produce a relatively small amount of nuclear waste which must be handled safely. Nuclear power has had safety problems associated with it from the past. Newer power stations (some of which use thorium which promises less radioactive by products) have been designed with improved active and passive safety features and better waste handling procedures may provide a satisfactorily clean future for nuclear power generation. A fusion reactor is the ultimate source of cleaner nuclear energy but has not yet been perfected.
By comparison, coal power produces far more pollution than geothermal or nuclear power, however it does not have the same public stigma associated with nuclear energy. Many countries are not building nuclear power plants because of public fear of problems, such as those that occurred at Chernobyl and three mile island. Because the nuclear alternative is unpopular many countries such as Australia have in the past opted for coal.
More recently however there has been a strong renewed interest in nuclear and to a lesser extent geothermal, but given the existing coal based generation infrastructure and looming carbon taxes it is important that the fossil fuel industry clean up its act to the extent possible. A discussion about some of the environmental problems associated with coal fired generation follows.
Coal is relatively cheap and easily available and the most common source of energy for the generation of base load electricity and is thus a major source of carbon dioxide. It is also associated with a large number of other environmental problems, caused both by the mining of coal and the later combustion to produce electricity.
When coal is exposed, water is able to react with iron sulfide and form sulfuric acid. The acidified water leeches into underground waterways where it leaves infertile soil and is able to enter waterways, endangering the life of plants and aquatic animals that are sensitive to changes in pH. Coal mining is also an inherently dangerous activity and whilst it is now relatively safe in western countries, in developing countries thousands of deaths occur annually as a result of coal mining. When a coal seam is depressurized, methane is released from the solid coal. Whilst methane is not directly toxic, it can form explosive mixtures in air and it may displace oxygen in enclosed environments (presenting danger to coal miners etc). More significantly for the global environment, methane is an important and powerful greenhouse gas.
Coal is a relatively impure carbon-based fuel. The combustion of coal releases nitrogen oxides, sulfur dioxide, carbon dioxide and other fine particulate matter into the atmosphere when combusted. Waste products include fly ash, bottom ash, boiler slag, and flue gas desulfurization materials. The waste from coal combustion can also contain mercury and other dangerous heavy metals and well as radioactive minerals..
Nitrogen oxides can react to form HNO3, a component of acid rain caused by coal power stations. Nitrous oxide is also a greenhouse gas and contributes to global warming. Nitrous oxides can react with common organic chemicals and ozone to form toxic products. Nitrate particles and nitrogen dioxide are able to block the transmission of light and are a significant component of smog.
The oxidation of sulfur dioxide in the presence of a catalyst such as NO2 results in the formation of sulfuric acid which is the major acid-rain causing pollutant emitted from coal power stations:
2SO2 + O2 => 2SO3- SO3 + H2O => H2SO4.
The amount of sulfur dioxide present in the exhaust depends upon where the coal was mined. Acid rain can corrode buildings and can have adverse effects upon flora and fauna. There is some research to suggest that acid rain can have possible direct impacts on human health and long term exposure has been linked to asthma symptoms. Soil without a high alkaline content is especially vulnerable to acid rain, it becomes infertile until treatment with alkalis, a financial burden on the agricultural industry.
Fly Ash is the solid, fine, particulate residue resulting from the combustion of coal. It consists primarily of silicon dioxide, aluminium oxide and iron oxide. Fly ash is not generally considered environmentally hazardous (unless radioactive - see below), but it is responsible for most of the direct health effects surrounding coal combustion. Inhalation can cause bronchitis, silicosis (lung scaring) and is associated with increased risk of scleroderma and lung cancer. If collected, Fly ash can be used along with boiler slag and bottom ash as a cement additive or filler material for low strength applications.
The combustion of coal also produces low levels of naturally occurring radioactive isotopes. This can lead to environmental radioactive contamination near high output power stations. The concentrations of radioactive material in coal ore are relatively low, however the volume of coal burnt means that significant amounts of these substances are released. The amount radioactive material released from a coal power station is approximately 100 times greater than that of a comparable nuclear plant.
There are a number of approaches that can help make coal mining "cleaner" and more environmentally acceptable. Methane can be captured from coal seams and used to provide power from gas and limestone or other treatments can be used to treat acid mine drainage. Appropriate occupational health and safety regulation and enforcement can improve miner safety where it is neglected. Improvements in the efficiency of any non-renewable power source will directly lower its impact on the environment. This can be achieved by lowering the emissions caused by the movement of coal from mines to power plants, by building the power plants closer to the mine locations. Efficiency can also be improved by lowering the transmission losses, by the usage of higher voltages to transmit electrical energy from one place to the next, and by decentralizing power plants, using many smaller plants rather fewer large ones. Waste heat from industry can also be used to generate electricity. Note however that there are practical thermodynamic limits to efficiency in the first article in this newsletter.
Bill Courtney from Cheshire Innovation has pointed out that at least half of the energy used to heat steam is wasted when only one thermodynamic cycle is used to extract useful work for electricity generation. The best single cycle turbines in use for current power plants are able to achieve efficiencies of around 45% and older power plants are far less efficient. Improvements can be made to the thermodynamic efficiency by utilizing more than one thermodynamic cycle to extract work. A combined cycle coal power station could use the Rankin Engine to extract energy from the transition from liquid to water vapour and the Newcomen Engine to use the pressure change and heat released from the transition back to liquid again. If and when developed, this technology could easily be fitted to existing power stations almost doubling their efficiency bringing it much closer to the practical second law of thermodynamics limit of 60-80%..
Some pollutants created by the combustion of coal can be collected and prevented from entering the environment however as of yet there is no economically viable way of concentrating carbon dioxide in flue gases other that possibly the Tec- Reactor Hydroxide/Carbonate Slurry Process described by Gaia Engineering at http://www.gaiaengineering.com/gaiaengineering.hydroxide_carbonate_slurry_process.php.
Fly ash can be filtered from the exhaust gas of coal power stations using electrostatic precipitation, which is able to remove 99% of all fly ash from the flue gas exhaust. Precipitators work by inducing an electrostatic charge on particles, attracting them to charged plates where they are easily collected. A negative side effect of electrostatic precipitation is the production of ozone and nitrous oxides. Particulates can also be collected from flue gas using filter bags and wet scrubbers. These methods are generally not cost effective and are therefore less common.
The amount of sulfur dioxide present in flue gas depends on where the coal was mined. When the coal used is high in sulfur, flue gas desulfurization systems can be used to remove sulfur dioxides. Wet scrubbers are the most common and involve a water solution containing lime sprayed over the gas as it escapes the tower. The sulfur dioxide is absorbed into the spray, and reacts to form wet calcium sulfite, which can be converted to gypsum, useful for products such as plaster and fertilizer.
The output of nitrous oxides can be reduced through the use of low NOx burners. These burners work by restricting the amount of oxygen made available in the hottest part of the coal chamber. This limits the formation of the gas, lowering the amount of post combustion treatment required. The remaining nitrous oxides can be captured using similar scrubber systems as with sulfur dioxide.
Coal power stations are responsible for the emission of significant amounts of carbon dioxide and coal gasification technology will still produces carbon dioxide gas. There has been research into carbon capture systems, where the exhaust carbon dioxide is captured, prevented from entering the atmosphere and pumped deep underground or otherwise sequestered to prevent its release into the environment. Of these mineral sequestration is too expensive and geosequestration (whereby liquid CO2 is pumped deep underground) expensive and in our view far to risky. Our favoured option is the Tec-Reactor Hydroxide / Carbonate Slurry Process described on the Gaia Engineering website as it is the only safe and potentially profitable option.
None of these solutions have been significantly implemented into commercial processes as they are not required by government legislation. Carbon taxes will hopefully raise the incentive for further investment.
Another approach to lowering the amount of pollution caused by coal power plants involves removing the pollutants before the coal is combusted by turning the coal into its gas components, principally carbon monoxide and hydrogen, other gasses that are given off during the process can be used for chemical and fertilizer manufacture. Coal gasification is advantageous because any dangerous or non combustible materials can be removed. Current gasification technology produces a “syngas” containing hydrogen and carbon monoxide. Unfortunately carbon dioxide is still produced will have to be captured in a "clean coal" scenario. Because the coal is split into its components by being heated in the absence of oxygen, there is an inherent energy cost in converting coal to gas, lowering the efficiency of combustion.
The words clean coal are a misnomer as coal can never be clean. It can however be much cleaner than it is. The environmental impacts of coal power stations can be significantly reduced at the mining stage, by treatment prior to combustion, capture of pollutants after emissions, with coal gasification technology, by improving the efficiency of coal power plants and in the context of Gaia Engineering.
Excess atmospheric CO2 created by the burning of fossil fuels is believed to be a major cause of global warming. To counter this, industries directed towards the uptake and sequestration of atmospheric CO2 are being promoted through a system of Carbon Credits that can be traded with CO2 producing industries. Major carbon exchanges currently exist in Brussels, Chicago and more recently NSW and potential opportunities still exist in Australia dependent upon legislative changes by State and Federal Governments.
A common form of carbon sequestration currently supported financially by Carbon Credits is the planting of biomass such as in tree plantations. Alternatively ocean nourishment is proposed as a process for stimulating the sequestration of atmospheric carbon dioxide in the deep ocean by providing the nutrients needed to enhance the biogenic production of phytoplankton with carbonate skeletons. Both have problems. The sequestration of CO2 through the planting of biomass (e.g. tree plantations) is relatively short term in geologic and climatic time frames as the sequestered carbon is released as the biomass decays. Fertilising the oceans to the south of Australia with iron could have countless unforeseen consequences and should not be done prematurely without much more research.
A solution is required that is safe, has other environmental benefits and is profitable because it converts CO2 into a resource. Such a solution has been created by the Global Sustainability Alliance and members are concerned with the over emphasis on a particular form of geosequestration, that of pumping liquefied CO2 into underground storage reservoirs.
The term geosequestration is a jargon word derived from the Latin root “geo” meaning earth (geography, geology etc.) and sequester (ation) from the Latin for a depositary. The term was originally used generically for technologies for geologically sequestering CO2 and included what is today referred to by many as mineral sequestration. The fossil fuel industry have attempted to take over the word to add credibility to pumping gaseous or liquid CO2 into underground “storage” usually with the pecuniary advantage of also forcing up more oil.
There are two main problems the second of which cannot be overcome as it is a risk inherent in the process.
1. Apart from the Tec-Reactor Hydroxide / Carbonate Slurry Process mentioned in the previous article about energy, there is no economically viable method of concentrating the CO2 in the flues of coal fired power stations.
Gaia Engineering partners are seeking funds to research this method and have several ideas to improve it.
2. There is an unacceptable level of long term risk in pumping CO2 underground.
During the cold war extensive work was carried out to determine the practicality of storing gas underground and the general conclusion was that doing so was not feasible. Pumping liquid CO2 deep underground is a short term, risky and temporary solution to the now urgent global carbon dioxide concentration problem. We contend that it should only have a limited role to play in what should be a more holistic approach to the issue. The reality is that compressing carbon dioxide and pumping it long distances and eventually underground is a risky, high cost waste of an as yet unrecognised resource. The technology would not have gained any credence at all if it was not promoted by the oil industry because it is also a useful technology for forcing oil out of the ground under pressure from dwindling reserves.
As distinct from pumping liquid CO2 underground, permanent carbon dioxide (CO2) fixation (‘sequestration’) involves the immobilisation of CO2 from the atmosphere by precipitation as solid carbonate mineral phases, typically calcium carbonate (CaCO3) and magnesium carbonate (MgCO3) geomimicing nature as the main sink for the gas as 7% of the crust is carbonate sediment and represents by far the greater proportion of natural sequestration in the last few billion years. We therefore question the manner in which the coal industry and the Australian government has focused only on depositing liquid CO2 underground and examined none of the safer, more logical and more economic alternatives available.
What we should be doing is mimicking nature and finding uses for CO2 as my company TecEco have done. The permanent fixation of carbon dioxide accomplished by the Gaia Engineering process is an entirely different form of permanent sequestration with as yet no known downsides.
Australia has 24 large power stations supplying 80% of our electricity burning coal and producing a quarter of a million tonnes of CO2 every day (Horstman 2006 ).
Pumping CO2 underground has been proposed so we can keep using oil and coal. It involves capturing the gas at power stations, compressing it into liquid CO2, piping it to a suitable location (usually an oil well) and then injecting it deep underground where it is hoped it will remain trapped for thousands of years.
The concept of putting CO2 as a gas back into the ground from whence it came concern us because, as a rule nature has not buried carbon dioxide as a gas in sediments, although it occasionally emerges in a concentrated form in volcanic areas causing loss of life. If we are to learn from nature’s 4 or 5 billion year old experiment, then geomimicry principles require the burial of CO2 by first making it a non reactive solid as has occurred naturally during the formation of carbonate sediment during previous periods of global warming including the Carboniferous and late Permian whereby some 7% of the crust is carbonate sediment.
The earth is highly fractured and holding compressed liquid CO2 at depth and preventing escape, adverse reactions and other catastrophes occurring is problematical. During the effluxion of time, unless the gas is converted to a chemically stable solid, it will naturally migrate to regions of lower pressure such as at the surface, or as has been demonstrated, combine with salt and react with country rock thereby migrating in this manner (Kharaka 2006 ).
Gaia Engineering is a alternatives which geomimics natural processes by creating mand made carbonate sediment preferably from brines or seawater and using it to construct the built environment with Eco-Cements. Gaia Engineering is therefore a more exciting and a much more economic and appropriate use of taxpayer funds.
Mineral sequestration is a term generally used in reference to using serpentines, olivines or peridotites to sequester CO2. The technology was first mentioned by Seifritz (Seifritz 1990 ) and discussed further by Dumsmore (Dunsmore 1992 ). However, Lackner and his associates (Lackner, Wendt et al. 1995  ) were the first to provide the details and foundation for current research into the technology.
Permanent sequestration as a solid stable carbonate mineral is axiomatically much safer than pumping CO2 as a liquid into underground reservoirs and to this extent support mineral geosequestration as suggested by the above authors and others.
The main problem with the abovementioned technologies however the high cost whiich are furthermore not offset by the production of useful by-product.
To be successful in the long run any sequestration process must be profitable and involve the conversion of CO2 into a resource. To do this TecEco have developed an economically viable industrial tececology referred to as Gaia Engineering that mimics nature. This biomimicry-geomimicry process includes a number of components that together will make sequestration profitable.
Refering to the above diagram, possible front end processes including inputs and outputs are shown in the following table:
|Greensols||Seawater or brines, waste acid and CO2||Mineral salts, carbonate building materials and aggregates, Eco-Cements and fresh water||Greensols Pty. Ltd.|
|Calera Process||Salt water||CO2||Scientific American|
|Hydropyrolysis of Bitterns||Bitterns and water||Mangesium oxide and chlorine gas (or hydrochloric acid). This process could be combined with the greensols process to supply acid.|
|Ultra Centrifuges||Seawater or brine||Provided materials can be found to withstand the forces involved, potentially similar by products to the Greensols process.|
|Carbonic anhydrase, saltwater or brines and CO2||
Using carbonic anhydrase and other enzymes to mimic carbonate formation in nature. Catalysts like carbonic anhydrase could also feasibly be used with our cements to speed up the carbonation process.
Once captured the carbonate flows through an evolving number of key sub-processes depicted in the figure above. They include:
and end up as carbonate building materials for the built environment.
The concept of using CO2 and other wastes as resources to build the built environment is without equal, and can only be achieved profitably. The key is to produce valuable materials and in the case of Gaia engineering this also extends to profitable by - products.
If adopted on a large scale Gaia Engineering would sequester significant amounts of atmospheric CO2 and convert significant wastes to resources. All of the outputs from the process uniquely provide revenue to help make the overall process economic.
The crust of the earth is always prone to tremors and earthquakes and there is a high probability that pumping liquid CO2 underground will not always work as expected. Should the technology fail the consequences will be significant. Consider the Costs and Risks.
The International Panel on Climate Change estimate burial costs of between 15-75 dollars per tonne of CO2, depending on the method (Metz et al 2005  ). The actual figure is still a guess. The point is that pumping liquid CO2 underground will be very expensive. Much more expensive than the Gaia Engineering proposal as no useful product is involved other than in the remote possibility in Australia that it may be used to extract previously economically unviable oil deposits, further compounding the problem.
Estimates abound of up to a third as much energy would be required to capture compress, pump and store the CO2. Regardless of the exact extent of this unknown energy cost, it will be high.
The earth is highly fractured and compressed gases have a habit of wanting to migrate to zones of lower pressure and once again become gases. During the cold war extensive research concluded that storing gas underground was too risky – has something changed?
CO2 has escaped before as in the 1986 Cameroon disaster that killed some 1700 people and the consequences would be disastrous if it happened on a large scale as a result of underground storage of massive amounts of the gas.
There are many geological reports outlining the risks such as recently reported by New Scientist (Kharaka 2006 ) and it is not my intention to reiterate them further.
The main problem so far recognised with mineral sequestration is that of cost. The Global Sustainability Alliance think that this will only get worse with the rising price of fuels as the process involves mining and transport.
Cost estimates for the industrial-scale implementation of current mineral carbon sequestration processes range from $60-100/ton CO2 avoided for the direct carbonation of olivine to several hundred dollars per ton of CO2 avoided for the direct carbonation of serpentine. (Krevor and Lackner 2005 ) This is way to high to be feasible.
Calcium or magnesium carbonate solids are the thermodynamic ground state of carbon and to this extent there is very little risk of catastrophic failure. The problem is more a risk that in spite of continued research viable chemical processes for reacting magnesium silicates with CO2 sufficiently rapidly and cheaply will not be found.
To John Harrison and other The CarbonSafe Alliance members, adding value to carbon dioxide by developing uses for it is by far the most sensible option. Pilzers “first law” stated simply is that the technology paradigm defines what is or is not a resource (Pilzer 1990 ) ). Uses are found by changing technology paradigms and to this end Professor Chris Cuff and John Harrison have formed the the Global Sustainability Alliance to mimic nature and use carbon and other wastes to create the built environment. Eco-cements are a perfect example of geomimicry whereby material that is indefinitely stable is created out of carbon dioxide in the air.
The long run costs of making carbonates and Eco-Cements for use in constructing the built environment using the Gaia Engineering process should be very low, especially since other valuable product is also produced. The process temperatures are low, the energy efficiency high and the source of magnesium is abundant, universally available in sea or groundwater and cheap. Given current emissions, only around 22 billion tonnes of man made magnesium carbonate (magnesite) are required to be deposited a year to reverse global warming. This is in the same order of mass as the concrete we already make. The key is to use some of that magnesite to replace concrete. Our calculations show that magnesium in sea water would last over a billion years with natural replenishment. With replenishment – probably indefinitely. Cost are not yet defined but expected to be much lower than any other technology.
As stated earlier, magnesium carbonate is very stable. As the Eco-Cement technology has already been proven there is no risk. The Greensols process has been laboratory tested and will work.
 Horstman, M. (2006). Geosequestration. ABC Catalyst.
 Kharaka, Y. (2006). "Carbon Dioxide's Great Underground Escape in Doubt." (2560).
 Seifritz, W. (1990). "CO2 disposal by means of silicates." Nature 345(486).
 Dunsmore, H. E. (1992). "A Geological Perspective on Global Warming and The Possibility of Carbon Dioxide Removal as Calcium Carbonate Mineral." Energy Convers. Mgmnt, 33: 565-572.
 Lackner, K., C. Wendt, et al. (1995). "Carbon Dioxide Disposal in Carbonate Minerals." Energy 20: 1153 - 1170.
 Metz, B. D., Davidson, Ogunlade, Coninck, Heleen and M. M. Loos, Leo (2005). Carbon Dioxide Capture and Storage, Intergovernmental Panel on Climate Change.
 Krevor, S. C. and K. S. Lackner (2005). "Mineral Carbon Dioxide Sequestration: Still Viable Option."
 Pilzer, P. Z. (1990). Unlimited Wealth - The Theory and Practice of Economic Alchemy, Crown Publishers.
In 2006 global CO2 emissions from fossil fuel use increased by about 2.6%, which is less than the 3.3% increase in 2005. These figures are based on a preliminary estimate by the Netherlands Environmental Assessment Agency (MNP) using BP energy data (BP, 2007). The increase in 2006 is mainly due to a 4.5% increase in coal consumption:
* global CO2 emissions from coal combustion increased 4.5% (+500 megatonne CO2). China contributed most to this increase with a 9% increase in 2006 (vs. 12% in 2005). In the rest of the world coal combustion emissions increased by 2%.
* global CO2 emissions from combustion of natural gas increased 2.5% (+130 megatonne CO2), mainly due to increasing consumption in Russia and China.
* global CO2 emissions from combustion of oil products increased only 0.7% (+90 megatonne CO2), mainly due to a decrease in consumption in OECD countries by 0.9% on average.
Total fossil CO2 emissions of China increased in 2006 by 8.7%. In the USA, according to the BP data CO2 emissions decreased in 2006 by 1.4% relative to 2005. Fossil CO2 emissions of the European Union countries “EU-15” remained almost constant in 2006; in 2005 these decreased by 0.8% according to a recent report by the EEA compiling data from the member states (EEA, 2007).
In 2005, the CO2 emissions of China were still 2% below those of the USA. Since 2006 however, China’s CO2 emissions from fossil fuel use and industrial processes (cement production) have been greater than US emissions. With approximately 8% higher emissions than those of the USA, China now tops the list of CO2 emitting countries. The EU-15, with a volume of emissions about half of that of China, occupies the third position, followed by Russia, India and Japan.
Cement clinker production is the largest CO2 source among industrial processes, contributing about 4% of global total CO2 emissions from fuel use and industrial activities. However, for China with its large and increasing share in global cement production of about 44% in 2006, the share of CO2 from cement production in national total CO2 emissions is almost 9% (550 megatonne out of a total of about 6200 megatonne CO2). For the USA these figures are about 5800 megatonne CO2 in total, of which 50 megaton is from cement production.
* Global greenhouse gas emissions increased 75% since 1970
* BP, 2007: Statistical review of World Energy 2007
* EEA, 2007: EU greenhouse gas emissions decrease in 2005
* IEA, 2006: CO2 Emissions from Fuel Combustion 1971-2004
* ITC, 2007: CO2 emissions from underground coal fires in China
I recently celebrated by 58th and a friend gave me the following equation for my birthday.
I though this rather good and so I am sharing it with you!!