Sequestration in the Built Environment

The overriding objective for sustainability is to get CO2 out of the air. To do this we have to change the technical paradigms which are the basis of our techno-process.

James Watt invented the steam engine and this used coal. Somebody else came along and said oil is better because you can carry it about in a barrel. A few thousand inventions later and you have the well developed techno-process that now dominates our lives, our landscape and unfortunately our planet. We have experienced a technical revolution of huge proportions.

Underlying the flow of all the materials that are involved are moleconomic flows in the global commons that are damaging to everything that lives in our biosphere and upsetting flows in the geosphere. To mention but a few; heavy metals, CFC's and of course CO2 in the air. We are choking and poisoning ourselves - slowly. It's a bit like the old agar dish experiment from biology at school - remember how it works? You put a spec of bacteria in the middle of a food supply loaded in agar jelly and behold - the bacteria grows in a ring to the edge of the dish dying in the middle as the poisons in its world (the dish) kill it. There is no escape.

How can we avoid this fate? Fortunately the world is a big place and there are externals not present in the agar dish. Winds, tides and currents circulate nutrients like oxygen, microscopic food in the sea and take a way wastes. We used to live in a balanced ecological system where supply and demand were as in a stable economy balanced. We are alive because in natural systems that are in equilibrium there is little waste, or poison. Everything that is produced naturally is used naturally. That is until we came along with our machines and threw the whole lot of balance.

According to the Worldwatch Institute "In 2002, the world's passenger car fleet hit 531 million. A quarter of these cars were in the United States, a country with just five percent of the world's population, and a long known love affair for the automobile. The average car in the US travels 10 percent more each year than a car in the United Kingdom, about 50 percent more than one in Germany, and almost 200 percent more than a car in Japan." All these cars along with the airplanes, power stations and so on use fossil fuels and are upsetting our global carbon balance. Let's face it we have used up over half of the last few billion years worth of carbon stored by nature in the form of petroleum, and a somewhat lower proportion of the total coal.

Even if we were to convert all our cars to non fossil fuel, master fusion reactions and shut down our coal fired power stations it would take hundreds of years for global warming to reverse because CO2 in the atmosphere has a half life of around 50 years[1] and there is a marked lag between emissions and warming.

How can we turn this juggernaut of such immense proportions around?

The current strategy adopted by most countries is not holistic, is insufficiently broad based and will not work. Given human nature massive emissions reduction in the order of 50-80% being discussed is not going to be achievable without carbon rationing and that may lead to more conflict that is predicted to occur as a result of global warming. So called clean coal is an oxymoron. Coal is the dirtiest burning of all fuels and burying carbon dioxide in our leaky old earth costly and fraught with danger for future generations. Weaning ourselves from fossil fuels and learning how to use the flux of energy coming from other sources is important but even though these energies are of immense proportions and everywhere [3] they are hard to capture.

A more holistic approach would disclose the obvious. We must find ways of getting the CO2 out of the air as well as reduce the rate at which we are putting it there. These ways will not be effective unless everybody everywhere is using them so they have to be economic. They have to produce real tangible benefits that satisfy human survival instincts because human beings can never be expected to do anything just because it is the right thing to do. That is the responsibility of governments. Unfortunately however governments are only elected for a few years and the people involved are driven not so much by statesmanship but by the need to keep their jobs! The problem of externalities such as emissions discussed by Aristotle and Plato continues.

We have no choice but to change the technical paradigms which are the basis of our techno-process. We must do things differently. Pilzer's first law predicts that changing the technical paradigms will change resource flows[2] and thus underlying moleconomic flows in our techno-process. We could if we wanted to hard enough actually reverse the flow of CO2 into the atmosphere. It is a matter of changing the flows in our techno-process and redefining CO2 as a resource.

A technical revolution the size of the one started by James Watt is required. The Global Sustainability Alliance offer Gaia Engineering which, focusing on the major materials flows in the built environment[4] because of their size. Gaia Engineering, is a tececology that is big enough to reverse global warming. In nature CO2 is used to create the homes of the vast proportion of plants and animals. Realistically to save our civilisation we have to do the same and find ways of incorporating carbon into our built environment. Gaia Engineering geomimics nature, providing a cheap way of using the built environment as a repository for carbon dioxide and waste.

Using Gaia Engineering and TecEco Eco-Cement and Tec-Kiln technologies we can change global carbon flows as in the diagram below.

The Carbon Cycle Modified by Gaia Engineering

By using carbon dioxide to build our homes just like shellfish and trees do the Gaia Engineering tececology works like a giant ecological pump to reverse the problems of global warming and waste.

Magnesium oxide-hydroxide-carbonate systems are favoured by Gaia Engineering because magnesium has a low molecular weight, bonding with significant amount of CO2 [5] ; its oxide is easy to make using our Tec-Kiln technology without releases and the element is abundant in the ocean and brines. Water containing magnesium is a resource of every country on earth. Driving the magnesium thermodynamic cycle to carbonates or even a complete cycle to sequester CO2 does not take huge amounts of energy and can generally occur at low temperatures using non fossil fuel sources.

The Magnesium Thermodynamic Cycle

In Gaia Engineering the magnesium comes from sea water or brines and is precipitated as carbonate in the Greensols Process. The process will be economic because other valuable minerals are produced as by products. Some of these precipitated carbonates will be used directly as building components in the built environment. A binder will be required to hold these components together and TecEco's solution is magnesium Eco-Cement made without releases to the atmosphere from the carbonate produced by Gaia Engineering.

The important step for sequestration by Eco-Cement is the carbonation of magnesium from solution or precipitated magnesium hydroxide whereby nesquehonite or other magnesium carbonates (many of which are also hydrated further adding to the volume of material produced) are formed. TecEco have demonstrated that carbonate binders work, are achievable relatively easily and sufficiently rapidly. We have been using mined carbonates such as magnesite, dolomite and limestone for years to build with. The switch to man made carbonate is a logical solution. With capture of CO2 during manufacture as proposed by TecEco using our Tec-Kiln and substitution of major flows in the built environment such as that of concrete with carbonate, sequestration on a massive scale is possible.

As stated by Fred Pearce in the article on Eco-Cements published in the New Scientist magazine (Pearce 2002[6] ) “There is a way to make our city streets as green as the Amazon Forest. Almost every aspect of the built environment from bridges to factories to tower blocks, and from roads to sea walls, could be turned into structures that soak up carbon dioxide – the main greenhouse gas behind global warming. All we need to do it is the change the way we make cement.”

Sequestration With and Without Capture of CO2 during the manufacture of Eco-Cements

For a well balanced strategy to save our civilisation from global warming, as in nature, we believe it essential to also instigate a plan to reverse the flow of CO2 in our techno-process using the Gaia Engineering tececology. Humans, rats, fleas and cockroaches will not notice the difference with a shift to using carbonate, it could even be cheaper. Most importantly doing so will save our climate. There is no need to fear the change as economic history demonstrates clearly that change, properly managed stimulates economies.

With the capture of CO2 during the manufacture of Eco-Cement and using carbonate building components from Gaia Engineering the sequestration potential is enormous and pales into insignificance other sequestration solutions. TecEco have developed an LCA model for its Eco-Cement which is downloadable from the web site that is a useful tool to demonstrate exactly how much CO2 could be sequestered by its cements. Using building components that are solid carbonate will sequester much more.

Using our LCA model it is possible to model the emissions or sequestration with or without capture of CO2 and switch other variables. With carbon capture during manufacture net sequestration is possible as in the following diagram

Sequestration Using Eco-Cement Calculated with Carbon Capture

Many scientists think that we have a ten year window to turn global warming around. Even if they are all wrong it makes sense to move towards sustainability because living more sustainably in the long run involves spending less on resources like fuel and materials. Our wastes become our resources and our energy could come freely from the sun.

It is essential therefore that the funds required to develop the TecEco Cement and Tec-Kiln technology is forthcoming soon and at TecEco we think this is very much the role of governments.

Maybe then we could experience the security of moving into a low carbon future.

A Low Carbon Future?

 

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